  Ermine (Synonymy under subspecies)
Characters for ready recognition.—Differs from Mustela rixosa in presence of black pencil on tail, tail-vertebrae more than a fourth of length of head and body, and in regions where the two species occur together, basilar length of skull more than 32.5 in males and more than 31.0 in females; from Mustela frenata, in regions where the two species occur together, by tail less than 44 per cent of length of head and body and by postglenoidal length of skull more than 46 per cent of condylobasal length in males and more than 48 per cent in females. Characters of the species.—Size medium to small (total length 225 to 340 mm. in males and 190 to 290 mm. in females); tail 30 to 45 per cent of length of head and body, with distinct black pencil; caudal vertebrae 16 to 19; skull with long braincase and short precranial portion; postglenoidal length, when expressed as a percentage of the condylobasal length, more than 48 in females and ordinarily more than 46 in males; upper parts brown; underparts whitish, ordinarily continuous from chin to inguinal region but in subspecies in the humid region along the Pacific Coast interrupted in some individuals by brown of upper parts encircling body in the abdominal region. The soles of the feet in each of the subspecies are densely haired in winter and have only a relatively small area of the foot-pads exposed in summer, the intervening areas being well haired even at that season. The uniformity throughout the species as regards hairiness of the foot-soles and also the character of the vibrissae makes it unnecessary to describe these features in the accounts of the subspecies of erminea. Geographic variation.—In the Old World 16 or more subspecies are currently recognized and there are 20 in North America. The features in which geographic variation is especially prominent are: First, size, as expressed by external measurements and weight, second, color pattern, depending on the extent, in relation to one another, of the dark-colored upper parts and light-colored underparts, and third, breadth and depth of the rostral region of the skull. Except in size, the variation in the skull is less than in M. frenata. Likewise in tone and shade of upper parts and hue or tint of underparts, erminea is less variable than frenata and has the face all of one color without the contrasting color-pattern of the face and head seen in many subspecies of frenata. M. erminea exceeds frenata as regards variation of the size of the area occupied by the light-colored underparts. At one extreme is the subspecies arctica in which the area of the light color extends well up on the sides of the body, down the insides of the legs, over the feet and far out on the lower side of the tail whereas at the other extreme are the races streatori and olympica in which the light-colored underparts are restricted to two areas, one on the chin, throat and chest, and the other on the inguinal region. These areas may or may not be connected by a thin line of white color along the midline of the underparts. In size of animal, erminea probably exhibits the maximum variation among American species of weasels; an average-sized male of the race arctica weighs 4 times as much as one of the race muricus, and in the species frenata I doubt that the difference is quite as great between individuals of the smallest race, effera, on the one hand, and either of the largest races, texensis or macrophonius, on the other hand although actual weights are not available for these races of frenata. As elsewhere indicated, the small-sized individuals of M. erminea are of the southern races and the large-sized individuals are of the northern races. This decrease in size southward occurs both in Asia and in America. Natural History.—Habitat and numbers.—Along the International Boundary east of the Turtle Mountains, Soper (1946:136) found this species present only in timbered areas and absent from many untimbered areas. Of the same species to the westward he comments "so far as I know at present, there is no evidence to show that any short-tailed weasels inhabit a broad strip of treeless territory immediately north of the International Boundary in Canada from southwestern Alberta to southeastern Saskatchewan." The same author (1942) reports that in the general area of Wood Buffalo Park, Northwest Territory, south of Great Slave Lake, the ermine is uncommon on pine-grown sand ridge and rolling upland and common in lower spruce-aspen parklands, stream-side coniferous belts, and grassy, semi-wooded swamplands. Nine ermines per square mile is the number that Soper (1919:46-47) estimated at Edmonton on the basis of the numbers that he trapped there in the winters of 1912-13 and 1913-14 and on the basis of the tracks of remaining ermines. From corresponding data he estimated the population in the winter of 1913 on the Hay River, north of Jasper Park, to be nine per square mile. In each of these instances he estimated ten weasels per square mile but he inclined to the view that one-tenth of the animals involved in his counts were long-tailed weasels (Mustela frenata). Osgood (1909B:30) and his field companion in the period July 31 to September 3, 1903, took a series of 42 specimens within a radius of 500 yards of their camp at the head of Seward Creek, Alaska, all caught in four traps, in one month. Of the 42 specimens, 28 are males and 14 are females. Fluctuations of a multiannual nature are marked in this species. Bailey (1929:156) observes that in Sherburne County, Minnesota, when meadow mice are abundant for two or three years these weasels become abundant but that when the mice are scarce the weasels also become scarce. Manning (1943:56), on Southampton Island, noted "that the maximum and minimum points of the weasel cycle are much more sharply marked than those of the fox cycle and the increase and decrease are more rapid." How far an ermine will travel in a given length of time has seldom been recorded but Hamilton (1933:293), on March 20, 1932, "followed the track of a small weasel, presumably a male cicognanii, for four miles in the fresh snow," and Ingles (1942) observed a diminutive ermine of the subspecies M. e. muricus, at Woods Lake, California, 286 yards from its den. BehaviorAs regards locomotion, Soper (1919:46), in reference to Mustela cicognanii, presumably in Ontario, Canada, writes that in the bounding gait the hind feet register almost, if not exactly, in the front-foot impressions, with the right front and hind feet lagging slightly behind. "The distance normally is about 19 inches, representing a regular rate of travel.... In traversing open spaces they resort to long, graceful leaps upwards of six feet in length.... I measured a record ... of 8 feet, 2 inches." Of M. e. arctica, Dice (1921:22) writes that when it runs "the tail is carried off the ground usually at an angle of about 45 degrees." Seton (1929 (2):598) states that "At Carberry [Manitoba] I have often seen this energetic little creature seeking for Mice in the deep, soft snow. Its actions are much like those of an Otter pursuing salmon. Sometimes it gallops along a log, or over an icy part of the drift; then plunges out of sight in a soft place, to reappear many yards away...." Little is recorded concerning swimming but on this score Seton (1929 (2):602) does quote J. W. Curran, who in July, 1899, at Lake Couchiching, Ontario, watched an ermine pursue a chipmunk into the water and for 100 yards before giving up the chase and wheeling around and making for shore. In swimming "The Weasel, I think, showed more of his body, and seemed to exert himself more" than the chipmunk. As to voice, Dice (1921:22), at Tanana, Alaska, heard the ermine, when excited, bark somewhat like a mink but not so loud and Seton (1929 (2):606) quotes Manley Hardy to the effect that the species has a purring note. Sense of smell was used by an M. e. muricus that Dixon (1931:72) watched as the ermine followed a three-fourths-grown pika. Concerning the ermine at Carberry, Manitoba, Seton (1929 (2):598-599) writes that "The smell of blood must be as far-reaching as it is attractive to these sanguinary little creatures. I have frequently hung new-killed Rabbits and partridges temporarily in trees, and, after an absence, in some cases of a few minutes only, have found an Ermine mauling the game, though there was no sign of such a visitor when the cache was made." EnemiesGeorge Measham, of Winnipeg, found sign in the snow indicating that a great snowy owl had killed an ermine and T. McIlwraith shot a bald eagle at Hamilton Bay which had the bleached skull of a weasel (probably of this species) clinging to the throat (Seton, 1929 (2):603). A. B. Howell (1943:98) likens mustelid mammals to domestic cats in their manner of crossing roads and thinks that mustelids loiter at the side of the road until the stimulus of the approaching car causes them to make a dash whereupon they are caught by the wheels and killed. Three of four weasels seen to cross the road were killed, one even having apparently crossed the road before turning back and being killed under the car. One weasel killed was Mustela erminea cicognanii. Dalquest (1948:190) in writing of this species in the state of Washington, says "I have seen only one abroad in the daytime. It dashed from a roadside thicket ... and was crushed beneath the wheels of a car." FoodThe killing of prey is described by Hamilton (1933:332) as follows: "A rapid dash, and the bird or mouse is grabbed over the back of the skull, the fore legs encircle the animal as though hugging it, and the hind legs are brought up to scratch wildly at the captive.... If [the prey is] a large animal, as a rat, the weasel usually lies on its side, while the diminishing struggles of the rodent continue, but if a mouse or a small bird [is the object of attack], the weasel is apt to crouch over its prey. Little time is lost over the first [mouse] ... if two mice are present [;] a strong bite through the brain case ... [is] sufficient. If only one animal is present, the weasel dawdles over its kill some time after life has departed." Hamilton's (1933:333) study of the contents of the digestive tracts of bodies of ermines obtained from fur trappers and fur buyers in New York enabled him to publish the following "Frequency Indices of Mammal Genera in Fall and Winter Food of 191 Mustela cicognanii": Microtus, 35.7 per cent; mammals undetermined to genus but principally mice, 16.3; Blarina, 15.1; Peromyscus, 11.4; Sylvilagus, 9.0; Sorex, 4.9; Rattus, 4.4; Tamias, 3.6. Close correspondence is shown by the following data of Aldous and Manweiler (1942) for the ermine from Lake of the Woods, Minnesota: mice, 58.7 per cent by number and 54.5 by volume; shrews 22.5 and 21.8 per cent; birds, 2.7 and 5.0 per cent. Of the mice in stomachs, 40 per cent were microtines, 15 per cent were Peromyscus and 45 per cent were unidentified as to kind. Fragments of a small fish were found in one stomach. Summed up, the dominant winter foods were mice and shrews. Trapping of the mammal populations was done to see what the available food was and it was found that the small mammals were eaten in direct ratio to their relative abundance. Snowshoe rabbits and red squirrels were not eaten. The Minnesotan data were from 60 stomachs and 53 intestinal tracts recovered from 129 weasels trapped by use of scent (not bait) mostly from January 1 to February 7, 1939, although a few were trapped in 1938. Analyses of contents from stomachs gave approximately the same results as those from intestines. In 1939 at Lake of the Woods, weasels were concentrated where food was abundant but no such concentration was noted in the following winter. Big short-tailed shrew (Blarina brevicauda).—In New York State, the ermine preys on Blarina as shown by Hamilton's (1933:330) seeing one being carried by a male ermine on May 6, 1931, and another being carried by a female on May 13, 1932. The same author (1928:249) found the remains of a Blarina in a small female from Malone, New York. Kirk (1921) observed, however, that the ermine (M. e. cicognanii) avoided the shrew, Blarina, caught in a trap and that Blarina avoided the weasel caught in a trap. Chipmunk (genus Tamias).—Remains were found in a male ermine in New York on May 14, 1932 (Hamilton, 1933:330), and Seton (1929 (2):602) records a chipmunk at Lake Couchiching, Ontario, that was pursued into the water by an ermine. Deer mice (genus Peromyscus).—As shown by Hamilton (1933:33) and Aldous and Manweiler (1942), Peromyscus was second only to microtines in numerical abundance among the food items of ermines in New York and Minnesota. Peromyscus and microtine rodents were brought to a den of the diminutive M. e. muricus in early August, in Fresno County, California, according to Ingles (1942). He observed that an Alpine chipmunk was active under and around the tree and that juncos reared young 40 feet from the den but that the chipmunk and juncos were unmolested by the ermines. Lemming (genus Lemmus).—One was recovered from a female ermine (with milk in her glands) at Laurier Pass, British Columbia (Sheldon, 1932:201). Red-backed mouse (genus Clethrionomys).—Criddle and Criddle (1925:146) record that on "May 31, 1921.—Saw a Bonaparte's weasel capture a Red-backed Vole after a long hunt during which the pursuer never once lost track of its victim." Meadow mice (genus Microtus).—As shown by the data of Hamilton (1933:333) and Aldous and Manweiler (1942) recorded above, Microtus is the item of first importance in the diet of the ermine in New York and Minnesota. Criddle and Criddle (1925:146) write concerning the vicinity of Treesbank, Manitoba, that "October, 1918.—Following a severe outbreak of mice in 1916-17, Bonaparte's weasel increased enormously and very soon reduced the rodents to comparative rarity. This resulted in a scarcity of food for the weasels, which in their turn became greatly reduced in numbers." Old World rat (Rattus).—Bishop (1923) found two headless rats near a nest of this species in Albany, New York. Pika (Ochotona).—Dixon (1931:72) at Milner Pass, Colorado, on July 20, 1931, saw an ermine, of the subspecies muricus, following a three-fourths grown pika by scent and outrunning the pika. The pikas worked a relay system and the weasel abandoned the trail when the fourth pika became the object of the chase. Cottontail (genus Sylvilagus).—Hamilton (1933:33), as noted above, found remains of cottontail in the digestive tracts of ermine that had been trapped for fur in winter. Possibly these remains were bait that had been placed at traps. Snowshoe rabbit (Lepus americanus).—Morse (1939:210) in a study of predation on hares and grouse in the period of notable decimation of these two game species in 1935-1936 in the Cloquet Valley State Forest, in St. Louis County, Minnesota, found that "weasel predation on hares appeared to be of very low incidence or altogether lacking." Wild birds (Class Aves).—Aldous and Manweiler (1942), as noted above, found that the remains of birds constituted five per cent by volume of the food of the ermine in winter in Minnesota. Chicken (genus Gallus).—Criddle and Criddle (1925:145), who published relatively extensive data on the three species of weasels of Manitoba, write that: "We have no record of Bonaparte's weasel killing poultry, and we doubt whether it ever does so." However, Soper (1919:46) investigated the excited cackling of a hen brooding chicks at night and found a solitary ermine that had killed three chicks and that had the remainder under very active scrutiny. Leopard frog (Rana pipiens).—One frog was found in a male ermine on November 20, 1931, in New York by Hamilton (1933:300). Fish (Class Pisces).—Aldous and Manweiler (1942) found fragments of a small fish in one of 60 stomachs of ermine from Minnesota. Earthworm (Phylum Annelida).—Osgood (1936:64), presumably at Rutland, Vermont, observed a pair of weasels from 2:15 P.M. to 5:00 P.M., in a barn and saw the female in that time make many trips for food for her young. Only earthworms were brought. Fifty traps in an adjacent, swampy field caught only one bull frog and no mice indicating that mice had been eliminated from the foraging territory of the ermine. In handling food, Dice (1921:22) noted that the Alaskan ermine did not use the feet but only the mouth. ReproductionLitters of 4, 4, 7, 7, and 8, yielding an average of 6 young per litter have been recorded from the northeastern United States by Hamilton (1933:327). He (op. cit.:321-325) described animals one day old from New York State as being flesh-colored, having the long neck of the adult and a fine growth of white hair two milli meters in length, on the dorsal surface of the neck, that foreshadows the mane or pompadour that is prominent from the 14th to the 21st day of life. Six animals, when one day old averaged 1.7 grams in weight, which was three per cent of the weight of an adult female and one and one half per cent of the weight of an adult male. At two weeks of age the heavy brown mane stood out in marked contrast to the rest of the scantily, white-furred animal. The eyes opened on the thirty-fifth day of life. Fig. 24. Mustela erminea richardsonii, adult female, Catalogue Number 14866, U. S. Nat. Mus., Fort Chimo, Ungava. × 1/2. Ventral view of body of a pregnant female to show details of mastology. Note the five pairs of mammae characteristic of weasels, and the uneven arrangement of mammae of the two sides which is also common among weasels. Fig. 25. Map showing geographic ranges of the subspecies of Mustela erminea in the New World. For rearing their young, ermines live in burrows. Bishop (1923), in Albany, New York, found a burrow occupied by four young and a pair of adults. The burrow had many galleries and contained a nest constructed of rat fur, fine grass and fragments of leaves. At Woods Lake, Fresno County, California, in early August, Ingles observed (1942) some young and at least one adult at their den which was in a burrow beneath a hollow tree. The ermines used the hollow root and the hollow tree as well as the burrow beneath. Seton (1929 (2):591) quotes S. Eldon Percival, of Barretts Rapids, Ontario, as finding the living quarters of an ermine in unthreshed grain stacked in a barn and says (op. cit.:590) that John Burroughs dug out a nest, composed of leaves and the fur of mice and moles, two or three handfuls in bulk, from a cavity the size of a hat, arched over with a fine network of tree roots. Four instances in which the male as well as the female was present at a den containing young are cited by Hamilton (1933:328) and he gives some evidence, although not at all conclusive, that "adults customarily pair, or at least run together, at times other than the breeding season." No other writers remark on this matter. I doubt that adult ermines are associated in pairs for most of the year but such may be the case. Mustela erminea arctica (Merriam)Ermine Plates 2, 3, 4, 9, 10, 11 and 41
Cranial differences from Mustela erminea kaneii (which occurs on the Asiatic side of Bering Strait), in both males and females, are: larger size relatively as well as actually, broader except in mastoidal region where relatively (to basilar length) the width is less; preorbital part of skull broader as well as longer. From kadiacensis differences in the skull of the male are: size less; 13 per cent heavier, relatively (to basilar length) narrower across interorbital region and zygomatic arches; tympanic bullae relatively as well as actually narrower. Judging by the single available adult female of kadiacensis, the skull of female arctica is larger in all parts measured, a fourth heavier, has tympanic bullae of almost twice the volume and the interorbital and preorbital regions, relative to the braincase, are much reduced in whatever plane measured. Differences from richardsonii, additional to those noted above in the formal description of the skull, between the males, are: larger in all parts measured except length of tympanic bulla which is about the same; 42 per cent heavier; relative to basilar length, skull broader with preorbital part longer as well as broader; tympanic bullae more inflated posteriorly. The same differences prevail between females except that the skull is 36 per cent heavier and in arctica the length of the bulla is actually more (although relative to the basilar length less) and its greater inflation posteriorly is hardly perceptible. Differences from alascensis, additional to those indicated in the formal descriptions of the skulls of the two, in males, are: larger in every part measured; 95 per cent heavier; relative to the basilar length, skull broader with preorbital part longer as well as broader; measured at a point opposite the foramen lacerum anterius, the width of the pterygoid space is more, rather than less, than 40 per cent of its length. Excepting this difference in width of interpterygoid space, the same differences prevail between females, those of arctica being 56 per cent heavier. Comparison with semplei is made in the account of that subspecies. Skull indistinguishable from that of polaris. Remarks.—The person who studies specimens of this subspecies finds labels inscribed with the names of naturalists well known to all readers of literature on the Arctic. Sir John Franklin, R. McFarlane, R. Kennicott, E. W. Nelson and R. M. Anderson are names which appear commonly. Of Alaskan specimens prepared according to modern methods, a large share was obtained by O. J. Murie and L. R. Dice. The ermine was observed in the far north by early explorers and was mentioned in the literature, almost always under the name then used for the ermine of northern Europe and Asia. In 1896 Bangs misapplied to it the name richardsonii but Merriam in the same year corrected the application of this name and proposed as new for this weasel the name arctica, the name in use today. For almost 50 years after Merriam and Bangs wrote about it, arctica was treated, nominally at least, as a species distinct from its other relatives in both the Old- and New-World. The subspecific status of arctica was emphasized in 1944 (555) by the present writer in reporting in detail upon the specimens, of Mustela erminea, from Eastern Asia which were made available on loan by Professor B. S. Vinogradov and the late Anatol I. Argyropulo of the Leningrad Academy of Sciences. Specimens of Mustela erminea kaneii from the Asiatic side of Bering Strait and Mustela erminea arctica from the American side are distinguishable by slight cranial characters but in coloration and external measurements I can detect no differences. Merriam's (1896:16) mention of more golden-colored upper parts and darker underparts in American specimens than in erminea was the result of his comparison of Alaskan and northern European specimens. When Old World specimens from eastern Siberia, instead of from Europe, are used the differences mentioned by Merriam do not apply. Incidentally, many Siberian specimens have the white border, on the ear, which Merriam (loc. cit.) noted as a distinguishing feature of arctica. When Merriam named arctica he said (1896:15, 16) "Putorius arcticus ... has heretofore been confounded with erminea or richardsonii.... It is interesting to find in this country an Arctic circumpolar weasel which, though specifically distinct, is strictly the American representative of the Old World erminea." Bearing in mind that Merriam's concept of species and subspecies (see Merriam, 1919:6) differed from that of nearly all modern systematists it is clear from his statement quoted above that he correctly understood the zoÖlogical relationship obtaining between the ermines of the Old and New Worlds. Ognev (1935:31) seems to have been the first to use the name combination Mustela erminea arctica for Alaskan specimens. Thereby he expresses the view adopted here, namely that the American ermine is subspecifically but not specifically distinct from the Old World animal. Whether actual intergradation (crossbreeding) ever takes place across the narrow Bering Strait I do not know. I doubt that crossbreeding occurs but considering the Diomedes (islands), that might serve as a half way stopping point, and remembering Mr. Charles Brower's oral statement to me that he had seen tracks of ermine as far as 10 miles from the northern shore of Alaska out on the ice, the possibility must be granted of an occasional individual crossing from one side to the other of Bering Strait on the ice in winter or of being carried across when the ice broke up and drifted. If transfers of this kind occurred often one would expect ermines to occur also on Saint Lawrence Island where apparently they do not. The one skin (U. S. Nat. Mus. no. 259046) seen as labeled from there, my friend, Otto William Geist ascertained was imported as a skin with other furs from Siberia. Ognev (op. cit.) who used the name combination Mustela erminea arctica for Alaskan specimens, applied it also to animals from Kamchatka. At the same time he recognized the animal from the eastern mainland of Siberia (as opposed to the peninsula of Kamchatka) under the name Mustela erminea orientalis Ognev 1928. Hall (1944:556) applied the earlier proposed name Putorius kaneii Baird 1857, to the animal on the eastern mainland of Asia and proposed the new name Mustela erminea digna for the ermine of Kamchatka. In comparing material of these two Asiatic races with topotypes and other specimens of M. e. arctica from Alaska, it seemed to me that the degree of relationship, one with the other, was about the same. M. e. digna has a slightly larger preorbital region than M. e. kaneii, and the skull is longer. In both of these particulars digna approaches closer to arctica. M. e. kaneii has longer tympanic bullae and a wider skull than digna and therein approaches more towards arctica than toward digna. As nearly as I can make out, digna and kaneii show a nearly equal degree of resemblance to arctica. Also the degree of difference between digna and kaneii is about the same as between either one of them and arctica. In view of the above considerations the ermines of the New and Old worlds are here regarded as only subspecifically distinct. In the original description of Putorius audax (here regarded as inseparable from Putorius arcticus Merriam) Barrett-Hamilton erroneously designated the type locality as "Discovery Bay, North Greenland" whereas he should have written Grinnell Land [= Ellesmere Island of modern terminology] in place of Greenland. As reference to Nares (1877 and 1878) will readily reveal, Discovery Bay is near 65° W and 81° 40´ N, across Robeson Channel, to the west, from Greenland. The label on the type specimen and the specimen register in the British Museum of Natural History each designates the locality for this specimen, the type of audax, as Discovery Bay without mention of Greenland. The published accounts of Feilden (1878) and Nares (1877 and 1878) state that specimens of ermine were obtained at Discovery Bay. Probably H. C. Hart is the collector of the specimen; he was the naturalist attached to H. M. S. Discovery which wintered at Discovery Bay while H. W. Feilden was the naturalist attached to H. M. S. Alert which wintered a few miles southeast of Cape Sheridan, also on the eastern coast of Ellesmere Island. It is true that from these ships a trip was made into Greenland and an ermine (only one individual it seems) was obtained there, but this individual was the type specimen of Mustela erminea polaris, in the account of which race something of the history of this specimen is given. With the material available—and it is not entirely adequate—I can detect no features by which animals from the type locality of audax can be distinguished from typical arctica which latter name has priority. Intergradation with richardsonii probably occurs completely across the continent. Intergrades here referred to arctica include those from Fort Goodhope. The one defective specimen from Lake Lebarge, Yukon, is not certainly identified as arctica and how far west of Teslin Lake the boundary-line between arctica and richardsonii should be drawn remains to be ascertained. The one specimen available from Hinchenbrook Island, no. 912 Mus. Vert. ZoÖl., an adult female, is doubtfully referred to arctica because the damaged tympanic bullae appear to be no larger than in alascensis, and the size of the skull is more as in alascensis although intermediate between that race and arctica. Shape of the skull is more as in arctica. Possibly more nearly adequate material would show the existence on Hinchenbrook Island of an insular race differing in about the same degree from arctica of the mainland as does the insular kadiacensis. Nevertheless, the males from farther south at Cape Yakataga are in all respects arctica and this argues against near relationship to alascensis of the animal on Hinchenbrook Island. The three animals seen from Yakutat Bay are so young as not to display clearly the cranial characters of the subspecies but the extension of the color of the underparts onto the underside of the tail in them and also in the skin without corresponding skull from Glacier Bay, Alaska, is as in arctica, the race to which they are referred, and gives substantial basis for showing the geographic range of arctica as extending this far south along the Pacific Coast.
Mustela erminea polaris (Barrett-Hamilton)Ermine
To me the skull of polaris is indistinguishable from that of arctica. Therefore the comparisons made of the skull of arctica with those of other subspecies will apply also for polaris. Remarks.—In view of the heretofore erroneous assignment of the type locality of Mustela erminea audax to Greenland, pains were taken to verify the statement by Barrett-Hamilton (1904:393) relative to the type specimen of polaris. Taking pains thus seemed the more worthwhile because in the specimen register at the British Museum of Natural History, there is written to the right of catalogue numbers 78-6 = 19 nos. 1-11, "Discovery Bay Presented by Mr. Hart Arctic Collection." This refers to no. 78.6.19.1. There are no ditto marks below but by implication this data applies also to nos. 1-11, which include the holotype of polaris. A label attached to the specimen does however give the locality as "Hall Land" "N Greenland" and another label has on it "Ermine, procured by Mr. Beaumont Greenland Lat 89° Long W 59-20." The 89° is obviously a mistake (on the label or in my transcription of it) for 82°. Reference to Nares (1877:385) reveals that Lieutenant Lewis A. Beaumont, under date of June 15 and 16, 1876, wrote in his field journal as follows: "I shot an ermine." In the daily accounts of his journey from Discovery Bay on Grinnell Land [= Ellesmere Island], across Robeson Channel and along the north coast of Greenland to the west base of Mount Farragut near 50° 30´ W he mentions the ermine only this once. For several other kinds of animals, Beaumont mentions individuals seen or shot, often with the notation that this is the second, or third seen. This mention of a kind of animal whenever seen was in accordance with orders. On page 39 of the Discovery Report (op. cit., 1877) in "General orders to sledging parties" by Captain G. S. Nares, Commanding the Expedition, we find "... note daily: IV State the animals seen and those shot." Reference to the map facing page 358 of the (op. cit.) report reveals that on the 15th and 16th, camps were made by Beaumont in Gap Valley, each 7-3/4 miles northeast of Cape Brevoort, one camp on either side of the 82° line, and separated from each other by a distance of only 2-1/4 air line miles or 4-1/2 miles march according to his journal. These several data, then, are the bases for designating the type locality of M. e. polaris, in the way that I have stated it at the beginning of this account of the subspecies. The light-colored upper parts and more intensely yellow underparts well differentiate this subspecies from arctica or semplei. Intergradation is suggested by a skin, no. 1462, Copenhagen Zoological Museum, from Axel Heibergs Land, the color of the underparts of which agrees with that of specimens from Greenland. Also the color of the upper parts is decidedly nearer that of animals from Greenland than to that of specimens from Ponds Inlet, Tulican and Gifford River. No other specimens west or south of Greenland suggest intergradation. In Greenland itself, one adult, a female from Turner Sund, East Greenland, has the underparts no more yellowish than in some specimens from Melville Peninsula. This female is darker on the back than any one of the other 10 specimens from Greenland in summer pelage examined at the same time, but even so is not so dark colored as animals from Baffin Island or other islands to the west of Greenland. The final summation of information about this subspecies would have been more precise if I had been able to have actually in hand, at the time of writing, specimens preserved in the Copenhagen Zoological Museum. The war made it impractical to secure the loan of these as previously planned. Even so, the measurements and notes on color that I obtained from this material, in 1937, in Copenhagen, suffice to prove that the subspecies polaris is well set off in color from the other American subspecies of Mustela erminea. The best material of this subspecies is in the University Zoological Museum at Copenhagen, Denmark.
Mustela erminea semplei Sutton and HamiltonErmine
In comparison with richardsonii, the skulls of males averaged smaller in every measurement taken except breadth of rostrum and interorbital breadth which are more, and zygomatic breadth and length of inner lobe of M1 which are approximately the same; skull about 20 per cent lighter; in relation to basilar length, preorbital region longer and broader in every part measured. Female averages larger, in every part measured; 23 per cent heavier; in relation to basilar length, every other measurement more. It is noteworthy that the skull of the male is smaller and the skull of the female larger than in richardsonii. Differences from arctica are: Size less, in each sex; males about 40 per cent and females 10 per cent lighter; in males, skull more rounded in outline as viewed from above because zygomatic arches arise less abruptly from skull; in males tympanic bullae do not project so far ventrally from squamosal floor of braincase; with these exceptions, skull of semplei can be said to be a smaller edition of that of arctica. From polaris, semplei differs, cranially, in the same way as from arctica. Remarks.—There is a slight increase in size of ermines toward the north which probably is the result of intergradation between semplei and arctica. Specimens from the northern part of Baffin Island are larger than those from farther south. Specimens from the mainland west of Southampton Island may owe their smaller (than in arctica) size to intergradation with richardsonii almost as much as to intergradation with semplei. DegerbØl's name Mustela arctica labiata was applied to specimens, which to me are indistinguishable from topotypes of Mustela arctica semplei, which latter name has three years priority. DegerbØl (1935:34) states that Malugsitaq, Melville Peninsula, is the type locality. He did not designate a type specimen. Reference to his account (op. cit.:26) shows that he lists five specimens from the type locality, or more precisely as "Malugsitaq, Lyon Inlet. 5 summer skins. ? ? June-July 1922. P. F., CN. 2262-2266." On labels attached to these specimens, "Lyon Inlet" is replaced with "Melville Peninsula." On July 28, 1937, DegerbØl and I together examined these specimens in his laboratory. Because no. 2262 is first mentioned I regard it as the type. It is a juvenal male, skull and skin, no. 2262 (20.5 1931.8), Univ. Zool. Mus. Copenhagen, obtained in June or July of 1922 by Peter Freuchen whose original number was / s 2324. The specimen is one of 5 males taken at the same locality by the same collector and they bear identical data as to date. They look to be of the same litter for all are roughly of the same size and each retains milk teeth. Additional females, with external measurements carefully taken, are much needed from Southampton Island, because the available females are insufficient to show the degree of sexual dimorphism. If the meager data available be accepted, the difference in size between the two sexes is less than in other subspecies. My own feeling is that a better sample of females would show the secondary sexual difference in size to be more than available data indicate.
Mustela erminea kadiacensis (Merriam)Ermine
Comparison with arctica has been made in the account of that subspecies. Although richardsonii and kadiacensis are described as having the zygomatic breadth less than the distance between the last upper molar and jugular foramen, the zygomatic breadth is considerably more in kadiacensis than in richardsonii; consequently the two dimensions are more nearly equal than in richardsonii. Except for being slightly narrower, the skull of kadiacensis is only a slightly smaller edition of that of arctica. Remarks.—When naming the weasel from the mainland of Alaska as new, under the name Putorius arcticus, Merriam (1896:16) wrote: "A small form of arcticus occurs on Kadiak Island.... It is probably worthy of recognition as subspecies kadiacensis." The informality of this description possibly was in part due to the describer's recognition of the fact that the degree of difference between arcticus and the insular kadiacensis was slight. Specimens collected after Merriam proposed the name for the weasel of Kodiak Island show the animal there to be less different from arctica of the adjacent mainland than he thought; small size is the most pro nounced distinction of kadiacensis and Merriam's male type specimen is smaller than any of the five additional males saved from Kodiak Island since that time. Even so the differences fully warrant subspecific recognition, in my opinion, although kadiacensis is not a strongly differentiated race. More adult females are needed to ascertain the norm of form and size for that sex. If the one female known is typical, the difference from arctica is more pronounced in females than in males. The lesser size of kadiacensis can hardly be credited entirely to the effect of insularity, for animals from the southern part of the mainland, on Kenai Peninsula for example, are smaller than those from central and northern Alaska and provide evidence of intergradation of a sort between kadiacensis and arctica.
Mustela erminea richardsonii BonaparteErmine
Comparison of the skull with that of arctica, polaris, semplei, kadiacensis, haidarum, cicognanii, bangsi, invicta, fallenda, and alascensis is made in the accounts of those subspecies. Remarks.—M. e. richardsonii has the most extensive geographic range of any American race of erminea, is centrally located with respect to the other races, is more abundantly represented by study specimens in zoÖlogical collections than any other race, and is a sort of average for the species as a whole in most structural features. Therefore richardsonii is used as a standard of comparison and accordingly is more fully described than any one of the other races each of which by reference to richardsonii is described in comparative fashion. This comparative description has the virtue of more clearly indicating differences between subspecies and also makes for brevity. John Richardson, Bernard R. Ross, and names of their companions, as written on the labels of the older specimens recall to the student's mind early explorations of the north country. Edward A. Preble obtained important specimens at several places and in recent years J. Kenneth Doutt and G. G. Goodwin have made the reviser's work easier by preparing specimens in series from areas not previously well represented. The nomenclatural history of this subspecies begins with references in the literature that identify the animal as the Old World species, Mustela erminea—an identification which the study here reported upon shows to have been correct in the specific, although not in the subspecific, sense. Richardson, for example, in his "Fauna Boreali-Americana" published in 1829 so identified the animal. In 1838, Bonaparte, basing his description on Richardson's account of 1829, proposed the new name richardsonii. Richardson himself, the following year in the "Zoology of Beechey's Voyage," accepted Bonaparte's name and it has been applied to the animal in the central part of the northern timber-belt of North America ever since, except as authors used the name Mustela erminea in the belief that richardsonii was not distinct from erminea. The north and south boundaries of the range assigned to richardsonii varied according to the notions of the particular writer who was employing the name. Until Merriam in 1896 named arctica as distinct, animals from the far north were generally included under the name richardsonii along with populations to which the latter name now is applied. Because richardsonii grades gradually into the smaller cicognanii of more southern occurrence the boundary between the two has been set farther north by one writer and farther south by another, depending probably upon what the writer felt was the halfway point in size. This point of course depended upon the samples selected as typical of richardsonii on the north and cicognanii on the south. Because Bangs, in 1896, took as representative of richardsonii the far northern and hence large-sized animals (now separated as M. e. arctica), his halfway point in size between them and the small cicognanii of New England naturally fell farther north than it would have had he used as representative of richardsonii specimens from places south of the range of arctica. In 1903 J. A. Allen proposed the name Putorius microtis for a specimen from Shesley, northwestern British Columbia, a place approximately 50 miles northwest of Telegraph Creek. Considering the great disparity in size between this one specimen and the other larger specimens of normal size, from the general region, available to Allen at that time, it is not surprising that he thought two full species were represented. In 1943 when G. G. Goodwin called to my attention two males, as small as the type of microtis and taken by him approximately 300 miles east of Shesley, in the valley between the Musqwa and Prophet rivers, I for a second time examined all available specimens and data with the possibility in mind that microtis was a species or subspecies distinct from M. e. richardsonii, but again concluded that only one subspecies was involved because no character except size was found to distinguish the large from the small individuals of a given sex and there are, preserved from northern British Columbia, individuals of intermediate size. Putorius microtis Allen seems to have been based on an individual of M. e. richardsonii near the lower limit of size for that subspecies and microtis is regarded as a synonym. Barrett-Hamilton in 1904 named the animal at "Fort Simpson, British Columbia" Putorius arcticus imperii. Preble (1908:232) pointed out that Fort Simpson on the Mackenzie undoubtedly was the place intended, and arranged imperii as a synonym of M. e. richardsonii. The type specimen of imperii was stated to have been received from B. M. Ross who is known to have collected specimens, including specimens of this species (now in U. S. Nat. Mus.), at Fort Simpson on the Mackenzie. I know of no Fort Simpson in British Columbia. If, as seems improbable, Port Simpson, British Columbia, was the place that Barrett-Hamilton intended to designate (where so far as I know Ross did not collect), the name imperii still would seem to be a synonym of richardsonii because richardsonii seems to be the race of weasel at Port Simpson. In proposing the name Putorius arcticus imperii, Barrett-Hamilton stressed that the weasel, which he was naming, was a subspecies of P. arcticus, gave characters which applied perfectly to richardsonii but made no reference to richardsonii. Barrett-Hamilton did not refer to richardsonii possibly because he relied on Merriam's classification of 1896 wherein richardsonii is treated as a species distinct from arctica. Merriam, it will be remembered, held that slight degree of morphological difference rather than intergradation was the criterion for subspecies. Although I have no record of having examined the type specimen of imperii I have but little hesitancy in treating it as a synonym, and would have no hesitancy at all in so doing if the type was certainly known to have been obtained at Fort Simpson on the Mackenzie. The name Mustela cicognanii mortigena Bangs, 1913, proposed for the ermine of Newfoundland, is placed as a synonym of richardsonii only after repeated, detailed comparisons. In advance of study I supposed that the isolation of the ermine, in Newfoundland, had contributed to its differentiation, which, however, the original describer, Bangs, indicated was slight. Bangs was a careful worker and I am confident that the differences he described really existed between his specimens. Material more nearly adequate than he had from the mainland, shows the males, so far as my measurements and comparisons go, to be in nowise different from those in Newfoundland. Females in Newfoundland may have, on the average, slightly longer hind feet than on the opposite mainland but I am not certain that they do and even if there is a slight difference in this regard as suggested by available data, I think it insufficient basis, alone, for according subspecific status to the insular animal. The name richardsonii was based by Bonaparte on Richardson's description which in turn was drawn from a specimen taken at Fort Franklin, that thus becomes the type locality. It is fortunate that Preble, in 1903, succeeded in taking specimens there because the place is near the belt of intergradation between arctica and richardsonii. Of Preble's two adult males (see Preble, 1908:232) I have examined no. 133847, which is in transitional pelage and therefore gives no clue in so far as coloration is concerned, as to affinities with arctica versus richardsonii. Specimens in the summer pelage are much to be desired from Fort Franklin. Regardless of what their coloration may be, specimen no. 133847, in external measurements and most certainly in cranial features is of the race to the south and not the race that Merriam named arctica. Because all specimens from localities to the south of Fort Franklin likewise differ from arctica of the barren grounds, considerable additional confidence is felt in allocating the name richardsonii to the animal which ranges from Fort Franklin southward rather than to the one, here designated arctica, that occurs to the northward of Fort Franklin. Although in most structural features richardsonii is a sort of average for the American races of the species, it is the extreme in high degree of sexual dimorphism. The difference in size between the males and females is greater than in any other race except possibly M. e. kadiacensis in which so little is known of the female that the difference between the two sexes cannot be accurately judged. It will aid in understanding the high degree of secondary sexual difference in richardsonii to visualize two kinds of weasels distributed over the northern half of the continent, thinking now of the geographic area in America occupied by the whole species Mustela erminea of which the subspecies richardsonii is only a part. One of the two kinds of weasel is the male ermine and the other the female. The decrease in size of the male, as measured by the weight of the skull, is in the ratio of 7 in the north to 2 in the south. This decrease is gradual whereas the corresponding decrease from 3 to 1 in the female is not gradual; half of the decrease in the female occurs in the short north to south distance comprised in the belt of intergradation, along the northern boundary of richardsonii, between it and arctica. As a result richardsonii is composed of females with medium sized skulls and males with relatively large skulls, the ratio by weight being approximately 5 to 2. The disproportion in races of ermines both to the north and to the south is less. Actually in the north (arctica) the approximate ratio by weight is 2-1/3:1; in richardsonii, 2-1/2:1; in the south (muricus), 1-2/5:1. Indicated in still another way in richardsonii the skull of the female is 56 per cent lighter than that of the male and the skull of the male is 127 per cent heavier than that of the female. Intergradation with races whose ranges border on that of richardsonii is complete. On the northern boundary of the range of richardsonii along the western shore of Hudsons Bay for perhaps a hundred miles north of Eskimo Point, there are intergrades with arctica. As judged by their lesser size, individuals of this population are influenced by the semplei-stock. Otherwise, intergradation on the northern boundary, with arctica, is abrupt whereas intergradation at the south, between richardsonii and cicognanii, is gradual. Intergradation is similarly gradual between richardsonii on the one hand and bangsi and invicta on the other. By speaking of the intergradation as abrupt, it is intended, in this instance, to indicate that in a relatively narrow belt, between the geographic ranges of arctica and richardsonii, ermines intermediate in color-pattern, shape of skull, and size, bridge the gap between the ermine of the tundra (arctica) and that in the forest belt (richardsonii). It may be added that the degree of difference between the two subspecies just mentioned is approximately twice as much as between richardsonii and cicognanii. The intergradation between cicognanii and richardsonii is gradual. By gradual it is meant that the change from one kind to the other is achieved in a wider area where ermines from locality A do not differ appreciably from those taken at, say, locality B, 50 miles farther south, although ermines from A and those from a third locality, C, say, 130 miles south, clearly show differences indicative of geographic variation.
Mustela erminea cicognanii BonaparteErmine
The skull of the male, in linear measurements, is approximately 13 (12-16) per cent smaller and 40 per cent lighter than in M. e. richardsonii. In relation to the basilar length, the skull averages slightly narrower, slightly shallower as measured in the vertical plane touching the posterior borders of the last upper molars, and the preorbital part is slightly longer. In skulls of females of cicognanii, linear measurements average 3 (0-6) per cent less, the weight is 16 per cent less and the teeth are 5 per cent shorter. In relation to the basilar length, measurements of the skull are approximately the same or slightly less in cicognanii. In comparison with bangsi, the male sex in linear measurements of the skull and teeth averages 11 per cent less than in bangsi from Aitkin, Minn., and 6 per cent less than in bangsi from Elk River, but in relation to the basilar length the preorbital region is larger. The weight is approximately a fourth less. In females the measurements average less, some being the same, and in relation to the basilar length, the bullae are shorter and the skull is shallower. The weight is about the same. Remarks.—In January, 1838, in Charlesworth's Magazine of Natural History, C. L. Bonaparte proposed for three kinds of American weasels the names Mustela cicognanii, Mustela richardsonii and Mustela longicauda. In this paper Bonaparte indicates that he previously had written (for his Iconografia della Fauna Italica ...) an account of Mustela cicognanii using this same name. Fasciola XXII of the Iconogr. d. Fauna Italica, presenting his account of Mustela, like the English paper was published in the year 1838. In his article in Charlesworth's Magazine, Bonaparte refers to his book published [used the past tense] in Rome but whether it actually appeared first I am unable to determine and hence am uncertain which of the two constitutes the original description. Reference to the Italian account suggests as basis for the name M. cicognanii, (1) specimens possibly seen in the United States by Bonaparte, or (2) Godman's published account of the animal. In the English publication, however, Bonaparte actually says that (1) he saw the small species in the Union [= United States]. Also, he (2) mentions his earlier written Italian account, (3) mentions that "all the [American?] naturalists" used the name M. vulgaris for this animal, (4) incidentally mentions Godman's account, and (5) in naming two other American species cites accounts of them by Richardson. Also, Bonaparte in this English article makes clear that when he wrote [not necessarily published] his Italian paper he did not know of the existence of two of the three American species. In the register of mammals at the British Museum of Natural History, there appears: 43.3.3.3 Mustela longicauda Bonap N Amer. presented by Dr. J. Richardson To the right of these entries there appears, in three lines, the notation: "The three specimens examined by Prince Canino on which he established the three species." Every part of each of the above entries is in the hand writing of J. E. Gray, in charge of the collections from 1824 to 1840 and associated with them as Keeper until 1875. The three specimens are in good condition considering their age. The catalogue or register number shows, among other things, that they were entered in the register on March 3, 1843. Questions which might occur to anyone are: (1) Was there a type specimen of Mustela Cicognanii Bonaparte? If so is it no. 43.3.3.5? (2) If there was no type specimen was there a type locality? If so what is it? Among other things that may have bearing on these questions, are these: Bonaparte in Charlesworth's Magazine appears to base the two names Mustela Richardsonii and Mustela longicauda on Richardson's published account of Mustela erminea. At any rate immediately following each of the two names, Bonaparte writes "Nob. (M. erminea Rich. F. Bor. Amer.)." Bonaparte's other, first newly proposed name, Mustela Cicognanii, in Charlesworth's Magazine has following it only "Nob. North America," although in a paragraph above he did point out that this was the animal which all naturalists, at the time he was in America, considered as M. vulgaris. Turning to Richardson's account (Fauna Boreali Americana, ... Quadrupeds, pp. 45-47. 1829) one finds that he recognized two species, M. vulgaris and M. erminea. Of the first he gives measurements "of an old female killed at Carlton House." Of the second species he distinguishes two varieties, the first represented by a specimen, of which he gives measurements, "killed at Fort Franklin, Great Bear Lake" and, the second variety "of a larger size, having a longer tail and longer fore-claws" he indicates the size of by giving measurements of a specimen taken "in the neighborhood of Carlton House." The last variety is clearly the basis of Bonaparte's M. longicauda. The specimen from which Richardson took his measurements I have been unable to locate [no. 43.3.3.3 in the British Museum, appears to be another specimen, although of the same subspecies and provided by Richardson]. The first variety of Richardson's Mustela erminea, clearly is the basis of Bonaparte's M. Richardsonii. The specimen from which Richardson took his measurements may well be no. 43.3.3.4 now preserved in the British Museum of Natural History, but I could not be certain about this. Richardson's M. vulgaris is accompanied by measurements of a female which I have ascertained to my full satisfaction is the identical specimen now bearing catalogue number 43.3.3.5 said by Gray to be the specimen on which Bonaparte based his name Mustela cicognanii. Gray probably saw his guest, Bonaparte, at work on these weasels and Gray's own written indication perhaps should be accepted at its face value. I found only 4 Richardson specimens of North American weasel in the British Museum in 1937 and it is conceivable that Bonaparte, 100 years before, actually had at hand only one specimen each of two kinds and 2 specimens of the third. This I think is not an important consideration, though, for Gray says just which specimens did serve as basis for Bonaparte's names and there is only one specimen for each name according to Gray. But I wonder if a type specimen can be made in this way? That is to say, after a name is published in a manner which makes it available, and if two or more specimens of the kind of animal involved, were, or may have been, available to the describer, can a person, even the author, himself, make a type specimen by saying that one particular specimen is beyond doubt the specimen on which a given name was established even though no particular specimen was designated in the original description? I incline to the view that a specimen so designated would at most be only a lectotype, unless it were a cotype. However, if a holotype can be made by action such as Gray took, then (1) is no. 43.3.3.3 the type specimen of Mustela longicauda Bonaparte and, (2) is no. 43.3.3.4 the type specimen of Mustela Richardsonii Bonaparte? Incidentally, Mustela longicauda Bonaparte whether based on no. 43.3.3.3 or on Richardson's account will continue in its present application. The same is true of Mustela richardsonii. If the basis of Mustela cicognanii Bonaparte [the diagnosis in the Iconografia d. Fauna Italica ... makes it clear that the name applies to the short-tailed species] was a weasel from the eastern United States or a description of a weasel or weasels from there, the name will continue in its present application. If, instead, the name is based on no. 43.3.3.3 (from Carlton House, Saskatchewan) or on Richardson's account of M. vulgaris, the name will apply to a different subspecies (now called richardsonii and richardsonii will fall as a synonym of cicognanii) and the ermine of the eastern United States will take the next available name. Bonaparte probably named (in manuscript at least) cicognanii before he ever saw the specimen in the British Museum. This is indicated by his statement in Charlesworth's Magazine (1838:37) that "I have now [Italics mine] found two [other] American species...." Whereas the names richardsonii and longicauda are based on Richardson, the name cicognanii, even if it dates from the account in Charlesworth's Magazine, appears to have a composite basis composed at the very least of (1) animals seen by Bonaparte in the United States, and (2) those called vulgaris by some other authors. Conceivably the specimen no. 43.3.3.3 in the British Museum, was part of the basis. From the nature of the case it can be argued that there could be no type and that if someone should bring to light a specimen in, say, Philadelphia, bearing the notation "this is the specimen seen in the United States by Bonaparte" it would immediately become as important as the one in London. Any American weasel or weasels (then alive or preserved in a zoÖlogical collection) that Bonaparte saw in the United States probably were of the eastern United States. Bangs (1896:18-21), for one, previous to the present consideration of the name cicognanii, restricted it to the ermine of the eastern United States. Consequently, the name cicognanii, in the present account is applied to the ermine of the eastern United States. In my opinion there was and is no type. Almost certainly there was no type if the Fauna Italica appeared before the account in Charlesworth's Magazine did.
Mustela erminea bangsi HallErmine
From richardsonii, topotypes of bangsi differ in that cranial measurements in males are approximately 7 (5-9) per cent less, linear measurements of teeth are 10 (9-11) per cent less and the skull is a fifth lighter. In relation to basilar length the tympanic bullae of bangsi are longer. Skulls of females are individually indistinguishable, those of bangsi averaging approximately 1 per cent less in linear measurements. Comparison with the smaller cicognanii is made in the account of that subspecies. Remarks.—Before the subspecific name bangsi was proposed, individuals of this subspecies ordinarily were recorded in the literature as Mustela cicognanii. The best single lot of material is in the zoÖlogical collection of the University of Wisconsin. The late naturalist Albert Lano preserved a large share of the material from Minnesota. The large series from Elk River of that same state was mostly collected by Bernard Bailey although his Aunt, Anna (Bailey) Mills, and her brother the late Vernon Bailey, at an earlier time saved some specimens from Elk River. The name bangsi was proposed in recognition of the superior work done on American weasels by the late Outram Bangs. From the range of M. e. invicta in the Rocky Mountains, that of bangsi is separated by the Great Plains from a large part of which region the species is unknown. M. e. bangsi differs from invicta in greater degree of sexual dimorphism in size, and in each sex by larger size, narrower light-colored underparts, and deeper braincase as measured at the anterior margin of the basioccipital. In bangsi the braincase is deeper relative to the length of the skull as well as, of course, actually deeper. Of the two subspecies whose ranges do meet that of bangsi, it more closely resembles richardsonii than cicognanii. From richardsonii, especially from southeastern populations of the same in which the skull is of the same size as in bangsi, the latter differs in longer hind feet. This is an average difference and by one interpretation the animals here referred to bangsi might be lumped with some of the populations from the southeastern part of the range of richardsonii and the whole lot treated as intergrades between richardsonii and cicognanii. Nevertheless, the animals here referred to bangsi are not geographically intermediate between richardsonii and cicognanii and this consideration had much to do with the decision to recognize as a separate subspecies the animals here named bangsi. Within the range of the subspecies there is some geographic variation; the hind feet of animals from Iowa average slightly shorter than those of animals from Minnesota and Wisconsin but are nowhere nearly so short as in cicognanii at the same latitude in the eastern United States. It is noteworthy that the few specimens seen from Isle Royal have the long hind feet of bangsi and not the short hind feet of cicognanii which occurs all along the northern mainland. Because an oft cited record of occurrence even though erroneous, has a way of being repeated in later works, attention is here called to the alleged occurrence of this ermine in northwestern Ohio at New Bremen. Henninger (1921:239) published the original account of the supposed occurrence but as I pointed out in 1937 (p. 304), the specimen concerned proved upon examination to be a female of Mustela frenata noveboracensis. Henninger was misled probably by the short tail; the end of the tail had been lost and healed over before the animal's death. The present study has revealed that M. erminea everywhere east of the Cascade Mountains assumes a white winter coat. Had this been known when Henninger obtained his specimen he probably would not have wrongly identified the animal from New Bremen which was in the brown, winter pelage.
Mustela erminea invicta HallErmine Plates 2, 3, 4, 9, 10, 11 and 41
From fallenda, invicta differs in that the skull of the male has a relatively narrower rostrum and relatively shallower braincase. Females show the same differences but the degree of difference is about as great again as in males. The teeth are almost exactly the same size in the two subspecies. The weight is the same in males but in females invicta is 18 per cent heavier. From streatori, invicta differs in that males average larger in every measurement taken except that the anteroposterior diameter of the inner moiety of M1 is less; 36 per cent heavier; linear measurements of the skull are about 5 per cent larger and those of the teeth, with the one exception noted, about 6 per cent larger; relative to the basilar length the tympanic bullae are longer and the rostrum is relatively narrower. In females, measurements of the skull average 8 per cent more and those of the teeth 7 per cent more except that, as in males, the inner lobe of M1 is actually shorter. Females of invicta are 12 per cent heavier; relative to the basilar length the skull is narrower throughout and the tooth-rows are shorter than in streatori. From gulosa, invicta differs in that males average larger (about 12 per cent) in every measurement taken, excepting the anteroposterior diameter of M1 which is the same; 50 per cent heavier; relative to the basilar length the length of the tooth-rows and interorbital breadth are less. In females the inner lobe of M1 is smaller but every other measurement taken of the skull and teeth is more, invicta averaging about 8 per cent larger and 22 per cent heavier; relative to the basilar length, the tooth-rows are shorter and the skull is narrower interorbitally, through the rostrum and across the zygomata. From murica, invicta of corresponding sex differs in being larger in every measurement taken; males average 17 per cent larger in cranial measurements, 13 per cent larger in dental measurements and are 83 per cent heavier; corresponding percentages for females are 11, 9 and 20. Exception must again be made for the anteroposterior diameter of the inner lobe of the last upper molar which is less in females, and only slightly more in males. In males of invicta the tympanic bullae are longer in relation to the basilar length. From the geographically remote cicognanii, skulls of both males and females of invicta are to me individually indistinguishable. There is, nevertheless, an average difference not apparent to the eye between skulls of males. If the length of the tooth-rows be taken as a standard (100 per cent), the rostrum, of invicta, as measured across the lacrimal processes is broader (89 rather than 84 per cent) but the width across the fourth upper premolars is less, 94 rather than 97 per cent of the length of the tooth-rows. Since the skull of invicta closely resembles that of cicognanii, it follows that invicta differs from richardsonii and bangsi in about the manner described in the account of cicognanii. Remarks.—Animals of this subspecies in advance of the present study generally were recorded in the literature under the name Mustela cicognanii. The difficulty in distinguishing individual specimens of invicta on morphological grounds from those of the geographically remote M. e. cicognanii should not be taken to indicate that the populations do not differ appreciably. Actually they differ in several characters although in no one of these is the degree of difference sufficient to allow of using it alone as a certain means of diagnosis. In invicta, as compared with cicognanii, the light-colored underparts are wider in relation to the dark-colored upper parts and the tail is longer by 4 per cent relative to the head and body. Given a population of each of the two subspecies, in which the skull is of the same mass, the hind feet are longer in invicta, there is more sexual dimorphism in size, and the anterior part of the skull differs in some particulars as just described in the comparison of the skull of invicta with other forms. Nevertheless, each of these differences is of an average sort. Therefore, and because overall size is about the same in the two subspecies concerned, one or a few specimens from, say, central Idaho, can be distinguished from animals from western Pennsylvania only with difficulty, if at all. The close resemblance of skulls of invicta and cicognanii may be a function of their living at approximately the same latitudinal position in a climate that has marked seasonal variation. Intergradation with richardsonii is complete and gradual; in one sense invicta is but little more than a small richardsonii. Intergradation with fallenda is shown by several specimens. These two races differ in large degree in color, and in size and shape of the skull of females. Although the geographic area where intergradation in color occurs is fairly wide, the area in which intergradation in cranial characters in females occurs, appears, from the inadequate material available, to be much narrower. Intergradation occurs freely in Washington with streatori but with muricus so far as known only in the Bitterroot and nearby mountains of northwestern Montana. The Snake River Plains and low country along much of the Columbia River appears to be uninhabited by weasels of the species erminea and hence there is opportunity for intergradation only in the mentioned area of Montana.
Mustela erminea alascensis (Merriam)Ermine
From richardsonii, alascensis differs in that the skull of the male averages smaller in every measurement taken and is 28 per cent lighter. Relative to the basilar length, the orbitonasal length is more and the braincase is shallower as measured at the anterior end of the basioccipital. The four adult females seen of alascensis are more variable than those of richardsonii and average smaller in some measurements and larger in others but give no proof of any consistent difference. From haidarum, alascensis differs in that the rostrum and entire preorbital part of the skull is actually as well as relatively much smaller in both sexes. In males of alascensis the length of the skull, and other cranial measurements of length, is more. In males, the mastoid breadth and zygomatic breadth are about the same as in haidarum, as also is the weight. M1 is larger but m1 and P4 are smaller. In females the anteroposterior extent of the inner moiety of M1 and length of tympanic bulla are about the same in the two subspecies but all other cranial and dental measurements in alascensis are less. It is 29 per cent lighter. The difference in the preorbital region is of about the same degree as in the males. Comparisons of the skull with those of arctica, salva, initis, celenda, and seclusa are made in the accounts of those subspecies. Remarks.—The relatively few specimens known of this race seem always to have been referred to in the literature by the name alascensis and the nomenclatural history is therefore simple. The original materials were obtained by the collector Clark P. Streator and the additional series of skeletons, one with skin, from Windham were procured by Stanton Price, a resident there. The subspecies is well differentiated from both arctica and richardsonii. Although actual intergrades are lacking between alascensis and the two races just mentioned I have no doubt that intergradation occurs with richardsonii and think it probably does also with arctica. The assignment of the three females from Mitkof Island, Zarembo Island, and Loring on Revillagigedo Island, is tentative because each is so young as not to show diagnostic cranial characters. The two other specimens from Revillagigedo Island (Carroll Inlet), labeled as males, are in white winter pelage. Only one, no. 136358, a subadult, is accompanied by a skull. The small size of each specimen, and its cranial characters which are intermediate between those of males and females of alascensis of the adjacent mainland, indicate the existence of a distinct race of weasel on Revillagigedo Island. On the chance that the one specimen with a skull is a dwarf, or is wrongly sexed as seems improbable, the population is tentatively referred to alascensis. Fig. 26. Map showing known occurrences and probable geographic ranges of the subspecies of Mustela erminea in southeastern Alaska.
Mustela erminea salva HallErmine
From alascensis, salva differs in that males have the preorbital region slightly wider in relation to the length of the tympanic bulla; also the braincase is smaller, actually as well as in comparison with the preorbital part of the skull. The tympanic bullae do not project so far below the squamosals and the braincase itself is shallower, in adults averaging only 11.5 mm. as against 12.5 mm. The overall depth of the braincase, including the tympanic bullae, when divided into the orbitonasal length gives an average of 93 (90-97) per cent whereas in alascensis the figure is only 85 (78-88) per cent. On this basis alone, everyone of the adult skulls of the two races can be distinguished. The females and subadult males show the same tendency to reduction in depth of braincase but not every individual among them can be surely distinguished. By weight the skull of salva of corresponding sex is only about 6 per cent smaller. Comparisons with initis and celenda are made in the accounts of those subspecies. Remarks.—Most of the specimens seen were collected by Allen E. Hasselborg, resident on Admiralty Island. On the basis of skulls—few skins, and measurements taken in the flesh, are available—salva more closely resembles alascensis than does any other subspecies so far known from southeastern Alaska. The race on Admiralty Island is only slightly differentiated from alascensis of the adjacent mainland.
Mustela erminea initis HallErmine
From salva, initis differs in that skulls of males average larger in every measurement taken, being 41 per cent heavier. Relative to the basilar length, the interorbital and preorbital parts of the skull are larger; the relatively greater interorbital and mastoid breadths are particularly noticeable. Although the depth of the braincase, including the tympanic bullae, is both relatively as well as actually more than in salva, the depth is relatively less than in alascensis which otherwise differs from initis in about the same way that salva differs from initis. Whereas the interorbital breadth in initis is about equal to the distance between the glenoid fossa and the posterior border of the external auditory meatus, the interorbital breadth is uniformly less than this distance in both salva and alascensis. In comparison with seclusa the teeth are of the same size but all measurements of the skull are larger. The skull of initis is 25 per cent heavier. In relation to the basilar length, the interorbital and preorbital parts of the skull are much less in initis. The preorbital and interorbital regions in initis are relatively smaller in comparison also with arctica. The one measurement of interorbital breadth in initis is greater in relation to the basilar length than in kadiacensis but the rostral region, and all that part of the skull anterior to the braincase, is relatively smaller in initis. Remarks.—The two adult males, nos. 286 and 289 from Saook Bay, provide convincing evidence of the existence of a distinct race of weasel on Baranof Island. Three other young specimens, almost subadult, from the same place are labeled as males although the basilar lengths of these skulls are only 35.5, 35.9 and 37.3 millimeters as against 39.6 and 40.5 in the two adult males. The difference in size is too great to be age-variation. The fact that 3 are definitely of one category and 2 of the other makes it doubtful that individual variation accounts for the differences. The small size of these 3 specimens and the fact that in each the anterior margin of the tympanic bulla is flush with the squamosal rather than protruded from the braincase, suggests that the three are females. If they are females, the amount of secondary sexual variation is rather less than would be expected by analogy with the amount obtaining in alascensis on the mainland and in salva on Admiralty Island. Another possibility that I can not disprove is that two stocks of weasels persist on Baranof Island, the two larger specimens being descendants of the stock which first became established on the island and the three smaller specimens being descendants of an individual ermine, or of ermines, that were rafted or otherwise transported to the island at a considerably later date. Assuming for the moment that there are two stocks, it must be admitted that each one differs from any stock known from elsewhere. Therefore, each stock would be presumed to have been long resident on the island. But—two stocks as closely related as the two in question would not be expected to persist for long in an area as small as that of Baranof Island because competition would give one the ascendancy. Therefore, the first suggestion, namely that the three smaller animals are really females, seems the more probable. The feasible way to clear up the present uncertainty is, of course, to obtain additional specimens, carefully labeled as to sex. Yet another reason why additional collecting is desirable in this area is to ascertain whether there is subspecific differentiation between the ermines of Baranof and Chichagof islands. The one specimen available from the latter island, although in general like the three smaller animals from Baranof Island, differs in the fuller (less scooped out) medial side of the tympanic bulla and to a slight degree in each of some other features. This specimen from Chichagof Island is labeled as a male also.
Mustela erminea celenda HallErmine
Differences from richardsonii are indicated in the formal description just given. Additional to differences therein noted, celenda differs from initis in larger interorbital and preorbital parts of the skull although dimensions of other parts of the skull and the teeth are about the same or even less. From salva, celenda differs in larger average size in every measurement taken, except for the inner moiety of M1 which is about the same. The skull of celenda is 35 per cent heavier. In relation to the basilar length the skull of celenda is wider, especially in the interorbital and preorbital regions. In comparison with alascensis the tympanic bullae are of approximately the same length; otherwise essentially the same differences obtain as are noted in comparison with salva and the zygomatic breadth is relatively more in celenda. From seclusa, in which the teeth are of comparable size, celenda differs in that every cranial measurement is more and the skull is 28 per cent heavier. Because the skull of celenda is so much longer, its dimensions in other planes are less in relation to the length than in seclusa. M. e. celenda is larger in every part measured than haidarum, 21 per cent heavier, and in relation to the basilar length the interorbital, and preorbital, parts of the skull are smaller, the braincase is shallower, and the skull is relatively wider across the zygomata and mastoid processes. In comparison with kadiacensis, differences are: 26 per cent lighter, skull shorter; in relation to the basilar length, braincase shallower as measured at the anterior end of the basioccipital, tooth-rows shorter but orbitonasal length more. In comparison with arctica all parts measured of the teeth and skull of celenda are smaller and its skull is 34 per cent lighter. In relation to the basilar length, the interorbital breadth of celenda is only slightly less but its skull is narrower across the rostrum and zygomata, the tooth-rows are shorter, and the braincase is shallower. Remarks.—The late George Willett in the course of his work in Alaska collected most of the known specimens of this strongly differentiated subspecies. In both coloration and cranial characters the distinguishing features are so well marked that the zoÖlogist could with reason accord full specific rank to celenda. Nevertheless it obviously is an ermine. Also, races from other islands of southeastern Alaska tend to bridge the gap, as regards cranial features, between celenda and the mainland ermine. The specimen from Dall Island agrees in all respects with topotypes. The specimen from Howkan on Long Island is in white winter pelage and the skull has suffered shrinkage from some chemical solution; the reference of this specimen to celenda is tentative.
Mustela erminea seclusa HallErmine
From alascensis and salva, seclusa differs in larger teeth, shorter skull, much larger preorbital and interorbital regions, actually as well as in relation to basilar length. Excepting the teeth, which are of about the same size, the same general differences obtain in comparison with initis which, however, is 29 per cent heavier. From celenda, seclusa differs in smaller skull in all parts measured, being 22 per cent lighter. The teeth are about the same size. In relation to its length the skull of seclusa is much broader and deeper. From haidarum, seclusa differs in: teeth larger; skull shorter and more convex in dorsal outline along median longitudinal axis; in relation to basilar length, skull broader, deeper and braincase relatively shorter. Remarks.—The characters shown in the one available skull are far outside the limits of individual variation for other known subspecies. Other specimens are much to be desired to ascertain what the "average" individual is like and to learn the characters of the female.
Mustela erminea haidarum (Preble)Ermine
From richardsonii, haidarum differs in that skull of the male is actually larger in its anterior part (breadth of rostrum, interorbital breadth and orbitonasal length) but all measurements of other parts average less. In relation to the basilar length, the tympanic bulla is shorter but all other measurements are more. In the skull of the female, which is 23 per cent heavier, the width of the tympanic bulla and anteroposterior extent of the inner lobe of M1 are the same; in all other measurements the female of haidarum is larger, and in relation to the basilar length all measurements are more except the depth of the skull at the anterior margin of the basioccipital and the width of the tympanic bulla, which are less. By actual weight the skull of the male is 25 per cent lighter and the skull of the female 24 per cent heavier than in richardsonii. From fallenda and anguinae, haidarum differs in that measurements of the skulls of both sexes either average more, or are uniformly more, with two exceptions. These are the lesser length and breadth of the tympanic bulla, in comparison with males of fallenda, and the dimensions of M1 which are about the same in all three races concerned. The pre- and interorbital parts are larger in relation to the remainder of the skull. The postorbital breadth is actually a third more than in fallenda. In relation to the basilar length, the tympanic bulla is shorter and the braincase deeper than in males of anguinae. The skull of the male is 27 per cent heavier than that of fallenda and 58 per cent heavier than that of anguinae. The skull of the female is 59 and 50 per cent heavier than those of fallenda and anguinae, respectively. Comparison of the skull with those of alascensis, celenda and seclusa has been made in the accounts of those subspecies. Remarks.—The available specimens of this ermine were obtained by J. H. Keen in 1898, Wilfred H. Osgood and E. A. Lewis in 1900, W. W. Brown in 1914, J. A. Munro in 1917 and 1918, and Allan Brooks in 1920. M. e. haidarum has more claim to full specific status than any other race of ermine because the diagnostic structural features are numerous and individually of relatively great degree. Indeed, individual variation appears not to bridge the gap between any population of haidarum and other subspecies and strong reasons could be advanced for according haidarum the status of a full species. It differs from the subspecies of erminea on the adjoining mainland and adjoining islands to the north and south and agrees with the Arctic races (arctica, polaris, semplei and kadiacensis) in great extent of the color of the underparts, extension of this color onto the underneath side of the tail, long black tip of the tail and general form of the skull including the relatively heavy preorbital region. The color although darker than in the Arctic subspecies, is lighter than in the insular races immediately to the north and south. In combination, the features mentioned could be taken as indication that haidarum is a relict population from a former glacial period. Assuming that it is a relict population, the color may have become slightly darker since that period but the main response appears to have been a decrease in size for this is a much smaller animal than the Arctic ermines. The size is about what would be expected if one were to judge by the slightly larger ermines on the islands of southeastern Alaska to the north and the smaller ermine on Vancouver Island to the south. The ermines of the islands of southeastern Alaska, excepting possibly the incompletely known seclusa, have fewer characters of the Arctic races and more characters of the races of the adjoining mainland. Therefore, a possible inference is that the distinctive characters of ermines of the Alaskan islands developed with the aid of isolation from stocks which reached the islands after the glacial period. M. e. haidarum may have found its way to the Queen Charlotte Islands in the glacial period.
Mustela erminea anguinae HallErmine
The sexual dimorphism in the skull is slight, the skull of the male being only a third heavier than that of the female. In fallenda of the adjacent mainland to the east the male is three-fourths heavier than the female. In comparison with fallenda, males are smaller, averaging less in every cranial and dental measurement taken and by weight are a fifth lighter; sagittal crest absent rather than present; tympanic bullae flush with squamosal rather than projecting below floor of braincase; in relation to basilar length, tympanic bullae smaller, braincase deeper and broader, skull wider interorbitally and across zygomata. Females are larger than in fallenda, and with one exception average larger in every cranial and dental measurement taken, being 6 per cent heavier. The one exception mentioned is the lesser actual length of the tympanic bulla in anguinae, in which the length of the tooth-rows is about the same as, rather than less than, the length of the tympanic bulla. The postorbital breadth is greater than in fallenda and the anterior edges of the tympanic bullae are flush with the squamosals rather than projecting below the floor of braincase. In relation to the skull as a whole the preorbital and interorbital parts are larger. In comparison with streatori, skulls of males are of about the same size, anguinae being only 9 per cent heavier. The length of the tooth-rows is ordinarily less than, rather than about equal to, the length of the tympanic bulla; sagittal crest wanting rather than present since in anguinae the temporal muscles meet usually only at the posterior end of the braincase instead of all along the midline on its top; tympanic bullae narrower and more nearly flush with squamosal (less protruded from braincase). Relative to the basilar length, the zygomatic breadth is more, the tympanic bullae are narrower, and the braincase is deeper at the anterior end of the basioccipital. The female is 41 per cent heavier than streatori, there being no overlap in most cranial and dental measurements. M1, however, is approximately the same size in each subspecies. The tooth-rows and tympanic bulla are of almost equal length whereas in streatori the length of the tooth-rows is less than that of the bulla. Differences from olympica, in males, are: M1 shorter; all other measurements of teeth and parts of skull averaging larger; skull 20 per cent heavier; tooth-rows averaging shorter than tympanic bulla rather than about the same; relative to basilar length, braincase deeper at anterior end of basioccipital and tooth-rows shorter. The skull of the female is 64 per cent heavier, larger in every measurement taken without overlap; temporal ridges meeting, rather than separated, at lambdoidal crest; length of tooth-rows about equal to, rather than shorter than, tympanic bulla; in relation to basilar length, skull deeper, orbitonasal length more, mastoid and zygomatic breadths more, and tympanic bullae shorter. Remarks.—References in the literature to this insular race mostly were under the name streatori until 1932 when in the course of the present study the name anguinae was proposed. A few specimens have been taken by nearly every student of small mammals who has collected on Vancouver Island. Arthur Peake and Herbert Laing have probably collected more specimens than any other two zoÖlogists. M. c. anguinae is noteworthy for the slight secondary sexual variation in size; the disparity between the two sexes is less than in any other American subspecies of erminea. By linear measurement the body of the female is only 7 per cent shorter than in the male (178 versus 191 mm.). Linear measurements and weights of the skulls of the two sexes are further indicative of this approximation in size. By weight the skull of the female is only a fourth lighter than that of the male, or, stated in another way, the male's skull is only a third heavier (1.2 versus 0.9 grams). No geographic variation has been detected between lots of specimens from different parts of Vancouver Island. The one specimen available from Salt Spring Island presents no obvious differences from selected individuals from Vancouver Island. The winter pelage is more often brown than white. Of 17 specimens seen in winter pelage or in transition pelage, only 6 are white. These 6 are from Comox, Stamp River, Hilliers, Jeune Landing and Port Alice. Of the 34 specimens in brown pelage, 7 have the dark color of the upper parts meeting on the abdomen. Six of the 34 have brown color on the pectoral region. In two, this is a separate patch but in the other four the dark color is a continuation of the upper parts and extends in front of each foreleg over part of the pectoral region, but the two extensions, one from either side, do not meet on the underparts. The color of the lips was recorded in 22 individuals: one had both the upper and lower-lips white; 7 had the upper lips brown and the lower lips white; in 14 both the upper and lower-lips were brown.
Mustela erminea fallenda HallErmine
Fig. 27. Map showing known occurrences and probable geographic ranges of the subspecies of Mustela erminea in Washington and parts of British Columbia and Oregon.
In comparison with richardsonii, skulls of males differ as follows: averaging smaller in every measurement taken with no overlap in several dimensions; 40 per cent lighter; in relation to basilar length, rostrum (orbitonasal length) longer and skull slightly broader interorbitally. Females average smaller in every cranial and dental measurement taken with no overlap in basilar length, length of tooth-rows and length of tympanic bulla; 22 per cent lighter; breadth of rostrum more, rather than less, than 30 per cent of basilar length; in relation to basilar length, pre- and interorbital parts of skull larger, and mastoid breadth more. Differences from males of olympica are: size larger with no overlap in most measurements; 50 per cent heavier; tympanic bullae longer than upper tooth-rows rather than of about equal length; in relation to basilar length, rostrum shorter, braincase wider and deeper, zygomata more expanded. Females are larger with no overlap in most measurements; 35 per cent heavier; in relation to basilar length, pre- and interorbital regions narrower, braincase deeper and wider across mastoids. Differences from streatori, in males, are: skull averaging larger in every cranial and dental measurement taken; 36 per cent heavier; tympanic bulla longer than, instead of about same length as, upper tooth-rows. In females the inner lobe of M1 is shorter anteroposteriorly; otherwise all measurements of fallenda average larger and it is 33 per cent heavier; rostrum and interorbital region broader in relation to remainder of skull. In comparison with gulosa, skulls of males differ as follows: averaging larger in every measurement taken with no overlap in several dimensions; 50 per cent heavier; tympanic bullae with anterior margins projecting slightly below squamosals rather than flush with same; length of bulla more than, rather than about same as, that of upper tooth-rows. Considering the great difference in size, the relative proportions are remarkably alike. In females, length of inner lobe of M1 about the same; otherwise averaging larger in every measurement taken; 44 per cent lighter; relative to basilar length, tooth-rows longer, skull wider across zygomata and mastoids, rostrum and interorbital regions slightly narrower, skull shallower in plane of last upper molars. Comparisons with haidarum, invicta and anguinae are made in accounts of those subspecies. Remarks.—Until the name fallenda was proposed in the course of the present study, most of the specimens of this race were assigned to streatori. Intergradation with streatori is complete as it is also with invicta and richardsonii, in other words with each of the subspecies whose ranges meet that of fallenda. In color and in size the difference is least between streatori and fallenda. As between fallenda and invicta the size is not greatly different and the intergradation in color is gradual. Between fallenda and richardsonii intergradation is somewhat different and to fully appreciate its nature we should remember that the color of fallenda resembles that of the saturate coastal races, streatori, anguinae and olympica although the black tip of the tail is longer. In this latter feature and in several cranial details, as well as in greater degree of secondary sexual variation in size, fallenda resembles richardsonii. Because the two differ more than do most subspecies of ermine whose ranges meet, some of the intergrades at first inspection appear to be widely different from either parent stock. For example, specimens from Alta Lake, British Columbia, may give this impression because the combination of large size and dark color suggests a kind of ermine different from either fallenda or richardsonii. In no instance, however, has there been found in these intergrades any character other than those occurring in one or the other of the two parent races. Along the coast in the north part of the geographic range assigned to fallenda, some specimens nearly typical of richardsonii have been taken so near to the place where fairly typical fallenda was obtained that I have doubted whether there is intergradation in the usual fashion in this area; more specimens will have to be obtained from this coastal area to resolve the doubt one way or the other. The winter pelage is brown in all specimens at most localities. The only white pelage seen was in each of three specimens from Glacier, Whatcom County, Washington. A fourth specimen from there is in brown winter pelage. At any one locality there is much variation in the degree to which the dark color of the upper parts encroaches on the area that in most other races is light-colored. An extreme degree of encroachment is shown by a specimen taken on December 1, 1935, by R. A. Cummings, at Vancouver, British Columbia, in which the light color occurs only in three restricted areas, the chin, the throat and the lower breast; otherwise the coat is brown. There are other specimens, for instance from the type locality, which differ mainly in having an additional white spot in the inguinal region. The opposite extreme, in a specimen also from the type locality, is where the least width of the light-colored underparts on the abdominal region is a third of the circumference of the body. The two extremes are connected by a dozen intermediate stages. Of 64 specimens in which the color of the lips was carefully examined, one, from Vancouver, has both the upper and lower-lips brown; 9 have both the upper and lower-lips white; and 54 have the upper lips brown and the lower lips white.
Mustela erminea olympica HallErmine
In comparison with streatori, skulls of corresponding sex average smaller in every measurement taken with no overlap in most of those of females. Exception is to be made for the inner lobe of M1 in males where the size is the same. By weight males are smaller by 10 per cent and females by 14 per cent. In relation to other parts of the skull the tympanic bullae are narrower and in females they are shorter as well. Comparison with anguinae and fallenda has been made in the accounts of those subspecies. Remarks.—The smaller size, especially of females, is the principal feature distinguishing this race from streatori. On the basis of available data the female of olympica is smaller than that of any other race and hence is the smallest adult weasel of the species erminea, in either the Old World or in America. Intergradation with streatori is indicated by specimens from the southern end of Puget Sound. These specimens are intermediate in size between typical examples of the two races concerned. The color of the upper parts is uniform and the color pattern varies less than in geographically adjoining races. The white color of the underparts is restricted to a thin line on the abdominal region, but widens out posteriorly in the inguinal region and anteriorly over the pectoral region, throat, chin and lower lips. The upper lips are brown. The brown of the upper parts extends around in front of each foreleg, the two brown areas not quite meeting on the lower throat. The above description applies to each of the 19 specimens examined with regard to these details. Every specimen seen in the winter coat was brown, not white.
Mustela erminea streatori (Merriam)Ermine
Comparison with anguinae, fallenda, olympica, gulosa and muricus is made in accounts of those subspecies. Remarks.—This weasel is rare in collections and the best material of it was obtained by Alex Walker in Tillamook County, Oregon, where he resides. The almost ideal series of 30 specimens showed the range of secondary sexual, age, and individual variation expectable in the small ermines of the Pacific Coast of the United States and was the means of allowing satisfactory decision on questions of classification in the related subspecies in which individuals are of comparable size. Intergradation with each of the geographically adjoining subspecies, olympica, fallenda, invicta, gulosa and muricus is shown by specimens examined. With the last mentioned subspecies, intergradation is shown by two specimens from as far south as Siskiyou County, California, assigned to muricus. The application of the name streatori is difficult because it was based on a specimen from a place where two clines cross. The north-south cline is one of size which decreases to the south. The east-west cline is one of intensity of color, the westernmost (coastal) population being the most intensely colored. The type locality of streatori is at the place where two lines perpendicular to one another, and representing the two clines, cross. This intersection is near the place where the ranges of several subspecies meet. The nomenclatural question is, to which one of 6 subspecies should the name streatori apply. Specimens from barely within the geographic boundaries of four of these subspecies so closely resemble topotypes of streatori that a student with material at his disposal from only the area about Puget Sound naturally would apply the name streatori to all of his specimens, and knowing even of the arrangement adopted in the present account the student will have difficulty in identifying his specimens according to it. Not only will the student find the arrangement difficult, but probably unsatisfactory if he thinks of streatori as being the kind of animal represented by topotypes. I conceive of topotypes of streatori as being nontypical of the subspecies; they are intergrades with fallenda. My aim was initially to work out the geographic ranges of subspecies and only subsequently to apply names, according to which type localities fell within the previously determined geographic ranges. By this procedure no greater weight was given to a holotype and to topotypes than to specimens from any other locality. Of the 40 specimens seen in winter pelage, only one is white. It is from Darrington in the Cascade Mountains of Washington. The 39 others are brown and I doubt that the white pelage ever occurs in the low coastal territory included within the geographic range of streatori. This subspecies resembles anguinae and olympica in the great extension of area of the dark-colored upper parts at the expense of the area of the light-colored underparts. The usual arrangement is one where the brown of the two sides nearly meets on the midventral line leaving a sizable, inguinal area of light color connected by a thin line to the sizable area of light color on the pectoral region. The light color of the pectoral area ordinarily is continuous with the light-colored area of the throat and chin but the dark color of the upper parts extends around in front of each foreleg. These extensions of dark color meet on the chest in only 2 of the 56 specimens examined in this regard. Across the abdomen the dark color is continuous in 4 of the 56 specimens. The lower lips are brown instead of white in only 3 individuals and in 2 of these the lip of one side is brown and its opposite is white. The variation in color-pattern is less than in anguinae or than in fallenda.
Mustela erminea gulosa HallErmine
In comparison with streatori, skulls of males and females average smaller in every cranial measurement taken. Teeth of about same size and males 9 per cent, and females 8 per cent, lighter. In relation to basilar length, skull of female shallower, tympanic bullae slightly shorter and, on the average, zygomata less expanded. In comparison with muricus, males average larger in every measurement taken; 23 per cent heavier; in relation to other dimensions, braincase shallower at anterior end of basioccipital. Females are of about equal size; in relation to other dimensions, braincase shallower and mastoid and zygomatic breadths less. Comparisons with invicta and fallenda have been made in the accounts of those subspecies. Remarks.—This is not a strongly marked race and in most of the characters used for differentiating it from other races it resembles either streatori to the west or muricus to the southeast. Nevertheless, there is a geographic area, the southern Cascades of Washington, throughout which individual characters are combined in essentially the same way and there are a few features, for instance, smaller skull of the female, in which gulosa differs from either of its close relatives. In view of these circumstances and because the animals can not well be included in the subspecies streatori or muricus, gulosa is recognized as distinct. The races gulosa and olympica are what might be termed weakly differentiated subspecies in contrast to the strongly differentiated subspecies streatori and muricus. Of the 21 specimens in winter pelage, 17 are white and four are brown. The brown winter coat is distinctly paler, with more of a smoky tinge, than the brown summer pelage. The light-colored underparts are narrower than in the subspecies immediately to the east but are wider than in the coastal forms to the west. The dark color of the upper parts extends onto the chest in front of the forelegs, as in the coastal forms, in only one of the 13 specimens in summer pelage and in it on one side only. The black tip of the tail is short as in the coastal forms. One specimen is in transitional pelage. It has acquired approximately half of the white winter pelage and was taken on October 12, 1897, at Keechelus Lake.
Mustela erminea muricus (Bangs)Ermine Plates 7, 8, 12, 13, 14 and 41
In comparison with streatori, males average smaller in every measurement taken with no overlap in most dimensions; 25 per cent lighter; anterior margin of tympanic bulla more nearly flush with squamosal, that is to say less protruded from braincase; in relation to other dimensions of skull, braincase shallower anteriorly (at plane of last molars) and deeper posteriorly (at anterior end of basioccipital). Females average smaller in every measurement taken except mastoid and zygomatic breadths which are actually more; 6 per cent lighter; in relation to other parts of skull, preorbital and interorbital parts slightly smaller; in relation to length of skull, braincase shallower. Comparison with invicta and gulosa is made in the accounts of those subspecies. Remarks.—The smallest males of the entire species are of this subspecies and the females of it are barely larger than those of olympica and gulosa and hence are among the three smallest. The material now available consists only of one or a few specimens from each of several widely separated localities. If as many specimens per unit area were available as there are of the species M. erminea from southern British Columbia, geographic variation warranting the division of muricus into more than one subspecies might be revealed. Evidence pointing in this direction is comprised in the pale color and small size of the pair of adults from Wheeler Peak on the eastern border of Nevada; the suggestion is that there is a distinct pale race of small individuals in the isolated spots of boreal life-zone in the mountains of the desert. The color and size of the specimens from the Toyabe Mountains, and that from the Pine Forest Mountains, both places also in Nevada, nevertheless, lend no support to this suggestion. Comparison of specimens from the Rocky Mountains of Colorado with those from the Sierra Nevada of California gives no basis for recognizing more than one subspecies. Therefore, Putorius streatori leptus Merriam with type locality at Silverton, San Juan County, Colorado, falls as a synonym of the earlier named Putorius (Arctogale) muricus Bangs with type locality at Echo, El Dorado County, California. Furthermore, specimens from northern New Mexico, the southernmost known area of occurrence for the subspecies (and for the species), are as large as specimens from far north in the range of the subspecies, say, in northwestern Wyoming; there is therefore no evidence of progressive decrease in size to the southward as in advance of study I supposed existed in muricus. This erroneous supposition was held because I knew that there was a decrease in size to the southward in the species as a whole and also in each of the subspecies richardsonii and invicta directly to the north of muricus. Intergradation with invicta is shown by specimens from southwestern Montana. Where the margins of the geographic ranges of invicta and muricus approach one another elsewhere, low-lying territory, zonally unsuited to the existence of the species, occurs along the Snake and Columbia rivers, and precludes any chance of intergradation except around the head of the Snake River Plains. Two specimens, here referred to muricus, from Siskiyou County, California, in both color and cranial characters, are intergrades with streatori and might be referred with almost equal propriety to streatori.
Mustela erminea? angustidens (Brown)
Remarks.—The ten specimens studied by the writer fall into two groups of six larger individuals and four smaller. Upon comparing these with each sex of the three species of American Recent weasels, frenata, erminea and rixosa, it is seen that size, and to some degree shape, rule out of consideration both sexes of rixosa and also males of frenata. Thus we are left with females of frenata and males and females of erminea. So far as size is concerned, it can be assumed that the larger specimens are females of frenata and that the smaller are males of erminea. This assumption has in its favor also, the fact that the postglenoidal length of the skull accords with that in Recent specimens. The difference in this regard in Recent animals is that the postglenoidal length of the skull, expressed as a percentage of the total (condylobasal) length of the skull, amounts to: In the fossils the percentage for the larger skulls is 46; for the smaller skulls it is 48. It may be that the ten fossil skulls are six female frenata and four male erminea but I think not. In the first place a skull of different shape, seemingly of the frenata stock, is known from the deposit and it is almost certain that two subspecies of the same species would not occur at the same place at the same time. It is possible, of course, that parts of the deposits were laid down at times so far apart that a shift in geographic range of two subspecies had occurred. This one skull, seemingly of the frenata stock, is the type of Putorius gracilis Brown (see p. 404) and was regarded as the only known specimen of gracilis. Regardless of the specific identity of this one specimen named gracilis, the chances of obtaining otherwise from a deposit, like that in Conard Fissure, six females of frenata and four males of erminea without a male frenata or a female of erminea coming to light are so slight as strongly to incline me to the view that the six larger specimens are males of the same species to which the 4 smaller specimens belong. By either this interpretation, or the one initially considered (of female frenata and male erminea), the animals from the fissure are at least subspecifically distinct from any American Recent weasel. Furthermore, by this latter interpretation each sex of this weasel, angustidens, is intermediate between the frenata and erminea stocks in the feature of postglenoidal length which feature, at any place where the two Recent species occur together, serves to distinguish one from the other. In the northernmost subspecies of erminea (arctica for example) the postglenoidal length in some males is no longer than in males of frenata. Considering general size, angustidens agrees better with erminea than with frenata and this circumstance has influenced me to place angustidens as a subspecies of erminea. Today, erminea is not known to occur nearer Conard Fissure than northern Iowa, more than 400 miles to the northward. In comparison with the race there, bangsi, males of angustidens are of approximately the same size but in the shorter distance between the glenoid fossa and anterior margin of the tympanic bulla, and also in the lesser postglenoidal length of the skull, angustidens resembles the northernmost American subspecies of erminea. Females of angustidens differ more from any living weasel than the males do. The females are much larger than those of bangsi, and among living American races of erminea most closely resemble intergrades between arctica and richardsonii which intergrades are found approximately 1700 miles to the north of Conard Fissure. In females, the preorbital part of the skull in M. e. arctica is broader and in M. e. richardsonii narrower than in angustidens. If it seems strange that females of angustidens resemble one subspecies whereas males, in size, resemble another subspecies almost a thousand miles distant, it should be remembered that the degree of sexual dimorphism varies much from one subspecies to another in the Recent animals. An example is furnished by Mustela erminea fallenda and Mustela erminea invicta. The assemblage of mammals from Conard Fissure includes several species of boreal predilections which, like Mustela erminea, now occur only much farther north than Arkansas. At one time the edge of the sheet of ice was only about 200 miles north of Arkansas. It may be significant that the cranial characters of the female ermine from the Fissure, and qualitative cranial characters of males from there, are most nearly approximated among Recent weasels by those which live along the southern edge of the frozen tundra. In view of what has been said, the possibility should be considered that the distinctive cranial features of angustidens may be the result of evolutionary change in time as well as of geographic variation resulting from horizontal placement. MUSTELA RIXOSA (Bangs)Least Weasel (Synonymy under subspecies)
Characters for ready recognition.—Differs from both Mustela erminea and Mustela frenata by tail a fourth or less of length of head and body and without a black tip (at most a few black hairs at extreme tip in rixosa), and from M. frenata and from M. erminea in regions where it and rixosa occur together, by basilar length of skull less than 32.5 in males and less than 31.0 in females. Characters of the species.—Size small: Total length less than 250 in males and 225 in females; tail a fourth or less of length of head and body, and without a black pencil and at most with a few black hairs at extreme tip; caudal vertebrae 11 to 16, normally 15 in M. r. rixosa, and 11 in one M. r. eskimo examined; skull with long braincase and short precranial portion, thus essentially same shape as in M. erminea but the largest males of M. rixosa always with a lesser basilar length that even the smallest females of M. erminea or M. frenata of the same geographic area. In fact no specimens of M. frenata have skulls so small as the largest M. rixosa, and skulls of equal size of M. erminea and M. rixosa, for example, M. erminea muricus of Colorado and M. rixosa eskimo of Alaska, differ in that when the skulls are viewed from directly above those of rixosa have the mastoid processes more prominent, or the braincase is higher in relation to its width or both differences together prevail. Stated in another way, comparison of skulls of equal size of rixosa and erminea shows that in the latter the braincase is more nearly flat and is wider above and in front of the mastoid processes; therefore, the greatest breadth of the braincase equals or exceeds the mastoid breadth, whereas the reverse is ordinarily true of rixosa. Geographic variation.—In the Old World four subspecies are currently recognized (see Allen, 1933:316) and the same number is here recognized in North America. Length of the tail, length of head and body and hind foot, breadth of the rostral part of the skull in relation to its length, and position on the side of the head of the line of demarcation between the dark color of the upper parts and the white underparts, are the features in which geographic variation has been detected. The general impression is that the amount of geographic variation is much less than in Mustela frenata and only slightly less than in Mustela erminea of the same geographic area. Nomenclature.—It is exceptional for a species which occurs in both the Old- and New-World to take its specific name from New World material, especially if the name was proposed as recently as 1896; most circumboreal species take their names from descriptions of European specimens. Although the least weasel, Mustela rixosa (Bangs) 1896, seems now to be an exception, it may yet turn out that the first available name was based on European material. Zimmermann (1943) shows that the least weasel actually was named on the basis of European material long before 1896 and concludes that the name Putorius minutus Pomel, 1853, based on a specimen from France, is the first available name. Because Putorius nowadays is relegated to subgeneric rank under the generic name Mustela, we have for consideration the name-combination Mustela minuta (Pomel). Unfortunately for Zimmermann's conclusion, Mustela minuta Pomel is not available because it is preoccupied by Mustela minuta Gervais [= Palaeogale minuta (Gervais), 1848-1852—see Simpson, 1946: 2, 12], a name applied to another species of small mustelid from the Oligocene or lower Miocene deposits of Europe. Some other early names thought by Zimmermann (1943:290) to have been based on the dwarf weasel of Europe are judged to be nomina nuda and therefore are to be ignored. The name Mustela minor Nilsson 1820 was thought by Miller (1912:402) to be a renaming, and hence a synonym, of Mustela nivalis Linnaeus. If that is the case the name does not apply to the dwarf weasel. If the name Mustela minor Nilsson was instead based on the dwarf weasel, the name might still be unavailable, depending on rulings on secondary homonyms, because the name might be preoccupied by [Lutra] minor Erxleben 1777 which is a synonym of [Mustela] lutreola Linnaeus 1766. Two names seemingly available for weasels, and in use for them today, which might replace rixosa as the name of the species, are, first, Mustela boccamela Bechstein, 1801, of Sardinia [= Mustela nivalis boccamela of Miller, 1912, 405] and second, Putorius numidicus Pucheran, 1855, of Morocco and Algeria [= Mustela numidica of Allen, G. M., 1939, 183]. As they stand in the current literature, Mustela numidica is a species distinct from the dwarf weasel and the other name, Mustela nivalis boccamela, is an insular subspecies of the mouse weasel. Zimmermann (1943:292), however, implies that M. numidica may belong to the dwarf weasel group when he says "Ob auch iberica Barr.-Ham. als Unterart zu minuta Pom. zu stellen ist, soll hier nicht untersucht werden, ebensowenig die von Cabrera vermutete ZugehÖrigkeit der grossen nordafrikanischen M. numidica Puch. zur 'iberica-Gruppe'." The answer to this problem requires a taxonomic, rather than a nomenclatural, decision. Whether either M. numidica or M. boccamela are conspecific with the dwarf weasel I cannot at this time ascertain for want of adequate specimens. Because these two names, M. boccamela, and M. numidica, are assigned to kinds of weasels which are currently regarded as specifically distinct from the dwarf weasel, and because all the other names which certainly have been assigned to Old World populations of the dwarf weasel before 1896, so far as I know, are nomina nuda or are preoccupied, the next available name, Mustela rixosa (Bangs, 1896), is here employed. Remarks.—This species may have a wider geographic range in northeastern North America than is now known. Strong (1930:7) writes that the Naskapi Indians of the interior country of Labrador between Hamilton Inlet and Ungava Bay "have only one name for weasel, mÉ-tah-kwut, but they say there are three kinds in their territory, a large, an intermediate, and a very small weasel. The latter suggests the least weasel ... which has not been recorded from northern Labrador." In the northern part of the range of the species, the winter pelage is white and the summer pelage is brown. In the southern part of the range, that is in the range of the subspecies allegheniensis, the winter pelage is either brown or white and the time of the molt into winter pelage is irregular; each of eleven individuals from Pennsylvania, Michigan and Ohio, taken in December, January, February and March is mostly white but retains some considerable part of the brown pelage of the previous coat on top of the head and usually also along the midline of the entire dorsum. These eleven animals include individuals of each sex. Of each sex, some are adults and some are subadults. Therefore, the delayed or incomplete fall molt, at present, cannot be correlated with either sex or with any particular age. No wild-taken specimens of M. erminea or of M. frenata of the same region show this delayed or incomplete molt. Possibly this delay or incompleteness of molt is the result of the same cause that lies behind the birth of some M. rixosa in midwinter. As listed below, several litters of young have been found in midwinter. In fact it appears that in the United States, young may be born in every month of the year although, according to existing information, more litters are produced in spring and in winter than in summer and autumn. Many juveniles and young of allegheniensis examined in study collections clearly were born in spring but about as many seem to have been born in midwinter as at any other time (in the light of present knowledge) and this is in contrast to what we know of the two other species of American weasels since their young, so far as known, are born in spring. One instance is worthy of detailed comment. An adult female, no. 783 Ohio State Museum, taken on January 31, 1931, at Vinton, Meigs County, Ohio, bears the following notation on the attached label "nest plowed out of ground. Very small young escaped—marked like parent. ? was nursing." The enlarged mammae on the dried skin substantiate the statement that the female was nursing young. She has a brown mask continuous from one ear through the eye, across the forehead and through the other eye to the opposite ear. On each side of the body a stripe of brown 5 to 10 mm. wide extends from the upper part of the foreleg back to the thigh and base of the tail, uniting there with its opposite and covering the tail. There are a few spots of brown on the shoulders, and rump and one on the middle of the back. Otherwise the specimen is white. One implication of the statement on the label that the young which escaped were marked like the parent (presumably this female parent) is that this female is a partial albino. I am more inclined, however, to the view that there was an unseasonable activity of the particular glands of internal secretion the hormones of which promote embryonic growth and that these glands, or others controlled by them, were in some way responsible for an abnormal progress of molt, or for a reversal of molt in that one molt began before the previous molt had been completed. Excepting this one specimen, no. 783 from Vinton, Ohio, all of those in transitional pelage indicate that the direction of the molt pattern is the same as in M. frenata and M. erminea. That is to say, the autumnal molt begins on the midventral line and the molt in spring begins on the mid-dorsal line. Furthermore, the normal progress of each molt appears to follow the same pattern that has been described above for Mustela frenata. A possible explanation of unseasonal molt in the southeastern area of occurrence of the species Mustela rixosa, and a possible explanation of the abnormal molt of the female from Vinton, Ohio, is that the species has only relatively recently invaded the area, and has had insufficient time to adjust the physiology of its molting mechanism to the longer periods of daylight that obtain later in autumn and earlier in spring than farther north. In the other two species of American weasels, the change in length of periods of light, it will be recalled, is known to indirectly control both molt and some changes in the sexual cycle. Wright (1942B:109) has shown that molt in spring precedes by one or two months the birth of young in M. frenata, that the two phenomena are correlated in a way that is statistically significant, and recognizes that progressively longer periods of daylight may be the causal stimulus. The suggestion made above that M. rixosa does not live in New England or in the Rocky Mountains of the western United States because each of the two areas already is inhabited by weasels of almost equally small size, is in line with the idea that rixosa is a recent immigrant to America, or more precisely that rixosa arrived later than erminea. Natural History.—Habitat and Numbers.—Soper (1946:136) recounts that near the junction of the Antler and Souris rivers, Manitoba, this species occurs "both in the river valleys and on the upper prairies," and later (1948:55), with reference to the Grand Prairie of the Peace River region of Alberta, writes that the least weasel "inhabits both parklands and mixed wood forest environments." At most times, wherever found, the least weasel is regarded as rare. Not only mammalogists regard it as rare and as a desirable catch, but Indians likewise value it, probably because of its rarity. For example, Osgood (1901:69-70), who caught a female least weasel at Tyonek, Alaska, writes that: "The natives regard the capture of one of these rare animals as a piece of great good fortune. One old Indian who frequently visited our cabin told us that his brother who had caught one when a small boy had in consequence become a 'big chief'; and he assured me that since I had caught one I must surely be destined to become a man of great wealth and power." Swenk's (1926:313-330) account of the species in Clay County, Nebraska, shows, however, that the animal was far more abundant in 1916 and 1917 than subsequently and inferentially than it was before 1916. Clearest proof of multiannual fluctuation is provided by P. O. Fryklund's (Swanson and Fryklund, 1935:120-126) receipt of weasels from Roseau County, Minnesota. From 1895 to 1932 he had approximately equal opportunity to receive least weasels each year. Those which came to his attention were distributed by years as follows: 1895-1927, 7 individuals in all; winter of 1927-28, 3 individuals; winter of 1928-29, 59 individuals; 1929-1930, 84 individuals; 1930-1935, 3 individuals. "These records indicate a very definite increase in the abundance of least weasels in the Roseau region [in] the two years from the autumn of 1928 to the spring of 1930. Mr. Fryklund has handled 166 least weasels in his 40 years in Roseau County, and of these, 143 were taken in the two years mentioned." The maximum home range of the least weasel is two acres and a weasel seldom travels farther than ten rods from its burrow according to Polderboer (1942:146) who, in the period December 20, 1939, to January 2, 1940, studied four least weasels and one long-tailed weasel on a 144 acre farm in Butler County, Iowa. BehaviorOf the voice, Llewellyn (1942:441) records that his captive specimen taken in Virginia uttered a shrill shriek when seizing prey or when teased. When excessively annoyed the weasel also emitted musk. The sense of smell is used in hunting as was witnessed by George L. Fordyce; he observed a least weasel following the scent of a Peromyscus and saw the least weasel overtake and kill the mouse (Seton, 1929 (2):637). At a nest in a clover stack, in Manitoba, Criddle (1947:69), on December 27, 1946, found the least weasel "to have been rather remiss in its sanitary habits as its pile of dung was almost, or quite, touching the nest and only just to the side of its entrance." There were 117 voids. EnemiesThe great-horned owl, barn owl and long-tailed weasel are to be counted as enemies since Nelson (1934:252) found the fur, skull and other fragments of the skeleton of a least weasel in one of 26 pellets of the great-horned owl in Wisconsin; Handley (1949:431) found the skull and other skeletal remains of a least weasel in one of 22 pellets of the barn owl in Virginia; and Polderboer, Kuhn and Hendrickson (1941), in Iowa, found the remains of a least weasel in the den and scats of a Mustela frenata. A domestic cat in Michigan killed a least weasel (Dearborn, 1932B:277). FoodMice are killed by the least weasel biting into the back of the head and neck according to Allen (1940:460) who reported upon the growth of five young, from Michigan, that he had in captivity. He further states that a weasel was able to kill a mouse in 30 seconds. One large Microtus introduced into the cage slept with a weasel for several days and ate parts of the mice that the weasel killed but then the weasel killed this mouse! Llewellyn (1942:440-441), in writing of a captive from Virginia, says: "When a live mouse was placed in the cage, the weasel sprang upon it almost instantly. Grasping the mouse by the back of the head, the weasel bit its victim through the skull several times in rapid succession and held on with its sharp teeth. The sound of the teeth piercing the bone was distinctly audible at a distance of several feet. During this interval the weasel hugged the mouse closely with its fore legs and pressed it firmly to its belly through a kicking motion of the hind legs. The hold on the back of the head was not relinquished until the mouse was dead. The killing took only a few seconds. Upon releasing the mouse the weasel usually came to the front of the cage and inspected the observer for an interval of several seconds after which it returned to its prey and began its meal at once. Sometimes the blood would be licked from the wound in the back of the head or perhaps an ear would be chewed a bit and the blood licked off, but never did the weasel 'cut the throat' of its prey and 'suck the blood.' "The weasel ate the head and brain first, beginning at the back of the head and working forward. Just before reaching the nose the process was reversed and eating then proceeded from the base of the skull toward the tail of the mouse. The tip of the nose, maxilla with teeth, and the tail seemed to be the parts least preferred; they were not eaten when an abundance of food was present. At no time did the weasel place its front feet on the mouse in an attempt to hold it. A second or third mouse was killed immediately upon being placed in the cage even though the first one had not been consumed. The weasel, however, usually returned to the partially eaten mouse and finished it before starting on a new one. Upon completing a meal, especially if the meal had been particularly bloody, the weasel rubbed its chin on the bottom of the cage, scooting along and appearing more snakelike than normal. Whenever I attempted to remove a mouse, or partially eaten one, from the cage, the weasel hung to the mouse tenaciously, and often allowed itself to be lifted up in this manner. "In the six days that the weasel was kept in captivity it was fed 10 house mice having a total weight of 118 grams. As no food was given on one day, the amount of food eaten is probably slightly below the actual capacity of the animal. Since the weasel weighed only about 32 grams, the average amount of food eaten a day was slightly in excess of one-half the weight of the animal." Polderboer (1942:146-147) found in three dens, in Iowa, bits of Reithrodontomys (harvest mice) and Peromyscus maniculatus (deer mouse), and in the digestive tract of one least weasel there was a bone fragment and a few hairs of a deer mouse. In the account, given beyond, of a nest, Criddle (1947:69) records the Pennsylvania meadow mouse (Microtus pennsylvanicus drummondi) and the Gapper red-backed vole (Clethrionomys gapperi) as prey at Treesbank, Manitoba. The same author, concerning the same place, earlier (1926:199-200) wrote that in 1922 the meadow mouse, Microtus minor, "went into winter quarters in great numbers and its homes were well stocked with provisions ... all went well until the middle of February, 1923. Then, within a few days, each was taken possession of by a least weasel (Mustela rixosa) and the inhabitants were quickly destroyed. One dwelling was occupied by one of these weasels for about two weeks during which time I observed that it had dragged several mice over the snow to its temporary home. This residence was examined in April, and in it were discovered six dead Microtus minor, one Evotomys, the head of another, and at least six or eight remnants of small rodents including Microtus drummondi, these last remains being chiefly indicated by the hair-lined nest of the weasel. "The homes of 27 other vole communities examined at this time were all found to have been entered by weasels, the inhabitants having been killed and partly eaten. Moreover, the weasels had made the homes temporary centers from which they raided other rodent habitations in the vicinity. Thus from being an abundant animal this vole was reduced to insignificance in the course of a few weeks, while all other kinds of mice had suffered severely from the same enemy." An instance of predation on Peromyscus, revealing some of the methods of capturing prey, is recounted by Seton (1929 (2):636-637) who quotes a letter to him from George L. Fordyce, of Youngstown, Ohio, as follows: "While out in the field this morning (Dec. 26), walking along the bank of a ravine at the edge of our golf course, I saw a Field-mouse run out of the bushes into the rough grass that is just outside of the fair-green of the course. In another instant, what I thought at first to be a white Mouse came out at the same place. The Mouse ran into a wheel track, and disappeared under the grass, coming out about 6 feet from where it went in. The white animal followed through the same course, and when it came out, I saw that it was a small Weasel, very little larger than the Mouse, and that it was following the trail of the Mouse by scent. "For a time the Mouse ran in circles, and zigzagged about, often ... within 4 or 5 feet of the Weasel; but the latter seemed so intent on the trail, that it did not notice the Mouse to one side. After a time the latter started toward the open golf course; and when the Weasel reached the point where the trail was straight, it sighted the prey, made a sudden dash forward, and, although 25 feet behind, overtook the Mouse while it was going 3 or 4 feet. "For a few seconds, they seemed to fight, until the Weasel got the Mouse by the throat, and started for the bushes, dragging the body. When it came to within about three feet of me, I moved a little to see what it would do. It dropped its victim, and ran into the ravine. The Mouse had a drop of bright red blood in the center of its white throat. I waited near by for 15 or 20 minutes, thinking the Weasel might come back, but it did not show up again; even an hour later, the Mouse had not been disturbed." There are two suggestions, but no proof that I know of, in the literature that the least weasel eats insects. Abbott (1884:27-32—1st ed., 1884) gives considerable information on the food (some insects included) of the "little weasel" which he describes (op. cit.; 27) as having "a little pointed tail of a uniform brown color." Although this suggests Mustela rixosa, Abbott mentions on the next page (page 28) that a specimen of the smaller weasel measured six and a half inches from the tip of the snout to the base of the tail and that the tail itself measured two and a fourth inches to the tip of the last caudal vertebra. These measurements indicate that Mustela erminea was involved. Because of the uncertainty as to the species of Mustela involved, Abbott's interesting data on food, nest and behavior are not recorded in the present work. Seton (1929 (2):636) says that of several least weasels brought to D. Nicholson at Morden, Manitoba, most of them decayed so quickly that they could not be saved as specimens. To Seton this indicated that insects were an important part of the food of the weasels. In summary: Least weasels are known to eat harvest mice, deer mice, meadow mice and red-backed mice; it is suspected that they eat also insects. ReproductionPolderboer (1948:296) has taken six specimens in "northeastern Iowa [in] ... January and December—all males in winter pelage. None of these males showed signs of sexual activity; in all, the testes were retracted and diminutive in size.... A male least weasel in brown pelage was taken November 17, 1945, at Marion, Iowa. This specimen had large testes that had descended into the scrotum. The testes, when removed, were about the size of medium-sized garden peas. Microscopic examination of the testes and the vasa deferentia showed mature sperms to be present...." On July 1, 1917, in Clay County, Nebraska, a nest with four young was found (Swenk, 1926:321). On July 29, 1939, an adult and five young were plowed out of the ground in Allegan County, Michigan; one of the two young males weighed 40.5 grams two days after capture (Allen, 1940:459-460). On August 12, 1932, ten young with the mother, were found in Roseau County, Minnesota (Swanson and Fryklund, 1935:125). September appears to have been the month of birth of a specimen, no. 8472 in the Carnegie Museum, taken on November 24 in Pittsburgh, Pennsylvania. In October, a young least weasel is recorded from Pennsylvania (Winecoff, 1930:313). Early December was the time of birth of a specimen, approximately 10 weeks old, no. 88077, University of Michigan, taken on February 21 in Allegan County. On December 25, 1927, in Washington County, Pennsylvania, "five full-sized, though young ... animals were caught under the same pile of corn fodder" (Sutton, 1929:253). The first week of January seems to have been the time of birth of a juvenile, no. 88080, University of Michigan, taken in Livingston County, Michigan, on March 27, 1943, since the specimen is approximately seven weeks old. On January 15, 1929, in Washington County, Pennsylvania, four young with the eyes yet unopened were obtained from a nest (Sutton, 1929:254). On January 25, 1928, young, the eyes of which may not yet have been open, were taken from a den in Washington County, Pennsylvania, by Winecoff (1930:313), who records other young having been taken in the same month as well as in February. On March 10, a female from North Portal, Saskatchewan, gave birth to four young (Dunk, 1946:392). On April 18, 1916, four young, half grown, were taken in Nebraska (Swenk, 1926:317). On April 2, 1929, three young were found in Roseau County, Minnesota, according to Swanson and Fryklund (1935:125) who remark that: "The Pennsylvania and Minnesota records show that least weasels may be born any time from July to early February in the northern states." Now, with all of the above records available, it turns out that November, May and June are the only months in which young least weasels have not been reported. Of course some of the young, for which the ages were not specified, were born in preceding months. Even so, the data now available suggests that, in the United States, young least weasels may be born in every month of the year. The number per litter is 3, 4, 4, 4, 5, 5, and 10, yielding an average of 5. The rate of growth of the young has not been studied enough to allow of judging if it differs significantly from that of other species of the genus. Allen (1940:459-460), however, tells us that of the three young females and two young males captured on July 29, 1939, in Allegan County, Michigan, one male that was killed on July 31, 1939, weighed 40.5 grams. The male remaining alive increased from 46 grams (August 5) to 62.5 grams on September 20, having eaten 63 mice while in captivity. The females in the period of August 5 to September 4 increased in weight as follows: 41 up to 49 grams; 44 to 50 grams; and 47 to 58 grams, having eaten, by September 26, 60, 64 and 65 mice. Concerning a nest in which young were found, Sutton (1929:254) writes that on January 15, 1929, near Burgettstown, Washington County, Pennsylvania, an animal was seen to enter a small hole in a creek bank. After the observer dug in a distance of approximately six inches an adult, female least weasel was seen and obtained. Back of the animal, the hole, which turned sharply downward, was full of water. The weasel first seen was a female nursing young. A chamber, to the side of the hole, filled with dead grass, comprised a nest containing four young with the eyes yet unopened. Several nests occupied by adult least weasels or by least weasels that were old enough to shift for themselves have been found. Polderboer (1942:145-147) in the winter of 1939-40, on a 144 acre farm in Butler County, Iowa, found four least weasels living, singly, in burrows dug by moles and pocket gophers. The nests therein made by mice were used by the least weasels. Winecoff (1930:312-313) mentions one den in Pennsylvania that contained the remains of only mice, "and not a hint of a feather." Above, in the account of food of the least weasel, Criddle's (1926:199-200) account of the havoc wrought by least weasels among the meadow mice (Microtus ochrogaster minor) has been given. In this account he mentions the fur-lined nests of the weasels that had appropriated the homes of the Microtus. Criddle's (1947:69) later account of a nest at Treesbank, Manitoba, is as follows: "A Nest of the Least Weasel.—When a least weasel finds its way into a locality that has a large number of mice in it, it selects for its home one of their nests that has been made in a well concealed place. This it immediately starts to improve by lining it with hair plucked from its victims before eating them; and as long as sufficient numbers of mice remain in the district the weasel continues adding their hair to the nest, so that the thickness of its walls give one a good idea of the length of time it has been in use. The nest is not only used for sleeping in, as most of the food is consumed in it. Frozen mice are taken in to be thawed out and the weasel carries those it has recently killed in to prevent them getting frozen, or perhaps to have them warm for its next meal. "On January 27, 1946, my son Percy called my attention to a nest that he had just uncovered in a clover stack that we were using. This nest had originally been made by a Drummond's vole, Microtus pennsylvanicus drummondii, and taken from it by the least weasel, Mustela rixosa, the tracks of which had been noticed about the stack yard since the first snow in early November. "The nest had evidently been in use for at least three months and the continual additions made to its walls had been so great that they were nearly an inch thick of hair matted together so closely that it appeared to be felt. The hair alone weighed nearly 22 gm., so that with this for protection the weasel must have been warm and comfortable through the severest winter weather. Fig. 28. Map showing occurrences and probable geographic ranges of the subspecies of Mustela rixosa in North America. "In the nest were two red-backed mice, Clethrionomys gapperi, one of which had the base of its skull eaten out. No hair had been removed from either of them, but a Microtus lying in a side tunnel some feet away had the long hair plucked from its back and sides. In and close about the nest were found forty-three front parts of mice skulls which had evidently been discarded because of the sharp teeth in the maxillaries. Seven full stomachs and eleven hind feet of adult Microtus with parts of leg bones were disclosed in, or under, the weasel's bed and a few small bits of skin with hair attached were scattered among the plucked hair of the nest. "This weasel seems to have been rather remiss in its sanitary habits as its pile of dung was almost, or quite, touching the nest and only just to the side of its entrance. It was composed of 117 voids all of which contained much hair and broken bone. "Six other mouse nests found in the same stack, or others adjoining it, had been thinly lined with hair. One of these had two mice in it, a red-backed with its brain eaten out and a Microtus with some hair plucked from its neck. Another nest contained the front part of a skull with teeth and the hind feet and tail of a red-back. Besides the mice found in the nests seven others were discovered tucked away in side tunnels. One of these mice had most of the hair plucked from its back. Whether all these mice and nests belonged to the same weasel or not I am unable to say, but it is usual for them to have several nests in the area surrounding the one that is used as their headquarters or home." Mustela rixosa eskimo (Stone)Least Weasel
Remarks.—Among the earliest specimens preserved was one by Edward W. Nelson in the course of his explorations of the Upper Yukon, and one in 1874 by L. T. Turner from St. Michaels, Alaska. Bangs, in 1896 (p. 22) mentioned the occurrence of the species in Alaska, but it was not until 1900 (p. 44) that Stone named the subspecies, and then principally on the basis of specimens obtained two years before by E. A. McIlhenny. The large size, broad skull, light color and short tail are the distinguishing subspecific characters of the race eskimo, and the three characters first mentioned are distinguishing features also of the subspecies of Mustela erminea, namely arctica, which inhabits the same region. Possibly eskimo also will be found on Banks Island and the other Arctic islands between Alaska and Greenland, as is M. e. arctica; at the present time no specimens of Mustela rixosa are known from these islands although some race of rixosa would be expected to occur there. Animals from southern Alaska average slightly smaller than those from northern Alaska, and this decrease in size toward the south probably represents intergradation with M. r. rixosa. Further evidence of intergradation is furnished by the short tail of the specimen from 15 miles east of Atlin; in other particulars this specimen agrees with the subspecies rixosa to which it is here referred. Nevertheless, the short tail, and color pattern, namely reËntrant angle of white behind the eye, is to be seen in all Alaskan specimens examined in the brown pelage, even in no. 107591, from Tyonek on Cook Inlet, which Osgood (1901:69) and Swenk (1926:323) thought might not differ from the subspecies M. r. rixosa. Each of four male topotypes, hardly subadult in age, probably of a single litter, is much larger than any other specimen seen from Point Barrow. The basilar length, for example, is 31.9 as against 29.5, and the weight of the skull (with lower jaws) is as much as 1.5 grams, as against 0.93 in the heaviest of the other males. Initial examination of materials from Point Barrow raised the suspicion that two distinct species were represented—rixosa and a larger one possibly allied to M. nivalis of the Old World. Nevertheless, further study almost completely allayed the suspicion because the only difference discernible is one of size, and it is supposed that additional specimens will bridge the gap in size and show that M. r. eskimo at Point Barrow averages larger than the adult specimens now available indicate. The four large males of subadult age are nos. 42814-42816 and 42818 of the American Museum of Natural History. Of the fourteen adult and subadult skulls examined, two display lesions resulting from infestation of the frontal sinuses by nematode parasites. None of the young skulls show such infestation.
Mustela rixosa rixosa (Bangs)Least Weasel
Remarks.—As early as 1858 (p. 159) Baird recognized an individual of this race from Pembina, Minnesota, as pertaining to a distinct species. Although he used for it the specific name pusillus originally proposed by DeKay for a small weasel from the state of New York, Baird wisely noted that the specimen he described "may be different from the New York species...." After preparing this account, Baird included a second specimen, from Fort Steilacoom, Washington Territory, which he thought might be the same, but the differences that he was careful to point out, in the light of later knowledge, show it to be of the species Mustela erminea. Only a few other naturalists followed Baird in distinguishing the least weasel as a separate species until Bangs in 1896 (p. 21) clearly differentiated it and proposed for it the name Putorius rixosus, which continues in use today and applies to the species. The accumulation at the National Museum of Canada, through the energy of Dr. R. M. Anderson, of a good series of specimens from Saskatchewan in the general vicinity of the type locality allows for the first time an adequate conception of the amount of secondary sexual variation and individual variation and permits recognition of subspecific characters to differentiate between M. r. rixosa and the subspecies eskimo and campestris. In comparison with the subspecies allegheniensis the basis for segregation is less clear and will remain somewhat in doubt until additional adults of allegheniensis from, say, Pennsylvania, become available with accurate external measurements taken in the flesh and especially with complete skulls. Intergradation with the subspecies eskimo is suggested by the short tail of the specimen from fifteen miles east of Atlin, British Columbia; in other particulars that specimen, a skin-alone, agrees with the subspecies rixosa. Intergradation with campestris is indicated by increased size of some specimens from North Dakota, and is suggested with allegheniensis by the color of specimens from Wisconsin and Illinois. Three specimens from Winona County, in southeastern Minnesota, unfortunately are skulls-alone without external measurements. Also, two of these skulls are of young animals. The one adult, unsexed, is from Crystal Springs. Selected cranial measurements are: basilar length, 28.5; length of tympanic bulla, 10.9. These measurements accord with those of males of the subspecies rixosa to which the specimens from Winona County, therefore, are here assigned. The possibilities have not been excluded, however, that the adult is an unusually large female of the subspecies campestris or a male of allegheniensis that has tympanic bullae longer than average for that subspecies. Some hesitation is felt in assigning the specimens, 8 in all, from eastern Canada to the subspecies rixosa. The skin-alone from Eagle River and the skin, with part of the skull, from St. Michael Bay, are in transitional pelage and are of no help in appraising subspecific characters. The one adult specimen which does have a complete skull is from an island south of the Comb Hills. This animal in all respects agrees with selected individuals of M. r. rixosa from Saskatchewan, but each of the five other skins in summer pelage has spots of dark brown color on the breast. Only about one specimen in three of rixosa from Saskatchewan is similarly marked. Furthermore, on some of the specimens from eastern Canada the spots are larger than on any of the animals from farther west. The greater frequency of brown spots on the breast, the larger average size of these spots, and the darker average coloration of the upper parts are suggestive of geographic variation, the existence of which has to be proved by additional and more complete specimens from eastern Canada. For the time being, specimens from there are tentatively assigned to the race rixosa. Of 56 subadult and adult skulls only 3 (1 North Dakota; 1 Calgary, Alberta; and 1 Island S Comb Hills, Queb.) display lesions resulting from infestation of the frontal sinuses by nematode parasites. None of the young skulls shows such infestation.
Mustela rixosa allegheniensis (Rhoads)Least Weasel
Remarks.—Robert Kennicott's mention in 1859 (p. 245) of what seems to be this subspecies is the earliest reference to it that I can identify in the literature. He used the specific name pusillus and it was not until 1900 that Samuel N. Rhoads proposed the name Putorius allegheniensis. Since 1900, several records of occurrence have been published which have made the geographic range of this race better known. An adequate number of specimens has been gathered only from Ohio and from western Pennsylvania. Many from Ohio are without accurate external measurements taken in the flesh. The majority of the specimens from Pennsylvania owe their preservation to the willingness of local officials, who pay bounties on weasels, to save the skins of Mustela rixosa. These specimens ordinarily comprise the skin with locality but because the feet, external measurements in the flesh, and skulls are unavailable, the material is far from adequate and to give an accurate notion of the usual or average cranial characters of allegheniensis in Pennsylvania, skulls from there are especially desirable. A smaller percentage of the specimens from Ohio than from Pennsylvania have the brown color of the upper parts meeting on the underparts. Also, more of the specimens from Ohio are lighter colored and this suggests intergradation with the subspecies campestris and rixosa to the westward. From Pennsylvania 23 animals in brown pelage are available. In 5 there is a rictal spot at the angle of the mouth; in 5 the area is white and in 13 the brown color of the upper parts is continuous over the area in question. Only 2 of 23 have the upper lips white. Eight have the color of the upper parts meeting on the venter thus restricting the white of the underparts to the chin, throat, and pectoral region, and 6 of these have a white area in the inguinal region as well. The toes of the forefeet are white in 3 of 4 animals suitable for examination in this regard and the hind feet are marked with white in 3 of the 8 animals which have the hind feet preserved. Mustela rixosa in Pennsylvania parallels the species Mustela frenata in that in this relatively humid area of the northeastern United States the color of the upper parts is darker and the area of the dark-colored upper parts is increased at the expense of the area of the light-colored underparts. Also Mustela erminea in this same region (range of the subspecies Mustela cicognanii) shows the same tendency to darker color of upper parts and their extension in area at the expense of the area of the light-colored underparts, or was mentioned above. It is difficult to account for the seeming absence of the species from New England and all that part of Canada and the United States south of the St. Lawrence River and northeastward from Pennsylvania. The size of females of M. erminea cicognanii in that territory is so little more than in rixosa that the latter possibly cannot successfully compete with the erminea stock which may already occupy the ecologic niche to which rixosa is adapted. It will be remembered that in western North America in territory seemingly climatically suitable for rixosa it occurs no farther southward than the line below which M. erminea has become reduced to a size comparable with that of M. rixosa. Of 41 subadult and adult skulls assigned to this subspecies 24 have obvious lesions in the frontal sinuses evidently resulting from infestation by nematodes. More in detail, none of the specimens from Illinois (3 individuals), Pennsylvania (3 barely subadult), or West Virginia (2) displays lesions. From Wisconsin, Indiana, Virginia and North Carolina there is one specimen each and each specimen displays lesions. From Ohio, 17 of 23 specimens display lesions. From Michigan 3 of 8 specimens display lesions; 2 adults and one subadult have lesions and 5 subadults do not have lesions.
Mustela rixosa campestris JacksonLeast Weasel
Remarks.—In his revisionary treatment of the American races of Mustela rixosa, Myron H. Swenk (1926:313) credits Samuel Aughey with recording this animal, M. r. campestris, from Nebraska, as early as 1880, under the name Putorius pusillus. In 1908, Swenk recorded the animal from the same state under the name rixosus and in 1913 the race campestris was formally named by H. H. T. Jackson. On the testimony of a friend who had previously obtained several specimens for him, Swenk (1926:321) records the least weasel from Oshkosh, Garden County, Nebraska, which is a marginal record of occurrence to the southwest for M. r. campestris. At an early stage in the study of American weasels the writer examined the specimens from Nebraska saved by Mr. Myron H. Swenk and recorded measurements of them. However, at the time of writing this account the specimens were not available for examination and the account of coloration is accordingly incomplete. The large size, particularly the large external measurements, comprises the principal distinguishing character of this subspecies of the least weasel. Of the four adults examined from Iowa and South Dakota one exhibits lesions such as result from infestation of the frontal sinuses by nematodes.
MUSTELA FRENATA LichtensteinLong-tailed Weasel (Synonymy under subspecies)
Characters for ready recognition.—Differs from Mustela erminea, in regions where the two species occur together, by tail more than 44 per cent of length of head and body and by postglenoidal length of skull less than 46 per cent of condylobasal length in males and less than 48 per cent in females (see under characters of the species); from Mustela rixosa by presence of black pencil on tail, caudal vertebrae more than a fourth (2/5-3/4) of length of head and body, basilar length of skull more than 34 mm.; from Mustela africana by absence of thenar pad on forefoot, underparts without longitudinal, median, abdominal stripe of same color as upper parts, upper lips narrowly (rather than broadly) edged with color of underparts, longest facial vibrissae extending to or behind posterior margin of ear; presence of p2; more inflated (see pls. 23 and 30) tympanic bullae. Characters of the species.—Size large: Total length 300 to 550 mm.; tail two-fifths to seven-tenths of length of head and body, with distinct black pencil at end; caudal vertebrae 19 to 23; skull with long precranial portion; postglenoidal length, expressed as a percentage of the condylobasal length, less than 47 in females and ordinarily less than 46 in males; upper parts brown; light-colored underparts, in summer pelage, tinged with buffy or yellowish and continuous from chin to inguinal region; some subspecies (southwestern United States, MÉxico, Central America, and Florida) with white or yellowish facial markings which do not occur in any other American species of the genus Mustela. Geographic variation.—Forty-two subspecies are recognized, and the species is geographically more variable than any of the other 3 American species. Color, color-pattern especially on the head, relative proportions of the tail, hind feet, body including the head, and shape and size of the skull are the principal features in which geographic variation has been noted. The variation in the skull extends to the basicranial region (shape and size of tympanic bullae and related structures), interorbital region and preorbital region. Natural History.—Habitat and Numbers.—As has already been remarked, the long-tailed weasel is absent from the extreme desert of the southwestern United States and northwestern MÉxico. Possibly the absence of water to drink is the limiting factor. In southern Nevada the finding of weasels only in places that were well watered, even though small rodents suitable as food for weasels were even more abundant in the surrounding desert, supports this possibility that the absence of water to drink is the limiting factor. Also at Berkeley, California, in early December of 1927 in the canyon at the head of Dwight Way and in the autumn and winter of 1928 in Strawberry Canyon on the campus of the University of California, I trapped extensively for this species in different habitats and obtained, in all, four individuals no one of which was farther than 10 feet from water. The lesser cruising range of the individual weasel than of, say, the coyote, probably explains why, in an arid region, for example Pahranagat Valley, Nevada, only the meadow mice and their riparian associates are preyed upon by the long-tailed weasel whereas the coyote preys upon these riparian rodents and also upon the kangaroo rats and other rodents which are so abundant in adjoining habitats that are devoid of water. In areas where water is available every few hundred yards, no particular habitat seems to be avoided in summer providing there is food for the long-tailed weasel. In winter (January and March) there obviously was a choice of habitat, possibly occasioned by more abundant food or more satisfactory shelter, or both, in Centre County, Pennsylvania, where Glover (1943B) found the population density in the chestnut-oak habitat to be one weasel per 6.5 acres in areas of tree cuttings and slash and one weasel per 13.3 acres in the open forest. In the scrub oak-pitch pine forest type the population was one weasel per 26.4 acres in tree cuttings and slash and one weasel per 38.2 acres in the open forest. No weasel was found in an area of 9.6 acres comprising a wood lot, the edge of the forest, abandoned fence rows and an abandoned orchard. The two types of forest in which he did find weasels, 25 in all, comprised 381.6 acres. Glover's (op. cit.) data is the only precise information known to me on actual numbers of long-tailed weasels in a given area of any considerable size. Fluctuations which I elsewhere (1946:57) have designated as multiannual fluctuations occur in this species but seemingly not in the degree that they do in Mustela erminea. This difference between the two species is to be expected because M. frenata does not range so far northward toward the polar regions as does M. erminea and populations of most kinds of animals in the polar, at least in the arctic, regions are subject to more extreme and more regular fluctuations than are kinds of animals in temperate or tropical regions. Indication of the means by which decrease in the weasel population is brought about is afforded by Osgood's (1935:156) observations around Rutland, Vermont. In the late winter of 1934, tracks indicated that weasels left their usual haunts and hunted cross lots, vainly trying to find food. Testing of the small mammal population in the spring and summer of 1934 showed that it was at low ebb. In the fall of 1934 mice and shrews were abundant again but weasels seemed to be entirely absent. The decrease in the population of weasels lagged behind the decrease in the population of the herbivorous prey as did the subsequent increase; this, of course, is the normal relation of carnivorous species of mammals and their prey, at least in and above the Transition Life-zone. The average distance away from the central den which four weasels (sex unspecified) traveled in a single night at Ames, Iowa, was 312 feet; the maximum distance was 642 feet. These data were obtained in the winter of 1939 by Polderboer, Kuhn and Hendrickson (1941:115) who studied the tracks in the snow. In Manitoba, Criddle and Criddle (1925:143) noted that a female which lived in their basement often wandered more than half a mile away in search of food. In Michigan, Quick (1944:75) found the maximum distance traveled in one day (= night?) by a large male to be 3.43 miles although two miles was the average distance traveled by this individual. In 1942, from January 4 to March 4, in Centre County, Pennsylvania, Glover (1943B) studied tracks of 11 males and 10 females, in newly fallen snow, and ascertained that the distance traveled in a single night averaged 704 (60-2535) feet for the male and 346 (20-1420) feet for the female. The weasels in the open timber traveled farther per trip than those in the brushland and dense stands of trees. BehaviorAn adult female (now the holotype of Mustela frenata nevadensis) seen running across a field, and, I think, unaware of my presence, at every bound bent her back up so far that she reminded me of a measuring worm. For part of the time when running, the tail was held off the ground straight out behind, and then, for a while, inclined upward at an angle of about 45°. Another weasel that I saw in the daytime, and that I think was unaware of my presence, was bounding along among the Baccharis bushes on the south-facing slope of Dwight Way Canyon, Berkeley, California. This individual, at each bound, arched the back up so high as to remind me, again, of a measuring worm. The long-tailed weasel is a land mammal and unlike its close relative, the mink, is seldom seen in the water. That it can swim, however, is attested by the capture of one while it was swimming across the RÍo Ramos in MÉxico (Davis, 1944:381). Also, Green (1936), in May, in Gratiot County, Michigan, saw a weasel, running with a Peromyscus in its mouth. The weasel dropped the mouse, entered the water and swam to a hole among stones. More instances of climbing, than of swimming, have been reported in the literature for the long-tailed weasel. Seton (1929 (2):625) quotes William M. Graffius of Pennsylvania as having seen a weasel closely pursue a red squirrel nearly to the topmost branch of a large hemlock. When the squirrel loosed its hold and dropped into a stream, the weasel descended to the ground and caught and killed the squirrel when it emerged from the water. Pearce (1937:483), in central New York State, on July 29, 1931, watched a weasel chase a chipmunk up a black cherry tree ten inches in diameter, and noted that the first rush carried the weasel "straight up the trunk for approximately 10 feet, where it hesitated momentarily before continuing. Then, instead of climbing vertically, it made progress by traveling in short ascending spirals around the trunk, scarcely making 3 feet in height for each circuit of the tree. Upon reaching the limb by which the chipmunk escaped, the weasel followed out along this in the same spiral manner. This limb had a diameter of about 4 inches at its base and extended upward at an angle of perhaps 20 degrees above the horizontal ... it made its way head first almost down to the ground, using the same spiral mode of progress, but at a leisurely pace.... While traveling down the side limb it appeared practically to wrap its sinuous body around the limb." A male long-tailed weasel, from Colorado, which I kept captive was often fed freshly killed mice. These I thrust through one of the small openings in the wire mesh. The weasel quickly learned to seize any part of a mouse thus introduced and his tugging aided in getting the mouse into the cage. Occasionally a mouse too large to be got through the mesh had to be withdrawn. In such an instance, if the weasel had already had hold of the mouse, he would screech frightfully. I have heard no other vocal sounds from a weasel except a kind of purring. The sense of smell apparently is well developed; at any rate it is keen enough to allow the weasel to follow the trail of an intended victim by the scent left by the latter. Murie's (1935:321-322) account, for example, of a weasel pursuing a snowshoe rabbit gives clear evidence that the weasel relied on scent in following the rabbit. A captive male weasel obtained at Gainesville, Florida, stamped his hind feet when annoyed (Moore, 1945:259). A male from Colorado that I kept for months in a cage at Lafayette, California, was several times found in a sleep so deep that he was awakened with difficulty. Seton (1929 (2):629-630) writes: "In my small menagerie, I have had half-a-dozen Weasels of the New York species. Their sleeping dens are arranged so as to be easily and silently opened. Several times I have lifted the lid to find the weasel in a deep sleep—a sleep so profound that I had to poke him vigorously with a stick before he awoke, looked up, and rushed forth with a little puff of wrath, and a little puff of smell." Feces and urine were ordinarily deposited in one particular place by each of the captive weasels that I have observed. Hamilton (1933:294) records that a large male M. f. noveboracensis, in a week, averaged 10 evacuations every twenty-four hours, that urination immediately precedes defecation, and describes the feces as black or brown, long and narrow and often spiral-shaped owing "to the matted fur of some rodent that had been eaten." Quick (1944:77) writes, concerning four winter dens in Michigan, that "The latrines of weasels were in the entries of used dens and scats could be collected there by the handful." Polderboer, Kuhn and Hendrickson (1941:116) in the spring of 1939 at Ames, Iowa, gathered scats "from latrines found at the entrances of burrows and from latrine chambers found within burrows." Scats were found by them in the linings of some nests. Courage of a high order might be credited to the long-tailed weasel because individuals have attacked animals much larger than the weasels. Actually, however, in few if any of these instances was the motive for attack known. That a hawk was attacked is suggested by Soper's (1919:45) account of Mustela frenata noveboracensis wherein he repeats a story told to him of a hawk observed in unsteady flight, and obviously in distress, which when it plummeted to earth was with a weasel which escaped from the observer. Charles Tatham, Jr., of Cambridge, Massachusetts, according to Seton (1929 (2): 630, 631) observed one that attacked his dog. Persons and long-tailed weasels have figured in some rather strange encounters. For example, Oehler (1944:198) recounts that in the autumn of 1940 at Cincinnati, Ohio, an animal, mistakenly thought to be a chipmunk, was seen to dash into a hollow log whereupon pounding on the log brought out the weasel which bit and clung to the hand of one man whose companion was bitten when he attempted to free the man that was bitten first. Seton (1929 (2): 631) writes that on the night of September 5, 1897, on Roosevelt's old ranch, near Medora, North Dakota, a man turned over his saddle (which was lying on the ground) to dislodge what was thought to be a pack-rat. The animal was a long-tailed weasel which attacked him. It ran up his legs a number of times aiming at his throat before being killed by a dog. Criddle and Criddle (1925:146) wrote: "August 20, 1919.—A longicauda in the Insectary ran at me this morning apparently with a view to intimidating. It uttered a shrill cry while making the attack, but retreated after advancing within two feet." The same authors (op. cit.: 147) further write that a "Long-tailed Weasel was caught in a trap set for gophers, and, on being released by Miss M. Criddle, at once turned upon its liberator and bit savagely at her boot. It then moved a short distance away to a tub of water, where it drank thirstily, merely glancing at the observer from time to time while doing so, and then ran off out of sight. "Mr. T. Criddle records a similar experience. After liberating a large weasel from a trap, it immediately rushed at him and persisted in its attack with such ferocity that it was three times picked up and thrown, on each occasion to a greater distance, before it finally abandoned its offensive. "We have no record of a weasel making an unprovoked attack upon anyone." Wight (1932: 164) in Michigan, detected a weasel attacking a hen. The weasel fled at Wight's approach but returned and attacked him several times. Finally the weasel went around Wight to reach the hen. In Wight's words "There was no evidence of infuriation, but rather a well directed offense at the one object, regardless of its size, which stood between the weasel and an opportunity to satisfy its desire to kill, which was probably based upon the uncontrollable urge of hunger pangs." Weasels of each of the three North American species have been successfully kept in captivity. A type of cage satisfactory for keeping the animals in the laboratory is described by Bissonnette and Bailey (1940:761-763). Some of the captives used their teeth to break glass water-containers and to gnaw slivers of wood from the cages. Ingested slivers of wood and bits of broken glass caused the deaths of some of the captives. Weasels kept by me all were of the species Mustela frenata. They thrived on a meat diet but I was always careful to give them, every few days, if not each day, some small rodents entire, thinking that the bits of bone and fur ingested might, in some way unknown to me, keep the digestive tract in better condition than would flesh devoid of hair and bone. Three young weasels approximately the size of mice, in the Okefinokee Swamp of Georgia, were obtained by a hunter who, according to Harper (1927:303), raised them by feeding "milk for a few days, and then fresh meat." Litters of young born in captivity have been successfully raised by the mothers (Hamilton, 1933) and success in getting the animals to breed in captivity and to rear their young is recorded by Wright (1948A). He has found, however, that the majority of his captive adult males show no interest in mating when placed with females in heat. He, therefore, uses only selected males and when a female in heat is to be bred, he places one of his responsive males with her one day, another of his responsive males with her the second day and thus alternates a couple of males for three or four days. Even so, slightly fewer than half of the females which were thus bred produced young. A weasel in the white winter coat was used by Audubon and Bachman (1856:177, Quarto edit.) to drive rabbits out of their burrows in the same fashion that ferrets commonly are used. Although these naturalists refer to their animal as an ermine it probably was Mustela frenata noveboracensis, the long-tailed weasel. The animal's teeth (probably canines) were blunted and a long cord tied on its neck. With the aid of this weasel 12 rabbits were caught in one morning and more than 50 in four weeks. EnemiesLittle is recorded concerning enemies of weasels and it may be that other vertebrates are not an important factor in removing the annual increase. Errington (1935:195-198), in Iowa, found four, putrid weasels about dens of red foxes, Vulpes fulvus. No remains of weasels were found in the feces of the foxes and it appears that the foxes do not eat the weasels. The label on an adult female specimen of M. f. spadix from Boone County, Iowa, bears the date May 10, 1938, and the annotation, by T. G. Scott, "fox-killed." Bailey (1931:328) recounts that "Weller saw a coyote carrying one in its mouth" at an elevation of 11,500 feet in the Pecos Mountains of New Mexico. The type specimen, a young female, of M. f. peninsulae from Hudsons, Florida, according to Rhoads (1894:155) "... was caught in the woods by a cat." Barber and Cockerell (1898:189) mention one that was killed by a dog in Mesilla Park, New Mexico. Moore (1945:258) records the death of a weasel in Florida. Circumstantial evidence indicated that it was killed by the bite of a water moccasin. In the Biological Surveys Collection of mammals in the United States National Museum, the label with the skull of an adult male weasel, No. 160663, from Banning, California, carries the information that the skull was taken from the stomach of a Crotalus (rattlesnake). In reporting on a study of owl predation in Delaware County, Pennsylvania, Pearson and Pearson (1947:143) mention that "weasels are found throughout the county but ... were never eaten by the owls." The Uinta spermophile at some places and times probably is a prey sought by the long-tailed weasel but Warren (1924:265) records Citellus armatus repeatedly chasing weasels in August, at Camp Roosevelt, Yellowstone National Park, and how the ground squirrels at one time ignored the weasel even when it came within a few inches of a squirrel. Warren (1932:71), on August 2, 1931, at Grand Mesa, Colorado, obtained a large male weasel with two porcupine quills in it; one was near the mouth and another "in the skull." Osgood (1935:156) writes that near Rutland, Vermont, a male weasel "taken in April, was heavily parasitized and had several short porcupine quills embedded in its neck, head, and shoulders." The remainder of Osgood's account implies that the weasel may have turned to porcupine because the normal food for weasels was scarce at the time. Porcupine quills, then, are a hazard for weasels although it is unlikely that the porcupine is ever to be classed as an enemy of the weasel. An accident of another sort, which must at the very least have been annoying to the weasel that suffered it, was recorded by Soper (1921:37). The animal had a stick lodged crosswise between the fourth upper premolar teeth. The recorded actions of several kinds of animals which are too small to be dangerous to the weasel suggest that they recognize that the weasel is a danger to them. Borell and Ellis (1934:21) mention that a weasel in Nevada caused a great disturbance among the chipmunks. Long (1938:250) heard pikas give evidence of terror by a peculiar cry when a weasel was in a rock slide occupied by the pikas. Seton (1929 (2):629) writes "On June 14, 1915, as I prowled around the south side of the lake on my homeland at Greenwich, Conn., my attention was called to a pair of song sparrows and a male towhee that were noisily mobbing a Weasel, twittering around and darting at him, as though they knew full well his evil ways. The weasel paid little heed, but soon dived from sight in a stone wall." No account has been found of an American weasel or ermine rolling, tumbling and frolicking in a manner that aroused the curiosity of birds to a degree which permitted the weasel to come within leaping distance of the birds. Accounts of such behavior are on record for the English stoat (ermine). Food and HuntingWeasels are active both in the daytime and at night. Whether the time of activity varies with the season, with the locality, with the sex or with other conditions, I do not know. Adult, live, free-living, actively moving weasels that I recall having seen all were observed in the daytime: two were in Alameda County, California, two were in White Pine County, Nevada, one was in Scotts Bluff County, Nebraska, and one was in Laramie County, Wyoming. I recall ten adults, from the same three states, and one from Washington State, that got into my traps; two of these certainly got in the traps in the night; one certainly got in the trap in the daytime; the other eight were found in traps which may have caught the weasels either in the night or in the daytime. Soper (1946:136) in speaking of M. f. longicauda north of the International Boundary in Canada remarks that it has the "habit to some extent of hunting at all times of day." Criddle and Criddle (1925:144) in writing of Mustela frenata longicauda in Manitoba record that "The shrill cry of a rabbit [Lepus americanus] in the dark is nearly always due to the weasel's attack. Indeed, we have often watched the latter at work during the twilight hours. First would come the almost noiseless run of the small rabbit with its characteristic dodging and this would be followed by the appearance of the agile foe which, at times, would leap high over obstacles and at others move swiftly beneath them. Then there would follow intermittent cries of the rabbit as the weasel secured a temporary hold of its quarry, for be it noted that this hunter apparently bites anywhere to begin with and it is probable that the blood made to flow acts as an aid to tracking as well as weakening the prey. Several similar close encounters might occur before the rabbit would be finally overcome, but weasels are very persistent when they once get into contact with their victims and it is therefore very seldom that the latter escape. In killing, they either penetrate the brain with their teeth, or dislodge the vertebrae behind the head." These and more than two score other observations which record the time when weasels were seen make it clear that some were active at night and that some were active in the daytime. As to the routes traveled while the weasels are hunting, Quick (1944:77) says of four individuals that he studied in Washtenaw County, Michigan: "The weasels appeared to prefer hunting certain coverts with noticeable regularity, but rarely cruised the same area on two consecutive nights." The killing technique of fifteen captive Mustela frenata noveboracensis was studied by Glover (1943A). For the weasels he released 19 mice, 3 brown rats, 6 cottontails and 4 ring-necked pheasants. Most of the mice were killed by a bite on the back of the head, with the body and legs of the weasel hugging the back of the victim. "The weasel shoved the prey in close to the stomach with the hind legs, and the kill was made in a reclining semi-curled-up position." On each of the rats (Rattus) an initial grip was secured at the base of the ear. When the rat rested, a new hold was taken by the weasel. Finally the weasel secured a hold at the base of the skull and near the ear, and a light crushing sound followed. Four of the six cottontails were killed by bites on top of the head and ear; two cottontails succumbed from neck wounds. In three instances, neither of two weasels could be induced to make a determined attack on the cottontails or to kill them. At times the cottontails proved to be able opponents for weasels by striking out with their front feet and by kicking with their strong hind legs. In killing the pheasants the teeth of the upper jaw of the weasel pierced the top of the braincase and the teeth of the lower jaw entered the region of the auditory process. The forelegs hugged the neck of the pheasant, the body of the weasel was extended in a riding position on the back of the bird and no amount of kicking or rolling dislodged the weasel. Polderboer, Kuhn and Hendrickson (1941) describe a cottontail cached by a weasel as having the muscles of the neck severed from the region behind the right mastoid process and noted "that hemorrhage in the region of the right jugular vein had occurred." Concerning the methods of killing mammals smaller than cottontails, the accounts by Nichols and Nichols (1935:297-299) and that by Svihla (1931) corroborate Glover's (1943A) account, as do also the accounts of Miller (1931B:164) and Moore (1945:257). The latter says that his captive male, from Gainesville, Florida, customarily bit its rodent prey at the base of the skull and used the feet to manipulate the live prey. Miller (loc. cit.) emphasized that his male weasel (M. f. longicauda) grasped where it could, used its snakelike body to coil over the prey and shifted the grip of its teeth to the nape of the neck or back of the skull. The captives that I have had [one from Salt Lake City, Utah; three from Contra Costa County, California; and the same individual reported upon by Miller (1931:150)] customarily employed the techniques of killing small rodents that were described by Glover and Miller (loc. cit.). Allen (1938:225-229) experimented with the ability of four different males of M. f. noveboracensis from Michigan to kill adult cottontails. The method used was to place the weasel in a cage of quarter-inch hardware cloth approximately three feet long, two feet wide, and two feet high. The bottom of the box was covered with several inches of straw. One cottontail was offered to each weasel. In two instances the weasel attacked and bit the cottontail, was struck by the hind feet of the cottontail, retired from the attack and died a few hours later as a result of the blows of the cottontail's hind feet. In the other two instances the weasel rendered the cottontail helpless by severing the neck muscles from the skull. Subsequently an incision made by the weasel, in each of the two instances gave access to blood on which the weasel fed until it was full, in one instance by licking "blood as a cat laps milk." One rabbit was subdued in 10 minutes and the other in 15 minutes. Allen (op. cit.) points out that cottontails form a considerable portion of the weasel's food and thinks that they are killed in burrows more easily than they were in the cage. In writing of the three species of weasels, including Mustela frenata, found at Treesbank and vicinity, Manitoba, Norman Criddle and Stuart Criddle (1925:143, 144), in my opinion, correctly explain the killing of more prey than weasels need. "The fact that weasels frequently kill many more animals than they require for immediate use has been universally interpreted as a lust for killing—a supposition which we believe to be quite erroneous. It is true that weasels often kill more than they need, but the surplus is not necessarily wasted because the animals always store it for future use, in much the same way as do badgers, minks or skunks, and with the same object in view as squirrels have in gathering nuts. We have observed many such stores, but as far as our observations go, the habit of killing in excess occurs much more prominently in the late summer and autumn months than in the spring. Indeed, we have no records of excessive spring slaughter and this indicates that the supposedly blood-thirsty habit of weasels is no more a lust for killing than is the woodsman's foresight in providing his larder with meat for the winter months. It should be noted in this connection that members of the weasel family, when undisturbed, do not leave their victims scattered about, but carefully store them away, and in many instances the bodies are buried with earth or taken under ground to preserve them. We suspect that this instinct for preserving food for future use accounts for most of the excessive killing by carnivorous animals instead of this latter indicating an aimless desire for slaughter which would unnecessarily deplete the food supply of the future. This instinct, however, does not seem to be as definite as that of some rodents, and there is no doubt that much of the stored meat decays before it can be utilized." Criddle and Criddle (1925:146) note that a weasel in the vicinity of Treesbank was carrying a rat [Rattus] and that "Two small punctures in the throat were the only evidence of the manner in which its death had been brought about." Considerable information has been recorded concerning the food of Mustela frenata and a little information is on record as to kinds of foods not taken that could have been taken. For example, Ingles (1939:253, 254) on May 14, 1938, near Shasta City, California, noted that nestlings of russet-backed thrushes were ignored by an adult weasel and four young weasels which were feeding instead on meadow mice and a mole. Howard (1935:322, 323) records that a weasel in Michigan which carried bits of meat from beef bones on a porch ignored a red squirrel which drew on the same food supply but which retreated to the end of the porch when the weasel appeared. Quick (1944) records that in the winter of 1940 on a 640 acre area in Washtenaw County, Michigan, four resident weasels did not kill any of the 10 rabbits or several pheasants but subsisted on smaller animals. Glover (1943A) thought that M. frenata kills only a few adult cottontails in the wild. To judge from these observations, M. frenata chooses small mammals as prey in greater measure than it does birds or larger mammals. Records of prey taken, attacked or pursued by Mustela frenata include the following: Broad-footed mole (Scapanus latimanus).—One was fed on by an adult M. frenata and four young, on May 14, 1939, "near Shasta City," California (Ingles, 1939:253, 254). Dusky shrew (Sorex cinereus).—A female weasel, at Majestic, Long Island, N. Y., was shot when carrying a Sorex cinereus that had a small hole in the top of its head (Nichols and Nichols, 1935:297-299). Big short-tailed shrew (Blarina brevicauda).—One was taken from the stomach of a weasel (Hamilton, 1928:249). Townsend ground squirrel (Citellus townsendii).—Alcorn saw a weasel five miles west of Fallon, Nevada, carrying a squirrel (Hall, 1946:192). Richardson ground squirrel (Citellus richardsonii).—The attempted capture of one of these squirrels in Saskatchewan is recorded by Seton (1929 (2):625). Belding ground squirrel (Citellus beldingi).—Grinnell, Dixon and Linsdale (1937:233) recount that at Tuolumne Meadows, California, a weasel killed a ground squirrel of this species. Thirteen-lined ground squirrel (Citellus tridecemlineatus).—Errington (1936:406, 407) found a den in Palo Alto County, Iowa, on June 22, 1934, where he collected 32 fecal pellets. Sixteen samples contained thirteen-lined ground squirrels, 9 contained rabbits, 9 contained mice (7 Microtus, 1 Peromyscus and 1 unidentified); red-winged blackbirds and unidentified fringillids were represented as also were ground beetles, grasshoppers and other insects. One red-winged blackbird lay near the entrance of the den. Franklin ground squirrel (Citellus franklinii).—Sowls (1948:126) records that at Delta, Manitoba, a weasel was observed killing one of these squirrels and that "the weasel had taken the squirrel from its hibernating burrow as evidenced by tracks in the snow." On July 19, 1917, in the vicinity of Treesbank, Manitoba, T. Criddle saw a weasel attacking one of these ground squirrels which was in mortal terror and squeaking continuously. Eventually the squirrel was thrown on its back "and would have been speedily killed but for an interruption" (Criddle and Criddle, 1925:146). Golden-mantled ground squirrel (Citellus lateralis).—On August 15, 1941, along the Kaweah River in Sequoia National Park, Boyer (1943:99, 100) saw a weasel chasing a Citellus lateralis; three or four times the weasel grasped the back of the neck of the squirrel which each time threw off the weasel until the two, weasel after the squirrel, plunged into the river. The squirrel, bleeding at the base of the skull, was rescued and entered a hole; the weasel got out of the water and under a rotting log. Follett (1937:365) at 2 p.m. in Plumas County, California, saw a weasel have hold of the lower jaw of a golden-mantled ground squirrel near its throat. Alcorn watched a weasel chase a golden-mantled ground squirrel in Nevada (Hall, 1946:192) and Grinnell and Dixon (1919:681) record that on August 4, 1911, near Monache Meadows in eastern Tulare County, California, a weasel pursued, captured and killed a golden-mantled ground squirrel. Eastern chipmunk (Tamias striatus).—Pearce (1937:483) in central New York State, on July 29, 1931, saw a chipmunk scamper up a tree pursued by a weasel. Chipmunk (subgenus Neotamias).—Stanford (1931:363) on November 11, 1931, at Fish Lake, Utah, saw a weasel pursuing a chipmunk. On August 5, 1910, "near Independence Lake," Nevada County, California, Louise Kellogg recorded that a weasel seized and ran off with a chipmunk (Grinnell, Dixon and Linsdale, 1937:233). Allen (1938:228) observed that a chipmunk (whether Tamias striatus or T. minimus not specified) was killed in 30 seconds whereas 10 to 15 minutes were required by the caged, male Mustela frenata noveboracensis to kill a cottontail. Red squirrel (Tamiasciurus).—Seton (1929 (2):625) records the capture of one in Pennsylvania, and Grinnell, Dixon and Linsdale (1937:232), at Cisco, California, saw one closely pursued by a weasel. Flying squirrel (Glaucomys).—Burroughs (1900:77, 78) records remains of one of these squirrels along with the remains of other animals in a food cache of a Mustela but his account does not make clear whether Mustela frenata or Mustela erminea was the species of weasel involved. Northern pocket gopher (Thomomys).—In "July, 1939, near Stillwater [Nevada], Alcorn pursued ... [a] weasel and caused it to drop ... a pocket gopher [Thomomys bottae] which was about two-thirds grown" (Hall, 1946:192). Grinnell, Dixon and Linsdale (1937:233) write that "at least twice, weasels in the [Yosemite] Valley were seen carrying pocket gophers." Relative to Thomomys talpoides in the vicinity of Treesbank, Manitoba, Criddle and Criddle (1925:146) record that on September 11, 1918, an individual of Mustela frenata longicauda took seven pocket gophers dead.... It seized the rodents by the middle of their back and held them high while carrying them away. They were stored in a gopher burrow some two hundred yards distant. On February 17, 1921, "Came across the marks of a weasel carting some object over the snow. An investigation revealed a recently-killed pocket gopher with its captor still in possession." Criddle (1930:279), at Aweme, Manitoba, "frequently observed this weasel [M. f. longicauda] ... carrying a pocket gopher to its larder, and twice it has been encountered in mid winter with freshly killed gophers in its possession." The evidence already presented that weasels levy heavily on pocket gophers is strengthened by the many references in the literature to weasels having been caught in traps set for pocket gophers in the burrows of those rodents and by the many statements, not quoted here, that living quarters of weasels are in burrows made originally by pocket gophers. For example, the present writer, in an account of the Mammals of Nevada (Hall, 1946:191, 192), has said of the long-tailed weasel, Mustela frenata nevadensis, that "All the three dens that were excavated ... were originally burrows of pocket gophers.... Although we have found weasels in many situations in Nevada, ... they most often were obtained from the burrows of pocket gophers." Excluding the weasels taken by Alcorn, more specimens of the remaining lot were caught in traps set in the burrows of pocket gophers than by all other means combined. All of the 22 weasels taken by Alcorn [within a radius of 10 miles of Fallon] were obtained in gopher traps. Mexican pocket gopher (Cratogeomys).—At Chalchicomula, 8000 feet, Puebla, Nelson (1918:470 and letter dated March 9, 1928) saw a weasel fastened to a pocket gopher. Nelson obtained the pocket gopher and found that its neck muscles were torn loose from the skull. Grasshopper mouse (Onychomys).—Barber and Cockerell (1898:189) found remains of this mouse in the stomach of a weasel at Mesilla Park, New Mexico. White-footed mice (Peromyscus).—Green (1936) saw a weasel in Gratiot County, Michigan, in May, carrying a Peromyscus. Quick (1944:76), in winter, in Michigan, found one dead, probably killed by a weasel. From Washtenaw County, Michigan, Quick (1944:77) examined 294 scats of free-living weasels and found Peromyscus in 189 scats, Microtus in 83, small birds in 20, red squirrel in 3, and hair of weasels in small quantities (probably from the animals which deposited the scats) in 36. He concludes (op. cit., 78) that the winter food was 65 to 70 per cent Peromyscus, 23 to 33 per cent Microtus, and 2 to 7 per cent small birds. Wood rats (Neotoma).—A female long-tailed weasel weighing 250 grams was taken one mile north of Kent, Texas, while eating a Neotoma albigula (Davis and Robertson, 1944:263). A wood rat house under observation by Vestal (1937:364) in Contra Costa County, California, was invaded by one weasel which ate two adult wood rats (Neotoma fuscipes) and one young. In the same area he saw a weasel in a wood rat nest some months later (Vestal, 1938:5). Three miles east of Reno, Nevada, on May 13, 1936, W. B. Richardson watched a long-tailed weasel carrying a half-grown round-tailed wood rat (Neotoma lepida) across a rock slide (Hall, 1946, 192). Harper (1927:303) records three wood rats [Neotoma floridana] and two cotton rats [Sigmodon hispidus] found dead in the den of a female weasel and her three young in the Okefinokee Swamp of Georgia. Another female and three young approximately half grown were found in the swamp in a hollow pine log. Contents of the den as described to Harper were nearly a peck of wood rats, whole and in pieces; remains of several kinds of birds including robins and quail, and a piece of joint snake (Ophisaurus ventralis). Meadow mice (Microtus).—Polderboer, Kuhn and Hendrickson (1941), in 1939, at Ames, Iowa, identified "A total of 118 items ... in 97 winter scats and 48 in the 38 spring scats." Their combined data are as follows: Polderboer, Kuhn and Hendrickson divide their data into two categories, winter and spring. Items recorded in winter but not in spring are house mouse, tree sparrow, and grasshopper. Items recorded only in spring were pocket gopher and least weasel. The samples of cottontail and least weasel all were from the scats of one large male weasel. Of a total of 14 pheasants, 24 quail and 35 cottontails on the 160 acres involved in the study only two cottontails appear to have been killed by the weasels—really by one weasel of four which lived on the area. Food items taken from the nests (3) and adjacent caches of food in the dens, were as follows: meadow mouse, 30; short-tailed shrew, 4; pocket gopher, 2; deer mouse, 2; least weasel, 1; tree sparrow, 1. The authors remark that the abundance of several prey species does not cause the weasels to ignore the shrews which are said to be distasteful to carnivores. Two horned larks, apparently killed by weasels, were found on the 160 acre area studied; the horned larks were not in caches of food, nor were remains of horned larks found in scats. Dearborn (1932:34, 37) for Michigan, on the basis of contents of (37?) intestinal tracts and "feces collected partly in winter and partly in summer" found that, by frequency of occurrence, mammals comprised 83 per cent of the food, birds 10 per cent and insects 7 per cent. Frequency indices for the genera of mammals in percentages of food items of all kinds were as follows: Microtus, 31 per cent; Peromyscus, 24 per cent; Sylvilagus, 14 per cent; Sorex, 7 per cent; Blarina, 5 per cent; Scalopus, 2 per cent. Criddle and Criddle (1925:146), for the vicinity of Treesbank, Manitoba, record that on October 3, 1913, a weasel was seen to take a field mouse down a hole. They add (op. cit.:147) that "Once while ploughing, we observed a Long-tailed Weasel carrying a field mouse...." Ingles (1939:253, 254), in June, 1938, near Mt. Shasta City, California, found an adult and four young weasels which fed on several Microtus montanus montanus. Green (1936) in May, in Gratiot County, Michigan, in the vicinity of a nest in which there were four young weasels, found "several" dead Microtus. Hamilton (1933:330) records that in New York State a male weasel, on April 5, 1932, at Ithaca, had eaten a Microtus and that in May, 1927, a female weasel was seen carrying a Microtus in its mouth. Hamilton's (1933:333) study of the contents of the digestive tracts of bodies of weasels obtained from fur trappers and fur buyers enabled him to publish the following "Frequency Indices of Mammal Genera in Fall and Winter Food of 163 Mustela noveboracensis": Microtus, 33.6 per cent; Sylvilagus, 17.3; mammals undetermined to genus but principally mice, 17.1; Peromyscus, 11.3; Rattus, 9.1; Blarina, 5.9; Sciurus, 2.7; Tamias, 1.0; Condylura, 0.8; Ondatra, 0.8. Grinnell, Dixon and Linsdale (1937:233, 234) quote W. Fry concerning a weasel which reared six young at Giant Forest, California, in 1919, as follows: "This parent weasel, after the birth of her young, remained at the premises for a period of thirty-seven days; during which time, from actual count, the following numbers of mammal species fell victim to her: mice [genera not specified] 78; gophers 27; moles 2; chipmunks 34; wood rats 3; ground squirrels 4. This is a total of 148 animals for the ... thirty-seven days ... not a bird was captured during the period." Rats (Rattus).—Criddle and Criddle (1925:146), on the farm at Treesbank, Manitoba, record a long-tailed weasel, on July 2, 1918, running away from the farm buildings carrying a rat; July 11, 1919, "Two longicaudas ... have been seen running off with rats on several occasions."; July 11, 1920, "There are two large weasels about the buildings[;].... Each has been noted with rats and this afternoon one of them was seen running into the woods carrying a rat, followed by two excited swallows." The authors (op. cit.:147) add "In the fall of 1924, Mr. A. Cooper, a prominent poultryman of Treesbank, observed a large weasel carrying a freshly killed rat which it stored below ground and then returned towards the poultry-house, causing no little apprehension to the owner. Within a short time, however, the weasel reappeared with another rat which it hid as before. In this way several rodents were accounted for during the afternoon, and Mr. Cooper assures us that the weasel 'kept up the good work for some days'." Hamilton (1933:330) in New York State in May, 1927, saw a male weasel in possession of a rat. Big jumping mouse (Zapus major).—In the Warner Mountains of California, on Parker Creek, H. C. Bryant frightened a weasel that dropped a freshly killed jumping mouse (Grinnell, Dixon and Linsdale, 1937:232). Snowshoe rabbit (Lepus americanus).—Adolph Murie (1935:321-322) writes that: "Four miles north of Funkley, Minnesota, early on the morning of November 13, 1921, ... watched from the top of a 30-foot spruce a weasel. .. hunting a varying hare.... The ground was covered with six inches of fresh snow ... both animals ... [had] their [white] winter pelage. "My attention was first attracted to the hare as it came hopping steadily but unhurriedly from the north. Directly in front of me, about 75 feet from the tree I had climbed, the hare crisscrossed back and forth at various angles over an open area about 20 feet in diameter. After producing a maze of tracks, the hare 'froze' near one edge of the pattern. In a few minutes the weasel appeared, all his faculties focused on the warm trail. Expertly he followed its convolutions, passing at times within a few feet of the watching hare. Not until the weasel had followed every turn of the trail to within three feet of its termination did the hare skip off. It came out to the road almost directly below me, turned at right angles northward and was soon out of sight. At the road the weasel lost the trail, ... and then ran parallel with it, once more in hot pursuit. "Ten minutes later the hare emerged from the north as before, came on directly to the tracked-up area, and continuing its stratagem, leisurely hopped about to leave its zigzag trail. Then it sat down quietly to wait.... The weasel['s] ... nose led him through the network with little trouble. He was almost upon the hare before it jumped off and followed the same path [as] ... before.... "The hare had to show his big heels [a third time] ... as the weasel approached him. This time the weasel failed to follow.... After examining a few brush heaps he vanished into the woods behind me." Seton (1929 (4):723, 724) writes that in December of 1886 in the sandhills northeast of Carberry, Manitoba, he saw a weasel chasing a snowshoe rabbit which took refuge near his feet under the sleigh and so escaped the weasel. Thurber (1940:356) mentions a month-old varying hare that was rescued from a weasel and of approximately the same size as the weasel. Criddle and Criddle (1925:146) for the vicinity of Treesbank, Manitoba, record "August 21, 1921.—Heard cries of a small rabbit at dusk to-night, which investigation showed was being attacked by a large weasel. The rabbit was later carried to the weasel's store chamber below ground." They record further (op. cit., 146, 147): "November 8, 1924.—Shot a bush rabbit and left it lying. Two hours later [it] ... was found to have been dragged beneath a brush pile and partly eaten. Innumerable weasel tracks left no doubt as to the identity of the thief." In describing a weasel that wintered in a nest in a threshing machine, the same authors (op. cit.:143) say that no bird remains were found in the pile of approximately three pounds of droppings adjacent to the nest. In a store chamber some 140 yards away from the nest, two bush rabbits (Lepus americanus) had been dragged to the entrance and numerous smaller rodents were taken below ground. The rabbits were buried beneath the snow and eaten as necessity arose. Narrow selectivity on the part of the weasel in choosing food is almost always shown in instances where the food of weasels has been studied. For example, the weasel which lived in the threshing machine ate rodents and rabbits and not poultry although the weasel had ready access to the poultry building. The weasel which lived in the bag of feathers in the basement of Stuart Criddle's house ignored grouse, approximately 20 in number, in favor of other non-avian food. Cottontail (Sylvilagus).—Polderboer, Kuhn and Hendrickson (1941) mention that one of 4 weasels which they studied on a 160 acre area at Ames, Iowa, in 1939, had a cache of food in a pocket gopher burrow 10 rods distant from the weasel's den. The cache contained only two cottontails, one partly eaten. Leopold (1937) records seeing a Mustela (probably a long-tailed weasel but possibly an ermine) kill a third-grown cottontail by biting it at the base of the skull. Leopold describes the blood sucking or licking, suggesting that he shared the popular misconception that weasels suck blood. The supposition that weasels suck blood has been refuted by many observers, for example by Svihla (1931). My own observation of captives makes me think that weasels do not suck blood. Seton (1929 (2):626) quotes B. H. Warren as seeing a weasel dragging a freshly killed, still warm, rabbit that contained nine embryos almost ready for birth. A young rabbit was seen being carried by a weasel in Hidalgo County, Texas, in March, 1935 (Mulaik, 1938:104). An instance of a cottontail being chased in June in South Carolina is recorded by Hamilton (1933:330). Addy (1939:372, 373), in Virginia, on August 14, 1939, shot a large weasel which was pursuing a Sylvilagus that was only a foot and a half ahead of the weasel. The rabbit stopped when a shot was fired and permitted itself to be stroked and petted. Tracking showed that the weasel had chased the rabbit for a half mile. On November 20, 1942, at Lake James, Indiana, a weasel was seen by Grosjean (1942:443) attacking a "young rabbit" in the throat of which the weasel had made five large holes from which there was no obvious bleeding. Seton (1929 (4):798) recounts that in 1910 at Base Lake, Michigan, F. C. Hicks saw a cottontail with a weasel hanging to its legs rush to the cottage. When only four feet from Hicks the weasel loosed its hold and the cottontail escaped under the cottage. Burroughs (1939:253) on May 14, 1939, in Saginaw County, Michigan, records that a young cottontail weighing between 200 and 250 grams was carried from the nest and killed. Burroughs was attracted first by the "hissing scream" of the weasel, strode toward the sound, flushed an adult cottontail, and discovered the empty nest from which the weasel had taken the young cottontail. Brush rabbit (Sylvilagus bachmani).—Vestal (1937:364) in Contra Costa County, California, found a brush rabbit that appeared to have been killed by a weasel. Reptiles.—Grinnell, Dixon and Linsdale (1937:234) recount that in July, 1889, in Wilson Canyon, near Pasadena, California, a weasel killed a red racer by severing the backbone of the snake. In April, 1935, in Hidalgo County, Texas, a half grown bull snake (Pituophis sayi sayi) was regurgitated by a young weasel. Russell (1930:504, 505) has recorded finding in California a male weasel and a king snake (Lampropeltis getulus boylii) three feet five inches long in mortal combat. The weasel killed the snake but the weasel, incapacitated by the conflict, was easily picked up by hand and was also saved as a specimen. Wild birds.—In the spring of 1940, in Washtenaw County, Michigan, one bobwhite, of 10 bobwhite living on a 640 acre area, was killed by one of four weasels that lived on the area. No other quail was killed there. The one unfortunate bird was killed in the mouth of an abandoned den where the quail roosted (Quick, 1944:76). A male weasel, subspecies M. f. effera, was seen by Booth (1946:439) attempting to enter the nesting hole of a pair of flickers, Colaptes. One song sparrow (Melospiza melodia), and one slate-colored junco (Junco hyemalis) were recorded by Quick (1944:76) as killed by weasel in Michigan. Chicken (genus Gallus).—Quick (1944:78) writes that in one year (1938-1939) weasels were reported to have killed 1.03 per cent of all chickens in one township of Washtenaw County, Michigan, and that of the total damage to all kinds of poultry, 59 per cent was done by weasels. Weasels entered 19 per cent of the chicken coops on the study area. Farmers killed 68 per cent of the weasels seen in barn yards. Spring and summer were the seasons in which most of the weasels were observed in barn yards. Internal evidence in Quick's (op. cit.) account leads me to suspect that some losses of poultry were charged to weasels when Rattus was actually responsible. Criddle and Criddle (1925:146), quote a neighbor in the vicinity of Treesbank, Manitoba, as recording that on October 29, 1917, "A weasel last night made its way into our fowl-house, the door being inadvertently left open. The weasel killed eleven fowl, some of which were dragged into the yard. All the largest fowls were selected, the pullets remaining untouched though they were in the majority. Next night the weasel dug a hole beneath the building and killed a hen and two cocks, returning for another during the day, making a total of fourteen in all." Criddle and Criddle (1925:146) remark that the weasel proved to be a large one, probably an old male. The same authors (op. cit.:147) record that at their farm at Treesbank, Manitoba, on January 31, 1925, "A Long-tailed Weasel killed three hens last night, and rather severely bit a cock about the neck. This, or another weasel, had been around the farm-yard for sometime (The specimen was a large male).... "In the fall of 1924, Mr. A. Cooper, a prominent poultryman of Treesbank, observed a large weasel carrying a freshly killed rat which it stored below ground and then returned towards the poultry-house, causing no little apprehension to the owner. Within a short time, however, the weasel reappeared with another rat which it hid as before. In this way several rodents were accounted for during the afternoon, and Mr. Cooper assures us that the weasel 'kept up the good work for same days'. "Being a farmer of many years' standing, Mr. Cooper has naturally lost some poultry through the agency of weasels, but while he remarks that 'there are good as well as bad actors among weasels', he has the practical good sense to recognize the value of an efficient ratter even though it be a weasel. "Our sister, Maida Criddle, writes under date of March 4, 1925: "'There is another weasel (longicauda) in the fowl-house, a well-behaved one this time. It came and took a piece of meat out of my hand quite nicely, which it carried down a hole and then came and sniffed all over my mitt to see if there was any more. I thought it had been killed when I visited the farm buildings next day as there was a strong smell of musk on the cat and in the fowl house, but the weasel was there as cheeky as ever. It got hold of my skirt twice and tried to pull me down its hole. I think it wanted the cloth for a bed, as it was taking straw and other material down the burrow. The poultry were very frightened at first, but they are getting used to the weasel's presence now'." In commenting on the economic role of the long-tailed weasel in Manitoba, Criddle and Criddle (1925:145) write as follows: "Supply and demand are prominent factors in governing our weasels' food habits. The two smaller species, as we have already pointed out are so dependent upon mice for a living that they increase or diminish with the fluctuation of these creatures. The Long-tailed Weasel, however, is not so easily checked by the temporary disappearance of any particular kind of game. If mice are scarce it devotes greater attention to gophers or bush rabbits and if these are not in sufficient numbers to satisfy its appetite, the animal raids a poultry house as a last resource. In nine years out of ten, this weasel will find sufficient food about the fields and woods, but on the tenth it may be obliged to temporarily turn to domestic animals. It is at such times that the weasel is seen and its deeds recorded. A thousand mice may have been killed in the meantime, but the destruction of half a dozen hens is alone used as evidence of the weasel's economic standing. "In the last twenty years we have permitted weasels to frequent the farm buildings at will and the poultry house has been no exception. In that time rats and mice suffered severely from the weasels, while the total number of poultry taken were six. Many times that number, however, have been killed by rats. "When we review our experiences of the past, we are astonished to find what few poultry have been killed by weasels. Our own losses in forty-two years have not exceeded fifteen birds and even these were usually eatable. There have been reports of losses from time to time from neighbors, but on looking into details we find that there are very few farmers who have experienced more than three separate occasions of weasel depredation and the total loss per farmer in the last thirty years does not, we are sure, exceed ten birds. This is surely a remarkably small payment to weasels in general for the great good done by them in killing rodents. "We wish to point out, too, that only the exceptional weasel becomes a poultry killer. In most cases apparently it is a fully-grown male that does the killing. There are exceptions, of course, but when we see a large weasel actively engaged in rodent hunting within a few feet of a brood of newly hatched chickens and not even looking at them, we must at least pause to ask if this animal is the enemy that we were taught to believe it to be." A suggestion that weasels sometimes obtain the prey killed by hawks is offered by Criddle and Criddle (1925:147) who write: "Hawks are not always the aggressors, as is shown by an incident reported by Mr. H. L. Seamans, of Lethbridge, Alberta. Mr. Seamans noted a large buzzard suddenly fly straight upwards from a fence post, and then alight upon another one some distance away. A little while afterward this bird once more arose in the same manner as before, and presently repeated the performance again. An investigation then followed and revealed that a Long-tailed Weasel was following the hawk from post to post. "We should hardly expect a weasel to attempt to capture a bird of the above type. On the other hand, it is possible that these animals might be able to startle a hawk sufficiently to cause it to drop its prey, which would thus provide food for the weasel." The following frequency index is compiled from the foregoing data on prey of Mustela frenata.
More significant than the above compilation, of course, are the results of careful studies of the food of the long-tailed weasel in restricted areas. Examples of such studies are those of Polderboer, Kuhn and Hendrickson (1941) and Hamilton (1933:333). According to Hamilton's (1933:332) observations on captive weasels, "There seems to be little relative difference in the amount they eat, regardless of their activities. "In general, more food is taken in summer than in winter. Usually about a third their weight every 24 hours is eaten, but a growing young weasel will consume much more. A young male noveboracensis, weighing 145 grams, consumed an entire chipmunk, fur and bones, weighing 85 grams, in 24 hours. A day later it ate all of a partly grown rat, 105 grams, in the same length of time." Moore (1945:253) records that a captive male that he obtained at Gainesville, Florida, consumed, on the average, between 63 and 70 grams of flesh and blood per day. The weasel itself weighed approximately 320 grams. Sanderson (1949:413), concerning seven young weasels from Manitoba, that he raised in captivity, writes: "From the fifth to the seventh week of age, they consumed approximately 22 per cent of their body weight per day; from the eighth to the tenth week (just before reaching mature size) they consumed approximately 24 per cent; but after reaching maturity they consumed only 18 per cent. When given all the food they would take in one day, they ate as much as 40 per cent of their body weight." Criddle and Criddle (1925:143, 146) say that weasels drinking at a bird trough "held their mouths very close to the water and as far as we could see, lapped the liquid up with rapid movements of the tongue. As a rule, after drinking, they would merely spring to the ground and vanish amid a bunch of scolding birds, but occasionally we have seen an animal slowly drag itself through the water and follow this performance by some rapid gambols, or a quick run, a method of drying which most of us have practiced in our youth." According to Hamilton's (1933:332) observations on captives, "Weasels are great drinkers, and while they take but little at a time, about 25 c.c. is drunk by a large animal during a day...." ReproductionPhilip L. Wright's several papers (1942A, 1942B, 1947, 1948A, and 1948B) reporting on his detailed studies of Mustela frenata (subspecies oribasus and longicauda) in captivity have yielded a large share of the precise information that we have concerning breeding and reproduction in this species. He has found that a single litter, of up to 9 young is born in the spring, usually in April. At three months of age the females "are full grown." The young males remain sexually immature during the first summer but the young females, as well as the females which are more than a year old, come into heat in the midsummer and are bred by the adult males. After a long period of quiescence lasting for several months, the embryos resulting from these matings become active in early spring and develop to full term in less than 27 days after they become implanted. The adult males are sexually active from April into August, when the testes are at maximal size and are conspicuous in the scrotum. A gradual regression takes place starting in August and extending into September. By October the testes may be fully regressed and the molt to white may start in this month. The white winter weasel, of either sex, is sexually inactive. The testes of the sexually active male in early spring and late summer are seven to eight times the size of the fully regressed testes. Females which had borne and suckled young were first found to be in oestrus 65 to 104 days after birth of the young. Lactation lasts for approximately 5 weeks. In 18 litters the length of the gestation period varied from 220 to 337 days with an average of 279 days. The female in heat has the vulva much swollen and she will remain in this condition for several weeks if not bred. Wright (1948A) describes the actual mating as beginning with a scuffle after which the male grabs the female by the scruff of the neck with his teeth and holds her until she becomes subdued when he clasps her lower abdomen with his front feet and arches his back over her posterior regions. The two animals remain locked in this position usually for two hours and sometimes for longer than three hours. If the animals are left together, copulation may take place again on the same day or upon succeeding days. Hamilton (1933:316-321) writes of a freshly born M. f. noveboracensis that it "... was pink and much wrinkled. The wetness ... did not entirely obscure a few sparse, rather long, white hairs ... over its back and head. It had the pronounced and extraordinarily long neck of the adult." At one day of age the average weight of six individuals in the litter was 3.1 grams, which is 3 per cent of the weight of the adult female and 1-1/2 per cent of the weight of an adult male. At two weeks of age "The silky white hair ... obscures the general flesh color of the skin, evident a week earlier. The hair on the back of the head and neck, also over the shoulders, is slightly longer than that of the back ..." but there is no crest or mane or pompadour at this or any other age such as characterizes the juvenal ermine. When 21 days old one young male "hurried from the nest chamber and commenced to eat some meat." At three and a half weeks "They are all eating small pieces of meat.... The canine teeth have made their appearance in both the upper and lower jaw, but just a hint of the incisors show. Some of the cheek teeth are through, as the meat appears to be thoroughly masticated by the little ones." On the 36th and 37th days the eyes opened. Sanderson (1949:415) found that a litter of seven young of Mustela frenata longicauda, from Manitoba, raised in captivity, "reached the peak of their growth" at approximately ten weeks of age. Several nests have been found. In Manitoba, Sanderson (1949:412) excavated a burrow at the mouth of which he had trapped the adult female and in which he found eight young approximately five weeks old. The "burrow was about three inches in diameter, with two chambers at a depth of twelve inches. One of these was empty, the other contained the young. The two surface-openings were but two feet apart and the entire burrow was no more than three feet long.... The meager nest material consisted entirely of finely chopped grass. There was no mouse hair present, no accumulation of fecal material, and no storehouse containing food." Charles O. Handley has written me that on January 25, 1929, on the Sinkola Plantation, Thomas County, Georgia, he investigated the living quarters of a family of five weasels, four of which had been shot five days before by a hunter. According to the hunter each of the four which had been killed was approximately two-thirds the size of one which escaped into a hole in the ground. Handley found that the weasels had been using as headquarters a burrow in the trunk of an old uprooted oak as well as a nearby gopher burrow. The burrow in the oak was approximately ten feet long and had been excavated in the rotten wood. In a distance of fifty feet along the gopher tunnel there were several used openings with pathways leading away from each. On February 6, Handley, with the help of a friend, trapped a large male weasel near this place. Criddle and Criddle (1925:143) describe a female which, one winter, slept in a bag of feathers in a basement of a house occupied by one of the authors; another weasel in winter made its headquarters in a threshing machine. The nest of the latter "was somewhat roughly constructed and consisted of a convenient bunch of straw and chaff under the cylinder." Harper (1927:303) in the Okefinokee Swamp of Georgia dislodged a weasel from the house of a wood rat and was told of a den found in the swamp "in the trunk of a hollow cypress tree" from which a mother weasel and three young "about the size of mice" were obtained. "The bed contained, I suppose, a bushel or more of rabbit hair, rat hair, and squirrel hair. It looked like it must have been used as a den for several years, although there was no stink that I could detect except the musk from the old Weasel." Another female and three young approximately half grown were found in a hollow pine log. Between January 6 and April 12, 1940, on 640 acres of land, in Washtenaw County, Michigan, four weasels were studied and each weasel used only one den in this period (Quick, 1944:78). Criddle (1930:279) remarks that M. f. longicauda at Aweme, Manitoba, often makes its temporary headquarters in the burrows of pocket gophers (Thomomys). A female and three young weasels were found by Shaw (1921:167) using a nest of a mountain beaver in the burrow of that animal. Green (1936), in May, in Gratiot County, Michigan, saw a weasel enter a hole under a decayed log and investigated finding four young weasels in a nest mostly of Microtus fur. In the early part (winter and spring) of 1939, at Ames, Iowa, Polderboer, Kuhn and Hendrickson (1941) studied four weasels living in four separate dens on 160 acres typical of Iowa farmland and excavated three of the dens. One den was in a weed patch in an old mole run. The nest chamber, approximately nine inches in diameter and six inches below the surface of the ground "was filled with grasses packed in a layer-like formation. In the center of this mass was a nest hollow lined with patches of mouse and shrew fur. Beneath this layer of fur and at the sides of the nest were skins, various bones, and skulls of partially eaten mice and shrews ... scats [were in the nest].... At intervals, layers of clean grass had been laid over the filth of the former bed, thus giving the nest a stratified appearance." A second den, of a large male, was in a field of sweet clover two feet high in the former burrow of a Franklin's ground squirrel. The nest cell, seven inches in diameter and nine inches below the surface of the ground, "was lined with grasses mixed with much rabbit and mouse fur. Some scats, and bones and fur of mice and shrews were matted together in layers at the bottom of the nest." When this den was abandoned the male weasel occupied, for a month, another burrow, 20 rods distant, of a Franklin ground squirrel, in the field of sweet clover. The nest cell measured 11 by nine inches and was 11 inches below the surface of the ground. "Two nest layers were present. The first, composed chiefly of coarse straw and grass, had apparently been occupied at some time by a spotted skunk.... On top of the skunk nest was the weasel nest composed of fine grasses, mouse fur, and skeletal remains of mice." Relation of the Sexes to each other and to the youngQuick (1944:75) writes that on March 28, in Michigan, he found the tracks of a male and those of a smaller animal, supposedly a female, meeting. The two "then led along the fence for about 18 chains and both entered the den of the male.... Only the tracks of the smaller weasel left the den on the same date. Observation on April 12 showed that the large male still occupied the den." I am at a loss to explain this behavior since breeding would not be expected to occur in late March and since I suppose that the male and female do not live together except in the breeding season. Consequently, I wonder if the sign was wrongly read.
Hamilton (1933:328), however, writes that M. f. noveboracensis is to "be found in pairs when caring for the young. During mid-May, 1927, I several times saw a male of this species carrying food to a den of young ones." Green (1936), in May in Gratiot County, Michigan, remarks that while he was uncovering and examining a nest of four young weasels, two adults ran about excitedly and one removed a young weasel. In instances where several nearly full-grown young have been obtained from one den it has been my experience (Hall, 1946:191) that the only adult trapped there was the female; no adult male was found or in the one instance when found he was living alone in a den 200 yards away from the den of the female and her young. Data are too few to warrant a definite conclusion about the extent to which the male aids in rearing the young, but I have wondered if he might not do so when the young were less than half grown and then live alone when they were more than half grown. Mustela frenata noveboracensis (Emmons)Long-tailed Weasel Plates 16, 17, 18, 31, 32 and 33
Comparisons of the skull with those of M. f. olivacea, M. f. spadix, M. f. primulina, and M. f. arthuri, are made in the accounts of those subspecies. As compared with that of M. f. occisor the skull of adult male noveboracensis, is of smaller average size with relatively (to basilar length of Hensel) lesser mastoid and zygomatic breadths. In addition to the zygomatic arches of noveboracensis being less widely bowed outward they seem to be more rounded posteriorly. Comparisons of subadult females indicate that these differences exist in the females as well as in the adult males. Remarks.—The earliest of the post-Linnaean references to this weasel mostly were under the specific name erminea in the belief that the American animal was the same as the larger of the two common species of weasel in the Old World. The name noveboracensis, now in use for this subspecies, was applied in 1840 and since that time the males usually have borne that name; the females, because they are smaller, were more frequently confused with some other species. Audubon and Bachman in 1853 even proposed the name agilis for the female in the mistaken belief that it was a species distinct from the male. After 1896, when Bangs correctly classified the weasels of the eastern United States, the males have been correctly identified and the females, except by a few authors, likewise have been correctly named. Because many early American naturalists did their first collecting of mammals in the geographic range of noveboracensis, the person who examines labels of specimens of this subspecies can find data written in the hand of Spencer Fullerton Baird, Theodore Roosevelt, and other naturalists famous for their work as scientists or accomplishments otherwise. The material is more nearly adequate than is that of many other subspecies and the number of specimens is exceeded—and only slightly—by that of the subspecies nevadensis, which like noveboracensis has a relatively large geographic range. Intergradation with Mustela frenata spadix is indicated by subadult males from western Wisconsin, namely, one from Gordon, three from Colfax and one from Meridean. Linear measurements of the teeth of these specimens are exactly intermediate between those of spadix from Elk River, Minnesota, to the west, and noveboracensis from, say, Beaver Dam, Wisconsin, to the east. The specimens from western Wisconsin show approach to spadix also in that the length of the tooth-rows and breadth of the rostrum are slightly greater than in noveboracensis from farther east, say, Beaver Dam, Wisconsin. Indeed, animals from as far east as Beaver Dam itself might be thought of as showing some approach to spadix. Although, along the eastern seaboard, the upper lips, with rare exceptions, are the same color as the underparts, farther west, in Michigan and Wisconsin, the lips more often than not are white. Animals from Beaver Dam have slightly shorter black tips on the tails, broader extent of the light color of the underparts and females average slightly larger than typical noveboracensis, say, those from Massachusetts. Each of these differences reflects characters found better developed in the spadix-longicauda stock to the west. Toward the southern part of its range where noveboracensis meets M. f. olivacea there is a marked increase in yellowness of the underparts. This coloration of the underparts, since it is not so well marked in the northern part of the range of noveboracensis, might be regarded as showing intergradation with olivacea and primulina, each of which has far more intensely colored underparts than does noveboracensis. Excepting this increase of yellow on the underparts, however, there are few if any characters of noveboracensis which undergo marked change as approach to the range of olivacea is made. Indeed, the characters of noveboracensis remain constant to within a relatively short distance of the geographic range of olivacea. Notwithstanding the state of affairs described above, intergradation seems to take place. Three specimens referred to noveboracensis but which at the same time are regarded as intergrades with olivacea are as follows: No. 28.300, Charleston Museum, from five miles east of York, South Carolina, is an adult female with a badly crushed skull. In external measurements the specimen agrees with noveboracensis. The underparts, as regards color and width, are intermediate. The general proportions of the skull and tympanic bullae agree with those of noveboracensis but the skull is larger than in any female of true noveboracensis and approaches that of olivacea. The same can be said of a young female, no. 80, Ohio State Museum, from Roswell, Georgia. Another female, no. 171559, U. S. Nat. Mus., from Lookout Mountain, 1500 ft., Fort Payne, Alabama, is barely subadult. The external measurements are nearer those of olivacea. The color and narrowness of the underparts are typical of noveboracensis. The proportions and especially size of the skull show approach to olivacea, though they are nearer to noveboracensis when all features are taken into account. In the northern part of its range individuals of noveboracensis attain larger size than farther south. This tendency reaches its extreme, in males at least, in M. f. occisor of Maine. Specimens of noveboracensis from the Adirondacks of New York average larger (see cranial measurements on page 418) than those from farther south, and thus approach occisor in size as well as in geographic position. Also, occasional individuals which strongly show characters of occisor are found even farther south than the Adirondacks of New York. This is true of no. 96518, U. S. Nat. Mus., ? ad., from Lunenburg; Massachusetts. The animal has a large skull of relatively great width much as in occisor, although its external measurements, relative length of tail and long, terminal, black brush place it with noveboracensis rather than with occisor. Of a pair of specimens from Ossipee, New Hampshire, the male, no. 77108, U. S. Nat. Mus., has a long (175 mm.) tail, and short (60 mm.) black pencil as in occisor, although otherwise it is referable to noveboracensis. Still another specimen, a subadult male, no. 4193, Mus. Comp. ZoÖl., from Upton, Maine, has a longer (51 mm.) hind foot than noveboracensis although it otherwise agrees with that subspecies. As remarked by Bangs (1899:55), other than fully adult specimens from the range of occisor are "troublesome," and would not be selected as distinct from noveboracensis if placed in a series of that subspecies, say, from New York State. In view of the facts that several specimens from intermediate localities combine the characters of noveboracensis and occisor, that noveboracensis in the northern part of its range averages larger than it does farther south and thus approaches occisor in size, and that occasional large specimens resembling occisor in several, but not all, features sometimes crop up in the northern part of the range of noveboracensis, it appears that noveboracensis and occisor intergrade. Therefore they are treated as two subspecies of the single species, Mustela frenata. Intergradation with M. f. primulina has been commented on in the discussion of that subspecies. Female, no. 159980, U. S. Nat. Mus., from Golconda, Illinois, has many characters of primulina but two young males from there agree better with noveboracensis. Examination of 283 adult and subadult skulls for malformation of the frontal sinuses revealed only ten that were not obviously malformed. Two were from New York, one from Massachusetts, one from Pennsylvania, and six from the 52 specimens from Michigan and Wisconsin. In addition, skulls of many young and even juveniles were malformed.
Mustela frenata occisor (Bangs)Long-tailed Weasel Plates 16, 17, 18, 31, 32 and 33
Remarks.—Excepting a specimen in the Academy of Natural Sciences of Philadelphia, obtained in 1893, and two in the Boston Society of Natural History, obtained in 1925, I have seen no material of this subspecies in addition to that examined by Bangs at the time he prepared the original description in 1899. Anderson (1945:56, 57) records a specimen, Canadian National Museum Catalogue Number 18426, from Kamouraska County, Quebec, as of this subspecies and thinks that occisor occurs north of Maine "locally to south side of lower St. Lawrence River in Quebec; probably also in western New Brunswick." So far as the available material of occisor permits one to judge, it is distinguished from noveboracensis by a combination of characters no one of which invariably can be relied upon as diagnostic. Employing adult males, average differences indicate that M. f. occisor is larger in each of the external and cranial measurements; tail relatively longer; black tip of tail relatively shorter; mastoid and zygomatic breadth relatively greater and zygomatic arches more nearly square posteriorly. Considering the large number of specimens of noveboracensis which are available in comparison with the few of occisor it is not surprising that some noveboracensis should be found which exceed in size those of occisor. This is the case as regards the basilar length of a very old male, no. 96518, U. S. Nat. Mus., from Lunenburg, Massachusetts. Also, the skull is actually broader than any of those of occisor. However, this specimen is much older than any occisor examined. In a female, no. 4260, Mus. Comp. ZoÖl., from Liberty Hill, Connecticut, the skull is longer (but narrower) than in either of the two available females of occisor. The average differences pointed out above which characterize this extreme northern population of noveboracensis-like weasel in comparison with true noveboracensis without much question are geographic variations. Whether or not these variations are of a degree sufficient to warrant nomenclatural recognition is debatable. With equally scanty material from other regions I have not named variations seemingly as great as those shown by occisor. The paucity of material of occisor is a handicap in making a decision in this instance. Each of the adult and subadult specimens, except the one from Perry, shows malformation resulting from the infestation of the frontal sinuses with parasites.
Mustela frenata primulina JacksonLong-tailed Weasel Plates 16, 17, 18, 31, 32 and 33
Compared with the skull of M. f. noveboracensis from Massachusetts, that of the male of primulina, in dorsal view, is seen to be shorter anteriorly to the postorbital processes and to have a more marked postorbital constriction. In lateral view the dorsal outline of the skull of primulina is less concave in the postorbital region. In ventral view the skull of primulina is seen to be wider across the mastoid processes and zygomatic arches but the most pronounced difference is in the tympanic bullae. In noveboracensis each bulla is scooped out on the anterior part of the medial face and appears to be narrower anteriorly than posteriorly whereas in primulina the anterior part of the medial face is not scooped out but is moderately inflated and the bulla appears to be of uniform breadth anteriorly and posteriorly. By actual measurement the breadth of the bulla averages 59 per cent of its length in primulina but only 50 per cent in noveboracensis. Other respects in which the skull of the male of primulina differs from that of noveboracensis are as follows: Linear measurements of teeth more; relative to the basilar length, the length of the tooth-rows averages more, whereas the interorbital breadth and orbitonasal length are less. When skulls of females are compared, each of the differences mentioned above is found to apply, except that the degree of difference is in some parts greater, for example, in the tympanic bullae. In primulina, the bulla is in general like that of the male noveboracensis, whereas in the female noveboracensis it is less inflated, especially anteromedially, shorter, relatively narrower, and in ventral view projects little or none below the squamosal floor of the braincase. The breadth of the bulla averages 51 per cent of its length in primulina but only 47 per cent in noveboracensis. The bullae project below the basioccipital on the average, for a distance of 2.9 millimeters in female primulina and only 2.3 millimeters in female noveboracensis. In primulina the temporal ridges are well developed and fuse to form a low sagittal crest, but in noveboracensis the ridges are absent. Also, in primulina the mastoid processes project farther laterally beyond the braincase. The skull of female noveboracensis is much lighter than that of primulina. Average weights of the two are 1.7 and 2.2 grams. The skulls of females of primulina and noveboracensis differ more than do the skulls of males. Compared with the skull of spadix, that of the male, and the female, of primulina averages smaller in every part measured. Expressed in percentages of the basilar length, the two depth measurements of the skulls are not significantly different, but, excluding the measurements of the bullae and teeth, the other cranial measurements are less. The main difference in relative proportions is in the tympanic bullae which average only a half millimeter shorter in males of primulina and one and one-tenth millimeters shorter in females. The bullae are, therefore, relative to the basilar length, longer in primulina. The skull of primulina, then, differs from that of spadix mainly in smaller size and relatively longer tympanic bullae, especially in males. Compared with the skull of M. f. longicauda, that of both sexes of primulina averages smaller in every part measured, except in males where the length of the tympanic bulla, and breadth and length of M1 are the same or slightly larger in primulina. Relative to the basilar length, the length of the tympanic bullae, and in females only, the depth measurements are greater in primulina but all the others, in both sexes, are less. These ratios reflect the relative narrowness of the skull of primulina. Upon direct comparison the narrowness is especially noticeable in the interorbital region, mastoid region, tympanic bullae, and across the zygomata. Compared with the skull of M. f. neomexicana that of both sexes of primulina averages smaller in every part measured. Excepting the measurements of the teeth, most of the other measurements are constantly larger. Relative to the basilar length, the length of tooth-rows and length of tympanic bulla are more, but excepting the depth measurements, the others are less. Still other differences are, in primulina, less well-developed sagittal crest, anterolateral corner of bulla rounded rather than "square," and in males a transversely convex rather than flat interorbital region. Compared with M. f. frenata and M. f. texensis, the skulls of males of primulina differ in being smaller in every part measured but relative to the basilar length, have longer tooth-rows, a lesser zygomatic breadth and are less constricted interorbitally. Compared with the skull of M. f. olivacea, those of both sexes of primulina average smaller in every part measured, have shallower (dorsoventrally) tympanic bullae, a lower sagittal crest and slightly weaker postorbital processes on the frontals. Relative to the basilar length, the several cranial measurements are about the same. Comparison of the skull with that of M. f. arthuri has been made in the account of that subspecies. Remarks.—The first specimens of this race known to have been preserved in study collections are one in the United States National Museum, taken at Bridge, Carroll County, Missouri, many years ago by J. Burbage, and less than a dozen specimens preserved before 1900 from eastern Kansas in the University of Kansas Museum of Natural History. In 1913 Hartley H. T. Jackson bestowed a name on this animal on the basis of two specimens taken by him in southwestern Missouri. Later, through the efforts of Charles D. Bunker, and his associates at the University of Kansas, nearly 100 specimens were saved from eastern Kansas, principally from Douglas County. In the course of the present study, Lawrence V. Compton obtained a topotype for the California Museum of Vertebrate ZoÖlogy, and with the assistance of Mr. B. G. Roberts, a good series of specimens from Boone County, Arkansas, was preserved in the same museum. In the early years of the 20th Century, the late B. H. Bailey at Coe College, Iowa, collected specimens from that state. The specimens from these several sources suffice to give a relatively clear idea of the characters of this subspecies. Mustela frenata primulina is closely related to M. f. noveboracensis, from which, on the average, it differs in the lighter color of the upper parts of the summer coat, in the more intense coloring of the underparts, and in certain cranial features pointed out above. In the southern part of its range, however, noveboracensis has the underparts only a little less intensely colored with yellow than primulina. Also, the skull of the one topotype from 7-1/2 miles southeast of Carthage, a subadult male in brown, winter pelage, is almost exactly intermediate between that of noveboracensis from Massachusetts and primulina of Douglas County, Kansas, and Boone County, Arkansas. M. f. primulina often has the underparts white in winter, as does this topotype which agrees with the average of noveboracensis in small size of teeth and narrowness across the mastoid processes and zygomatic arches. However, it agrees with primulina in shape and relative size of the rostrum. It is almost exactly intermediate in shape and width of the tympanic bullae. Three other males, but no females, all in winter pelage, are available from eastern Missouri. Of the two from Silex, Lincoln County, one is nearer noveboracensis and the other nearer primulina on the basis of cranial characters. The third specimen, from four miles south of Lesterville, so far as I can determine by examination of individual cranial characters and tabulation of results, is exactly intermediate. Final decision on the proper allocation of specimens from the parts of Missouri represented can best be made when skulls of females are available. From the fact that the skull of the female referred to noveboracensis from Golconda, Illinois, shows almost as many characters of primulina as of noveboracensis, it is judged that females from as far west as Silex and Lesterville, Missouri, will show even more characters of primulina and so be referable to that form. If this supposition be correct, the present reference of the almost exactly intermediate males, from eastern Missouri, will stand; otherwise, it may not. Additional intergrades with noveboracensis are available from eastern Iowa. Of five specimens from Hillsboro, Iowa, two males and a female have tympanic bullae like those of primulina but the other two males have bullae like those of noveboracensis. The female is smaller than primulina and in this small size and in general configuration of the skull, viewed dorsally, is more nearly like noveboracensis. As a whole, the population averages almost exactly intermediate. The same is true of 3 males and one female from Muscatine. The subadult male from Keosaqua, to my eye, resembles noveboracensis in the greater length of the skull anteriorly to the postorbital processes, and in the relative narrowness across the mastoidal region, but otherwise is more like that of primulina. Two males and one female from Tipton, although in each instance variously intermediate, are as a whole nearer primulina, No. 2865, Coe College, male adult, from Cedar Rapids, has characters of the three races, spadix, noveboracensis and primulina. In the skull, the width suggests spadix, the narrow mastoid region, noveboracensis, and the tympanic bullae are as in spadix or primulina. One male, no. 12, Coe College, from Dubuque, is as narrow across the mastoid region as is noveboracensis although the bullae are well inflated as in primulina. The skull, without corresponding skin, of a female, no. 140a, Iowa State College, from Green's Island, also resembles noveboracensis in narrowness of the mastoidal region, and in small size of skull, but in larger teeth, broader tympanic bullae, and sagittal crest is referable to primulina. Of two females from Vinton, one adult is typical of primulina but the other, a subadult, is practically indistinguishable from female noveboracensis, from Ann Arbor, Michigan. Three males from Vinton agree well with primulina except that the interorbital region is wider than average and thereby suggests spadix or noveboracensis. An adult female from New Hartford also is typical of primulina except for the broader interorbital region. Three males from Fayette are typical of primulina. Other specimens from Iowa are intergrades with spadix, or if not with spadix, with the animal of northwestern Iowa which in some ways combines the characters of longicauda and spadix. For example, no. 2665, Coe College, an adult male from Davenport, has the anterior part of the skull (all that is preserved) heavily ridged as in spadix and in addition, the underparts are marked with the shade of reddish displayed by topotypes of spadix and with some yellowish as seen in longicauda. The color pattern, however, is as in primulina. A young male, no. C-51, Iowa State College, from Kelley, Story County, has anteriorly truncate bullae as are more frequently found in the longicauda-spadix stock of northwestern Iowa, than in primulina. In other respects, the animal, in so far as can be judged from the broken skull, agrees with primulina as it certainly does in color, color pattern, and external measurements. An adult male, no. 499a, Iowa State College, from 2 miles east of Ledges St. Park, in Boone County, in short body, size of teeth, and size of skull, in so far as the broken parts can be measured, resembles primulina more closely than it does any other subspecies. The long tail, long hind foot, wide extent of the light-colored underparts, and extension of the color of the underparts onto the hind feet are more as in spadix. Other intergrades with spadix from Iowa are mentioned in the account of spadix. The specimen from Swartz, Louisiana, suggests intergradation with arthuri in that the anteromedial part of the tympanic bulla is less inflated than in typical primulina. Intergrades with longicauda are available from Riley and Pratt counties, Kansas. No. 7182, Univ. Kans., subadult male in winter pelage, from near Winkler, has a skull of larger size as in longicauda with which race it seems to agree in large size of body, tail and hind foot, although the collector's measurements are lacking. Color pattern and relative proportions of the skull throughout are as in primulina. The young male, no. 3495, Univ. Kans., from Pratt, Kansas, agrees in external measurements and large size of skull with longicauda, but has the color and color pattern precisely as in primulina. The teeth are smaller as in primulina. Immaturity prevents judging of its relationships on the basis of relative proportions of the skull. The two specimens, skins only, available from Oklahoma, are provisionally referred to primulina. These are remarkable for the restriction of the color of the underparts and for the intensity of the yellow coloration of the underparts. The specimen from Norman has the color of the underparts entirely absent from the hind legs and not extending posteriorly to the penis. On the chest and lower throat, large spots of color of the upper parts are present and the yellow area of the underparts on the belly is narrower than in any other specimen of primulina examined. The specimen from 8 miles northwest of Stillwater has the color of the underparts only a little less restricted although this color does extend over the inguinal region almost to the knees. The skin of the posterior part of the body of a weasel is available from 10 miles south of Sulphur Springs, Texas. It, likewise, is only provisionally referred to primulina. The coloration is about as in the specimens from Oklahoma but the distribution of the color of the underparts cannot be made out. The dark color of the upper parts occurs far westward in animals which otherwise display characters of longicauda. Among these intergrades, the larger size of longicauda generally is combined with this dark color. This geographic behavior of the dark color of the upper parts is analogous to the condition described in M. f. spadix. Stated in another way, the dark color of the upper parts is the character, of the eastern animal, last to disappear as one goes westward across the Mississippi Valley toward the range of longicauda which is a subspecies of markedly different size, shape of skull, and coloration. Only two of 29 specimens from Kansas show infestation of the frontal sinuses. All four of the specimens from Missouri have the frontal sinuses malformed as do 9 of the 14 from Arkansas examined in this respect. An adult female from Boone County, Iowa, bears the date May 9, 1938, and the annotation by T. G. Scott, "Fox-killed."
Mustela frenata arthuri HallLong-tailed Weasel
Compared with the skull of M. f. olivacea that of arthuri differs as follows: Averaging smaller in every part measured; basilar length 5 mm. less; by weight a fourth lighter; relative to basilar length, interorbital breadth greater and zygomatic and especially mastoid breadth less; dorsal outline of skull more convex in longitudinal axis; tympanic bullae narrower and less inflated especially on anteromedial faces. Compared with the skull of noveboracensis that of arthuri has the zygomatic breadth equal to or exceeding the distance from the anterior palatine foramen to the anterior margin of the tympanic bulla, whereas the zygomatic breadth is less than this distance in noveboracensis. Also, in arthuri, the rostrum is relatively shorter, the braincase is more inflated anteriorly, the zygomatic arches are more uniformly spreading, and the dorsal outline of the skull is distinctly convex, both transversely and longitudinally, whereas it is transversely more nearly flat in noveboracensis and longitudinally is concave in the interorbital region. Compared with M. f. primulina, arthuri has narrower bullae, which are much less inflated on their anteromedial faces, a less marked postorbital constriction, a braincase which is narrower across the mastoid region and broader anteriorly, and a skull, which, in longitudinal axis, has the dorsal outline markedly more convex. Compared with the skull of M. f. texensis that of arthuri is smaller in every part measured; length one-fifth less; one-half as heavy; postorbital constriction less marked; braincase relatively narrower posteriorly and tympanic bullae less inflated especially anteromedially. Compared with the skull of M. f. frenata that of arthuri is smaller in every part measured; basilar length 6 mm. less; a third lighter; postorbital constriction less marked; relative to the basilar length the rostrum is broader, longer and deeper; the zygomatic expanse and breadth of the braincase across the mastoids is less; the dorsal profile of the skull is more convex in longitudinal axis; zygomata evenly spreading rather than abruptly protruding from skull posteriorly; tympanic bullae less inflated anteromedially. Remarks.—In 1926, Stanley C. Arthur, then Director of the Division of Wild Life, for the Louisiana State Department of Conservation, obtained specimens of this weasel. Some of them were mounted and the remainder were placed in the collections of the United States National Museum and the Museum of Vertebrate ZoÖlogy. In 1938 to 1940 George H. Lowery saved specimens from Baton Rouge, which showed the color of the summer pelage and revealed that the size of males was more than was indicated by the original materials. In 1940 and 1941 Rollin H. Baker obtained specimens from eastern Texas which greatly extended the known geographic range. In addition to the localities represented by specimens examined, Arthur (1928:117) has recorded specimens from Greensburg, St. Helena Parish; Braithwaite, Plaquemines Parish; Geismar, Assumption Parish; Laurel Hill, West Feliciana Parish; French Settlement, Livingston Parish; and Kentwood, Tangipahoa Parish. All these localities lie within the eastern half of southern Louisiana. A skin-only, no. 38902, Mus. Vert. ZoÖl., obtained from a fur buyer by Stanley C. Arthur, was taken in Mississippi "south of Jackson." Possibly it is of the subspecies arthuri. Intergradation with M. f. olivacea is indicated by a specimen from Mobile County, Alabama, commented on in the account of olivacea. Intergradation with primulina is indicated by the shape of the anteromedial part of the bullae of the specimen from Swartz, Louisiana, that is referred to primulina. The lack of specimens from the northern two-thirds of Mississippi and from western Tennessee, prevents any definite statement as to the limits of range of arthuri in those areas. In comparison with animals from the type locality, the slightly larger size of the adult male from Baton Rouge, and the still larger size of the adult male of primulina from Swartz, Louisiana, suggests that the olivacea "influence" may extend farther west in the latitude of northern Louisiana than anywhere else. None of the skulls examined shows malformation of the frontal sinuses such as results from infestation by parasites in some races. Arthur (1928:115) speaks of the "... cut-over swamp land, where the tupelo and cypress have been removed, ..." as constituting suitable habitat for this animal.
Mustela frenata olivacea HowellLong-tailed Weasel Plates 16, 17, 18, 31, 32 and 33
The length of the hind foot averages less than the basal length in both males and females. The tail averages 52 per cent as long as the head and body in males and 51 per cent in females. Average differences in measurements of the two sexes are: Total length, 49; length of tail, 19; length of hind foot, 5. An adult male, no. 41023, and an adult female, no. 41024, each taken in February, 1929, on the Sinkola Plantation, Thomas County, Georgia, weighed 15 ounces (425 grams) and 7 ounces (198 grams) respectively according to Charles O. Handley. Externals.—As described in Mustela frenata noveboracensis, except that hairiness of foot-soles slightly less than shown in figure 19. Color.—Upper parts, in summer, near tone 4 of Burnt Umber of OberthÜr and Dauthenay, pl. 304. In winter lighter, between tones 3 and 4 of Raw Umber of OberthÜr and Dauthenay, pl. 301. Dark spot at each angle of mouth present or absent. Underparts ranging from Massicot Yellow to Cream Buff except on chin and upper lips which are white. Tip of tail black. Upper parts of uniform color. Color of underparts extends distally on posterior sides of forelegs over antipalmar faces of toes and on medial sides of hind limbs to ankles. Least width of color of underparts averaging, in a series of five males from Talbot Co., Georgia, 29 (extremes 24-34) per cent of greatest width of color of upper parts. Black tip of tail in same series, averaging 65 (extremes 60-70) mm. long, thus longer than hind foot and averaging 43 per cent of length of tail-vertebrae. The spot at the angle of the mouth is absent in one-third of the specimens examined. The upper lips are white in specimens from the southern part of the range of olivacea but in the northern part of the range of the subspecies the upper lips are dark colored as in noveboracensis. Skull and teeth.—Male (based on 5 adults from Talbot Co., Georgia): See measurements and plates 16-18; weight, 5.3 (5.0-6.4) grams; basilar length, 48.3 (45.8-50.1); zygomatic breadth more or less (usually less) than distance between condylar foramen and M1 and more or less (usually more) than distance between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth more or less than (averaging about equal to) postpalatal length; postorbital breadth less than length of upper premolars and more or less than (about equal to) width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth more or less than (about equal to) distance between foramen opticum and anterior margin of tympanic bulla; breadth of rostrum less than length of tympanic bulla; least width of palate less than greatest length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 3 to 5 upper incisors; height of tympanic bulla not less than distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer than rostrum (one exception); anterior margin of masseteric fossa below posterior half of m2. Female (based on 2 adults from Thomas Co., Ga., and one from Talbot Co., Ga.): See measurements and plates 31-33; weight, 3.8 (3.5-4.0) grams; basilar length, 43.4 (42.7-44.0); zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth less than length of upper premolars and more or less (usually more) than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate less than greatest length of P4; tympanic bulla as far posterior to foramen ovale as width of 3 to 4 (including I3) upper incisors; height of tympanic bulla not less (usually more) than distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer than rostrum. The skull of the female averages 28 per cent lighter than that of the male. Compared with the skull of M. f. peninsulae, of which only one good skull, and that a female, is available, that of M. f. olivacea averages smaller and has relatively and actually smaller and less inflated bullae. As compared with the skull of M. f. noveboracensis, that of olivacea in the case of males is larger in every part measured and relative to the basilar length is broader across the zygomatic arches and mastoids. However, the rostrum and interorbital region are relatively narrower. The orbitonasal length is relatively less. The tympanic bullae are broader and more inflated. The same differences hold as between females of noveboracensis and olivacea. Indeed, the females of these two races differ more than do the males. Additional, selected differential cranial characters in the females are, in olivacea, as follows: Weight averaging 3.8 grams rather than 1.7 grams; braincase with, rather than without, sagittal crest; anterior border of tympanic bulla separated from foramen ovale by breadth of less than, rather than breadth of more than, 4 upper incisors (including I3); height of tympanic bulla not less than, rather than less than, distance from its anterior margin to foramen ovale; squamosal bone, between anterior margin of tympanic bulla and foramen ovale, ventrally concave rather than ventrally convex. Comparisons of the skulls with those of M. f. arthuri and M. f. primulina are made in the accounts of those subspecies. Remarks.—Excepting two young specimens from South Carolina in the Charleston Museum, no specimens of this race of large weasel seem to have been preserved until Arthur H. Howell, in the course of his study of the mammals of Alabama, procured specimens on which his name, olivacea, was based. Later, Francis Harper obtained three instructive specimens from Okefinokee Swamp. Really adequate material, for the localities represented, owes its preservation to the alertness of Charles O. Handley, when he resided at Thomasville, Georgia, and to Hallie E. Fuller of Geneva, Talbot Co., Georgia. The distinctness of M. f. olivacea from M. f. peninsulae is not satisfactorily established due to inadequate material of peninsulae. Differences shown by the specimens seen indicate that, as compared with olivacea, peninsulae is larger, has transversely wider light-colored underparts which possess more yellow, and a larger skull with more inflated tympanic bullae. In each of these characters, olivacea is intermediate between noveboracensis on the north and peninsulae on the south. The question arises, therefore, whether the animals here recognized under the name olivacea really constitute a recognizable subspecies or instead are only representatives of a subspecies which reaches its extreme development in Florida. In the latter event, the name peninsulae would apply to all. Examination of more material from Florida, especially from the southern half of Florida, will be necessary to answer this question. This large weasel of the southeastern United States is remarkably different from noveboracensis. Indeed, were it not for actual intergrades such as the two from Fort Payne, Alabama, and York, South Carolina, which are described in the account of M. f. noveboracensis, and the six specimens from northwestern Alabama, which are referred to olivacea, the systematist, I believe, would have little or no hesitancy in designating the two as distinct species, especially on the basis of differences to be seen in the skull. Not only are the two forms structurally more different than usually is the case but between two geographically, adjacent subspecies of the same species of mammal, but the belt where intergradation occurs appears to be narrow. Nevertheless, when material of the two races is laid out in geographic order, and examined in mass, certain features are seen to undergo gradual change as a person's eye travels from specimens from, say, the center of the range of noveboracensis to specimens from southern localities adjoining the territory occupied by olivacea. One of these features subject to gradual change is the color of the underparts. Beginning at the Adirondacks of New York where a large number of the specimens have white underparts, the underparts become more intensely yellowish southward through the range of noveboracensis into that of olivacea. Indeed, this progressive trend seems to continue right on southward through the range of olivacea into that of peninsulae. Turning in the opposite direction we find that the least width of the underparts decreases gradually northward toward the range of noveboracensis. There is, likewise, a decrease to the northward in length of the skull and relative, as well as actual, narrowing of the braincase and tympanic bullae. However, in least width of color of underparts and the mentioned cranial features, the trend stops relatively abruptly at the southern boundary of the geographic range of noveboracensis and does not continue on, northward, into the range of noveboracensis as is the case with the change in intensity of yellowness of the underparts. Two males, in the United States National Museum, Biological Surveys Collection, from near Leighton, Alabama, no. 178386 from the Tennessee River nine miles north [of Leighton?] and no. 180240 from La Grange Mountain, although clearly referable to olivacea on the basis of cranial characters, show some approach to noveboracensis in lesser size of the skull and agree with noveboracensis in the narrowness of the color of the underparts. Also, these specimens, like others from the northern part of the range of olivacea, for instance, no 31.227, Charleston Museum, from Mayesville, South Carolina, have the color of the underparts extended only part way out on the hind limb toward the foot. In specimens of olivacea from the southern part of its range the color of the underparts is extended onto the hind feet and this trend reaches its extreme in peninsulae, specimens of which have the feet and larger parts of the limbs marked with the light color of the underparts. An adult female, no. 32.32, Charleston Museum, although typical of olivacea in most respects, is nevertheless an intergrade. The teeth are as small as in some specimens of noveboracensis. The size of the skull is only slightly nearer that of olivacea than it is to that of noveboracensis. The proportions of the skull, however, are distinctly those of olivacea. Five other specimens, from northwestern Alabama, namely two from eight miles north of Nauvoo, two from Shoal Creek, and one from White Creek, also show intergradation between noveboracensis and olivacea. The remarks concerning color and color pattern of the specimens from Leighton apply equally well to the five from northwestern Alabama. In cranial characters, no. 51658 from Shoal Creek is referable to olivacea, as also is no. 51677 from the same place, providing it is a female rather than a male as sexed by the collector. No. 57146 from White Creek also is referable to olivacea although the skull shows some approach to that of noveboracensis. Of the two males from near Nauvoo, no. 51652 is to me indistinguishable from noveboracensis, but no. 51653 does have some characters of olivacea, although on the whole, the latter, too, seems to be a little nearer noveboracensis than olivacea. However, because the mean of these seven specimens from northwestern Alabama is nearer olivacea than noveboracensis the former name may be applied. Another specimen from "Souinlonie" Creek, Clark County, Mississippi, has the coloration and rostral configuration of primulina, narrow mastoidal breadth and smaller teeth of noveboracensis and skull of large size with "full" braincase as in olivacea. No. 235364, U. S. Nat. Mus., from the Mobile River at the "L. and N. RR. Crossing," Mobile County, Alabama, although definitely olivacea, shows approach to arthuri in that the dorsal outline of the skull is longitudinally more convex and the tympanic bullae are less inflated than in olivacea and in that the color of the underparts is almost exactly as in the type specimen of arthuri. The young specimen labeled as from "Silver Springs," Florida, has large tympanic bullae (17 mm. long) and several characters that show its relationship to peninsulae as that race is now understood. Because the sex is unknown the identification as olivacea is tentative and is made on the assumption that the specimen is a male. If it is instead a female, the animal is referable to peninsulae. An adult, female specimen in the Charleston Museum, no. 27.239.1, taken at St. Matthews, South Carolina, on December 8, 1927, contained four embryos which averaged 19 mm. in length and 47.75 centigrams in weight. Another adult female, in the Charleston Museum, no. 32.32, taken on February 21, 1932, at the same place, has prominent mammae, and the collector has noted that two were slightly active. Sixteen of twenty-nine adults examined show infestation of the frontal sinuses by parasites. However, in none is the malformation of the frontal region so great as frequently occurs in M. f. noveboracensis.
Mustela frenata peninsulae (Rhoads)Long-tailed Weasel
In comparison with M. f. olivacea, the insufficient material of M. f. peninsulae suggests that its skull averages larger and has relatively as well as actually larger and more inflated tympanic bullae. Remarks.—The first published mention of this weasel seems to have been the original description which appeared in 1894. This description was based on a single specimen sent to Samuel N. Rhoads by W. S. Dickinson, who, in the following year, procured another specimen at Tarpon Springs. So far as known only eight other specimens, as listed under "Specimens examined," have found their way into collections of study specimens. H. H. Bailey (1930:1) credits the range of this subspecies as extending south "to the shores of Florida Bay and the Gulf of Mexico, where ever high ground occurs." Evidence of intergradation between M. f. peninsulae and M. f. olivacea is provided by specimens of olivacea from Gainesville, Florida, and the Okefinokee Swamp, Georgia. These specimens, on the average, have the color of the underparts wider, the skull larger, and the tympanic bullae relatively larger than do specimens of olivacea from farther north. In these features, approach to M. f. peninsulae is shown. Light facial markings occur in this subspecies. They are similar to those possessed by weasels which occur at the same latitude and under corresponding climatic conditions on the Pacific Coast. The type specimen and one from Tarpon Springs have white facial markings. Two of the three specimens from Apopka also show white facial markings, although in reduced amount. One of the four specimens of M. f. olivacea from Gainesville, Florida, has well-developed light (white) facial markings. Also of the four specimens of M. f. olivacea examined from Okefinokee Swamp, Georgia, one has prominent white facial markings. However, in it the pattern is so unusual as to suggest that it is an instance of partial albinism rather than an outcropping of a racial tendency, or a pattern of coloration induced by climatic factors. None of the eight available skulls show any infestation of the frontal sinuses by parasites.
Mustela frenata spadix (Bangs)Long-tailed Weasel Plates 16, 17, 18, 31, 32 and 33
Skulls of adult males of spadix from Elk River, Minnesota, as compared with those of longicauda from Alberta, are larger in every part measured. Relative to the basilar length these skulls of spadix are broader across the mastoid region, narrower across the zygomata, deeper through the plane of the postorbital processes, shallower through the braincase and have relatively shorter tympanic bullae. Whereas the tympanic bullae of longicauda are, on the average, approximately as long as the rostrum (orbitonasal length), in spadix the rostrum is longer than the bulla. Viewed posteriorly, the braincase of spadix is seen to be much shallower and wider than that of longicauda. Indeed, the depth of the braincase, measured at the anterior end of the basioccipital, amounts to only 56 per cent of the mastoid breadth in spadix as against 61 per cent in longicauda. The longer, waistlike, postorbital constriction, relatively smaller braincase, and especially the relatively narrower zygomatic expanse in spadix imparts to its skull a more slender appearance than has the skull of longicauda. These differences are not shown by the skulls of females. To be sure, spadix, in most of its cranial measurements, averages slightly larger, has a relatively shallower braincase and is relatively deeper through the postorbital processes, but these differences are so slight that inclusion of one more specimen, of slightly different proportions, in the average might cause the average measurements to read as they do in longicauda. Compared with noveboracensis, from Massachusetts, adult skulls of spadix, taking sex into account, are larger in every part measured and are relatively as well as actually wider and deeper throughout. Also, in spadix: Sagittal and lambdoidal crests higher, especially in females; anterior margin of tympanic bulla projecting up sharply from squamosal; occiput more flattened in posterior view; tooth-rows relatively and actually longer but orbitonasal length relatively shorter; postorbital processes more robust; zygomatic arches widely bowed outward rather than evenly rounded; canines larger; squamosal less swollen ventrally, especially in females. Between noveboracensis and spadix, the differential cranial characters are greater in number and degree between females than between males. Comparison of the skull with that of M. f. primulina is made in discussion of that subspecies. Remarks.—Edgar A. Mearns in 1889 and the early nineties took several specimens of this weasel and it was principally on these that Bangs in 1896 (p. 8) based his description. The best material, however, is that from Elk River, Minnesota, collected in later years by Bernard Bailey, and supplemented by one specimen taken in 1885 by Vernon Bailey and another by his sister Anna Bailey in 1891 at the same place. Mustela frenata spadix has just one structural feature of a "unique" kind which serves to differentiate it from the geographically adjoining subspecies. This feature is large size. The other diagnostic characters ascribed to spadix are of an intermediate sort—intermediate as between two extremes, one found to the westward in longicauda and the other to the eastward in noveboracensis. For example, the dark-colored upper parts are merely darker than in longicauda and merely lighter than in noveboracensis. The color is not "different"; it is only "intermediate." Furthermore, each of the characters ascribed to spadix, including large size itself, undergoes change from one part of its geographic range to another; the characters are not constant over a wide area. Indeed, excepting the large size which remains relatively uniform over the northern two-thirds of the range, no two localities have been found from which the specimens can be said really to agree in characters. By way of illustration, the coloration of the upper parts may be cited. Near the range of noveboracensis the average coloration of individuals from one locality is only a little lighter than in noveboracensis. Farther westward the average coloration is a little lighter and farther westward yet, toward the range of the extremely light colored longicauda, the average coloration is lighter still. Although all these animals are darker than longicauda and lighter than noveboracensis, those from the three places do not agree among themselves. Because of the lack of more than one character of a "unique" kind and because of the inconstancy, geographically, of other characters, and for that matter, lack of constancy geographically in combination of characters, the writer regards spadix as a barely recognizable subspecies. Examination of the specimens of spadix shows that the individual variation in a single species is greater in a region of intergradation than it is some distance inside the borders of the geographic range of a well-marked subspecies. This is illustrated by three specimens of M. f. spadix in fresh summer pelage from the single locality, Elk River, Minnesota. In these, the color of the upper parts varies from a little darker than Cinnamon Brown to Vandyke Brown. At any one locality well within the range of longicauda, or noveboracensis, there is nowhere nearly so much variation in color, even in much larger series of specimens. Study of the specimens here assigned to spadix reveals that some features regarded as of diagnostic value for one or the other of the two races, longicauda and noveboracensis, behave differently. For example, the dark coloration of the upper parts, which is characteristic of noveboracensis, manifests itself far westward within the range of spadix whereas the wider extent of the light-colored underparts, which is characteristic of longicauda, and the Olive Ocher, rather than Pale Orange Yellow, color of these underparts, are seen in varying degree all the way across the range of spadix. Thus, these animals are colored above like noveboracensis and below like longicauda, but not vice versa. In these animals, then, the longicauda type of underparts is dominant, in one sense of the word, over the noveboracensis type of underparts, and the noveboracensis type of upper parts is dominant over the longicauda type of upper parts. Each of these features is subject to actual intergradation and does not always behave as a "unit character," that is to say, one which is either present or absent. However, the noveboracensis type of upper parts is carried much farther west before being diluted than is the noveboracensis type of underparts. Indeed, within the range of noveboracensis itself, the broad extent of the longicauda type of underparts is manifest. This is, of course, near the western margin of the range of noveboracensis. The large size of males of spadix, as exemplified by specimens from Elk River (see measurements on page 421), seems to be retained across the northern part of the range here assigned to the subspecies. This larger size than is found in longicauda from Alberta, is shown also by some specimens from eastern North Dakota which are assigned to longicauda. However, the average of these Dakotan specimens, all characters considered, is nearer to my concept of longicauda. Inspection of the cranial measurements of spadix shows also that in addition to its large size it is distinguishable from any one of the geographically adjoining races by its relatively (to basilar length) greater, as well as actually greater, mastoidal breadth. This might be included with size as a unique character distinguishing spadix from longicauda and noveboracensis. However, it is not clear whether or not this greater mastoidal breadth is more than a function of the large size. Excepting the greater mastoidal breadth and generally larger size of the skull, the cranial features distinguishing males of spadix from longicauda are features in which spadix shows approach to noveboracensis. This is true, in spadix, of the relatively longer (in comparison with longicauda) rostrum, relatively lesser zygomatic breadth, relatively shallower braincase measured at the anterior end of the basioccipital, and relatively deeper skull as measured at the posterior borders of the last upper molars. This same approach to noveboracensis already has been pointed out with respect to color of the upper parts and is evident also in the relative shortness of the tail which averages only 51 per cent of the length of the head and body rather than 55 per cent as in longicauda. Because the longicauda type of animal previously has been regarded as specifically distinct from the noveboracensis type of animal, comment is offered below on selected specimens, referred to spadix, which are regarded as intergrades with noveboracensis or with other subspecies. No. 8722, Univ. Wisconsin, adult male, in the white winter coat, from north central Itasca County, Minnesota, obviously has characters of M. f. spadix or longicauda that occur to the west and M. f. noveboracensis of the east. Selected outstanding characters of longicauda are its long tail, anteriorly truncate tympanic bullae and large teeth. Characters indicating its affinities with noveboracensis are smaller size of skull, general narrowness of skull, and relatively low tympanic bullae. The skull is intermediate as regards several individual structural features. For example, although long and narrow and in this feature more nearly approaching noveboracensis, the skull is wider than usual in that subspecies and thus approaches that of longicauda or spadix. The hind foot, in the dried state, measures 47 millimeters. This large hind foot, obviously long tail (the specimen lacks external measurements), and anteriorly truncate bullae constitute basis for here referring the specimen to spadix. However, the seemingly small size of the body and the narrow skull clearly show relationship to noveboracensis. Specimens, referred to spadix, from northern Iowa, are instructive as showing what happens where the ranges of noveboracensis, primulina, spadix, and perhaps longicauda, meet. No. 47167, Univ. Mich. Mus. ZoÖl., a nearly adult female, taken on November 22, 1915, at Island, Clay County, and in process of assuming a brown winter pelage, retains enough of the dark summer pelage to show that the color was slightly lighter than average for spadix. The color pattern, white lips, and extension of light color of the underparts onto the feet, agrees with spadix or longicauda as does also the long tooth-row. The overall length of the skull is intermediate between that of spadix and primulina. The proportions of the anterior part of the skull and of the tympanic bullae resemble those found in primulina. A subadult male skull only, no. 123846, American Museum of Natural History, from Webb, Clay County, shows approach to primulina in the narrowness of the rostrum. A young male from Ruthven, Iowa, no. 48340, Univ. Michigan, has a large skull approaching in size that of spadix, has the longicauda-spadix type of light-colored underparts and color pattern, and is slightly darker above than true longicauda. Another subadult male in the white winter coat from Palo Alto County, no. 35756, Univ. Michigan, has a large skull, which shows approach to primulina in its narrowness anteriorly and in some other features. Although the tail is of moderate length, the body is large as in spadix or longicauda, and the length of the hind foot suggests spadix or longicauda. A subadult male, no. 425a, Iowa State College, from Manson, Iowa, in brown winter pelage, agrees with primulina in the restriction of the area of the light color of the underparts and in less expanded zygomatic arches. The teeth are intermediate in size between those of noveboracensis and primulina on the one hand and those of spadix and longicauda on the other. In other respects it agrees with, or is more nearly like, spadix. An adult female, no. 426a, Iowa State College, from Barnum, in the brown winter coat, agrees with primulina except that the orbitonasal length of the skull is more as in spadix and the presence of some light color on the lower part of the hind legs suggests spadix. The skull only, no. 440a, Iowa State College, labeled merely Webster County, Iowa, is almost a duplicate of no. 426a. A subadult male, no. 427a, Iowa State College, from Moorland, Iowa, only about six miles southeast of Barnum, likewise is indistinguishable from primulina except for having a white winter coat and in being relatively broad in the mastoidal region. Nevertheless, both of these animals are here referred to spadix because the average of specimens from this general area is nearer that of spadix. No. 497a, Iowa State College, an adult female in white winter pelage, from Ames, approaches primulina in the narrow rostrum and smaller teeth but otherwise approaches or even agrees with spadix. Two adult males, without external measurements, from Pilot Mound, Iowa, have skulls quite like males of longicauda from Alberta. The only approach noted to eastern forms is the restricted color of the underparts on no. 2856, Coe College, which has a brown winter coat. The color of the underparts is not extended so far out on the feet as in longicauda. Also the tympanic bullae of this specimen are a trifle narrower. The other male, no. 2652, is in the white winter coat. The one female from the same place, no. 2660, Coe College, in brown winter pelage, has a skull notably unlike that of longicauda or spadix; the skull is narrower and practically indistinguishable from that of the largest female skull of primulina available from Lawrence, Kansas, save that the tooth-row is much longer. The color pattern also agrees with that of primulina or noveboracensis in that the color of the underparts extends only as far as the knee on the hind legs and is narrow on the belly. Nevertheless, another adult female, no. 120a from Amaqua Township, some 6 miles southwest of Pilot Mound, is in all respects typical of spadix. This is the more remarkable because another comparable specimen from less than 20 miles to the southwest in Worth Township is equally typical of primulina. Two young females from Chester, Iowa, nos. 2656 and 2874/2873, Coe College, have skulls larger than those of corresponding age of primulina or noveboracensis. The color is as in spadix. The color pattern of the underparts also is as in spadix or longicauda except that the width of the area of light color on the belly is restricted somewhat although not so much as in noveboracensis or primulina. Of four males from the same place, also in the collection of Coe College, no. A2874 is a white skin only and does not provide diagnostic characters. The three other males, each in summer pelage, are marked and colored as are the two females from the same place except that male no. 2861 has the color of the underparts so much attenuated on the hind legs that it barely, uninterruptedly, extends to the feet. No. 2658 is young, or perhaps barely subadult. The skull is large and referable to spadix. The two adults, nos. 2861 and 2657, differ cranially from typical (Elk River, Minn.) spadix only in being slightly narrower across the mastoids and in having the bullae a little narrower. In these departures they show some approach to primulina and to noveboracensis. Another male, subadult, no. 2867, Coe College, from Decorah, which has acquired half of the white winter coat, agrees with the males from Chester except that the preorbital part of the skull is shortened much as in some specimens of primulina. From Lansing, in extreme northeastern Iowa, a large subadult male, no. 2864, Coe College, of 453 mm. in total length and half through with acquiring the white winter coat, agrees with the males previously described from Chester except in having the palate narrower as in noveboracensis. The adult female available from Lansing, no. 2863/2862, Coe College, in white winter pelage except for the top of the head, although a large skin, has a skull smaller than that of any spadix or longicauda and of about the same size as that of no. 3838, Univ. Kansas Mus. Nat. Hist., of primulina, from Lawrence, Kansas, except that the skull of no. 2863/2862 is much narrower across the mastoids. This specimen, then, shows approach to noveboracensis in narrowness of the mastoidal region, to primulina in other respects and to spadix. Many of these instructive specimens from Iowa, made available to the present writer by Mr. W. F. Kubichek, were brought together at the Coe College Museum by the late B. H. Bailey. Most of them were obtained from trappers who did not supply the conventional external measurements taken in the flesh. Even though these are lacking, the specimens clearly show that actual intergradation occurs where the ranges of M. f. longicauda, spadix, noveboracensis and primulina meet. The dark color of the upper parts, restriction of the color of the underparts on the ankles with the result that the color reaches the toes in interrupted fashion, and large skull, of no. 18912 of the Museum of the University of South Dakota, from Roberts County, South Dakota, clearly place this specimen with spadix, rather than with longicauda. Likewise, male, subadult, no. 11376, Univ. South Dakota, from Clay County, South Dakota, is referable to spadix. Although without external measurements, the specimen obviously is large. The patch of summer pelage on its head and neck is darker than the summer pelage of longicauda, and the orbitonasal length is greater than the length of the tympanic bullae; all these features are characters of spadix. The adult male from Fort Sisseton, South Dakota, no. 188407, United States National Museum, figured by Merriam (1896, p. 20, figs. 7-9), is almost exactly intermediate between longicauda and spadix, although here referred to the latter. Five specimens, nos. 147375, 147432, 147762, 148720 and 148721, U. S. Nat. Mus., including 3 skulls only from Beemer, Cuming County, Nebraska, are intergrades between M. f. longicauda, M. f. primulina and M. f. spadix. One skin is in white winter pelage and the other, a female, is in summer pelage which in coloration and color pattern agrees with that of spadix. External measurements of the male agree with those of longicauda. Measurements of the female agree with those of spadix except that the tail is shorter as in primulina. The skulls are as long as in longicauda but are more slender than in either longicauda or spadix although nearer the latter in this respect. In dorsal aspect, the skulls especially posteriorly to the orbital region, resemble primulina. All points considered, the animals seem best referred to spadix. Although the degree of development of certain morphological features has been settled upon as indicative of the race spadix, some doubt remains as to where the western boundary of its range should be shown. This results from the fact that color has been taken into account as one diagnostic feature and this feature is lacking in the white winter specimens which, from the following places, are all that are available: Kittson County, Minnesota; Moorhead, Minnesota; Casselton and Valley City in North Dakota; Armour, South Dakota and Clay County, South Dakota. In summary, more specimens in the summer coat will be required to establish definitely the boundary between the ranges of longicauda and spadix. Surber (1932:49) has referred to additional specimens of this weasel in the University of Minnesota Museum as from Winona, Hennepin and Isanti counties of that state. At Elk River, Minnesota, B. Bailey (1929:156) found this species to be about half as abundant as Mustela cicognanii and that it is "more often found in the open timber and about the dry ridges and fields." Of seventeen adult or subadult skulls of this race from Minnesota, ten have obvious marks of infestation of the frontal sinuses. In no skull, however, has the infestation resulted in so much malformation, as occurs in noveboracensis.
Mustela frenata longicauda BonaparteLong-tailed Weasel Plates 16, 17, 18, 31, 32 and 33
Remarks.—Richardson's (1829:47) account on which Bonaparte may be said to have based his name, records measurements in inches and lines which I transpose into millimeters as follows: Total length, 440 mm.; length of head and body, 305; length of tail (vertebrae), 135; length of tail (including fur), 164 mm. Specimen no. 43.3.3.3 in the British Museum, which has by some persons been regarded as the type, yields measurements as follows: Total length, 408 (which allows for 15 mm. loss of the fleshy part of the end of the tail); length of head and body, 272; length of tail (vertebrae), 136 (= 121 + 15); length of tail (including fur), 162 (142 + 20 mm. that appears to have been lost). Richardson's specimen would appear to have been of unusual proportions and to have been larger than no. 43.3.3.3. Some reasons for and reasons against regarding this specimen as the holotype are given in the account of M. erminea cicognanii. The name longicauda was applied to practically all long-tailed weasels of the western United States at one time but as one after another of the geographic variants in the mountainous regions were designated as separable, the name longicauda came to be restricted to the light-colored, relatively large, animal of the Great Plains. The intergradation of longicauda with spadix and oribasus has been commented on in the discussions of those subspecies. The larger size and darker color of specimens referred to longicauda from Devils Lake and Grafton, North Dakota, are features indicative of intergradation there with spadix. Two young females from Waterton Lake Park, Alberta, by their darker than average color, suggest intergradation with oribasus, as, for that matter, does the specimen from Waterton Lake [= Chief Mountain Lake, in Montana] itself, which, however, is even darker than the two specimens taken on the Canadian side of the line and hence is referred to oribasus. An adult female, no. 175586, U. S. Nat. Mus., from Moose Pass, Alberta, examined after the above was written, is larger than any other female seen of longicauda and in this respect may show approach to oribasus, which in the northern part of its range is of large size as judged by males from the Bowron Lake region. One male, no. 8564, Nat. Mus. Canada, from Max Lake, Turtle Mountain, Manitoba, presents puzzling characters. The external measurements of 465, 170, and 57, are in keeping with the great length of the skull which has a basilar length of 48.8. The tooth-rows are 19.3 in length and the mastoid breadth, 25.4. The relative narrowness indicated by the mastoid breadth is maintained throughout the skull. The only other specimens relating to the Turtle Mountains that have been seen are two male, skins without measurements or corresponding skulls, nos. 38902 and 38903, Amer. Mus. Nat. Hist., labeled as from either "Stump Lake or Turtle Mts.," North Dakota. One of these, no. 38902, is much darker than the other. Possibly it is from the Turtle Mountains and the other, lighter-colored one, is from Stump Lake. Study of additional specimens from the Turtle Mountains might show the existence there of a distinct race. Four specimens, in the collection of Myron Swenk, from Inland, Clay County, Nebraska, are instructive as showing how intergradation occurs between primulina and longicauda. A subadult male, no. 10, is intermediate in external measurements and in color but in each instance is nearer primulina. The same is true of the least width of the color of the underparts. The color of the underparts extends uninterruptedly over the hind legs to the toes as in longicauda, but is absent from the underside of the tail as in primulina. In the skull, the basilar length, breadth of bulla, and size of teeth are nearer longicauda, as are also the ratios to the basilar length of the length of tooth-rows, breadth of the rostrum, length of the tympanic bulla, and depth of the braincase at the anterior margin of the basioccipital. Ratios to the basilar length of the interorbital breadth, mastoid breadth, zygomatic breadth, and depth of the skull at the posterior borders of the upper molars are nearer to those of primulina. The relatively long rostrum, as represented by the orbitonasal length, is nearest to that of spadix. A young, almost subadult, female, no. 7, agrees with primulina in color, color pattern, and length of hind foot. The other external measurements are intermediate, but nearer those of primulina. Size of skull and teeth are as in longicauda. Relative proportions of parts of the skull are not diagnostic in specimens as young as this female. An adult female, skull only, no. 8, agrees with, or approaches nearer to, longicauda in size of skull and teeth and in relative proportion of every part studied. A juvenile, skull only, of questionable sex, no. 9, provides no diagnostic characters. On the basis of color, these specimens from Inland are distinctly nearer primulina. On the basis of cranial characters they are distinctly nearer longicauda. External measurements are intermediate and are a little nearer those of primulina. By placing the most weight on the cranial characters, the animals may be referred to longicauda. The same may be said of 2 skins, one skin with a skull, from Hastings, Nebraska. In each skin the color-pattern is as in primulina; in one the under side of the tail is nevertheless lighter-colored more as in longicauda and the skull, adult male 121651 American Museum of Natural History, approaches nearer to primulina in narrowness but has the large teeth of longicauda. Intergradation with neomexicana is suggested by one specimen, no. 7936, Univ. Kans., from Thomas County, Kansas, which has well-developed white facial markings. The specimen, no. 180, Kansas Agric. College, from Glasco, is mounted, of large size, in white winter pelage, and lacks external measurements. On the basis of its obvious large size, and a hind foot measurement of 49 millimeters obtained from the mounted skin, the animal is provisionally referred to longicauda rather than to primulina. Putorius culbertsoni is a name now credited to Coues (1877:136). Although Coues probably intended only to indicate that Baird wrote this name on the labels of two specimens in the mammal collection of the Smithsonian Institution, Coues gave an "indication" of the application of the name by publishing at the same time the catalogue numbers of specimens whose labels bore the name and thus, in accordance with article 21 of the International Rules of ZoÖlogical Nomenclature, himself becomes the author of the name. Of the two specimens mentioned by Coues, only the first recorded by him, no. 4320 (with skull no. 37995, U. S. Nat. Mus.), can now be found. Fortunately, the skull of this specimen labeled (see Lyon and Osgood, 1909:218) as taken at Fort Laramie, Wyoming, is well preserved. Its only defects are a fracture in the left zygomatic arch and the absence of parts of each of the first lower molars. In deciding on the subspecific application of the name Putorius culbertsoni Coues, the skull of the type must be principally relied upon, for there is available only one other specimen, a skin only (no. 12596, U. S. Nat. Mus.), from the same place, and it, like the type, is in white winter pelage and lacks flesh measurements. The ranges as now known of three subspecies of Mustela frenata approach near to Fort Laramie. These are M. f. longicauda, M. f. alleni, and M. f. nevadensis. The skull of the type of culbertsoni is not typical of any one of the three mentioned races. The small size of its teeth and relative (to basilar length) shallowness of the frontal region of the skull through the postorbital processes of the frontal are as in nevadensis. The zygomatic arches are not so greatly expanded as in some specimens of longicauda and are more like the average for nevadensis or alleni, as also is the relatively (to basilar length) long orbitonasal length. However, each of these characters is subject to variation and alone is not surely diagnostic, especially toward the margin of the range of any one of the subspecies concerned. The same may be said of the relatively great breadth of the skull interorbitally—a feature typically found in longicauda. More important, in my estimation, is the large size of the skull; all parts measured (excepting the teeth, the depth at the posterior border of the last upper molars, the zygomatic breadth, and the depth of the tympanic bullae) equal or approach nearest to the average for males of longicauda of similar age. The small size of alleni prevents its identification with culbertsoni. The question of application lies between nevadensis and longicauda. If the long-tailed weasel at Fort Laramie is found to be referable to the race earlier named longicauda, no change in current nomenclature will be effected. If, on the other hand, the long-tailed weasel from Fort Laramie is found to be referable to nevadensis this name will have to fall before the earlier proposed name culbertsoni. There is, however, a third possibility, namely, that the long-tailed weasel of the Transition and Upper Sonoran zones of southern Wyoming and northern Colorado, as for example, at Lay, Colorado, may represent a recognizable race characterized by size about as in longicauda, relative proportions of skull about as in nevadensis and coloration intermediate, to which the name culbertsoni may apply. For more detailed discussion of this possibility, see remarks under M. f. nevadensis. Satisfactory application of the name Putorius culbertsoni Coues requires an adequate series of adult specimens, of both sexes in the summer coat with external measurements taken in the flesh, from the type locality and like material from elsewhere in southern Wyoming. On the evidence furnished by the skull of the type of culbertsoni, that name tentatively is placed in the synonomy of longicauda. Only 2 of 25 adults examined for malformation of the frontal sinuses by parasites showed evidence of disease.
Mustela frenata oribasus (Bangs)Long-tailed Weasel Plates 16, 17, 18, 31, 32, 33 and 40
Comparison with longicauda reveals that, on the average, skulls of males are larger, relative to the basilar length broader across the mastoids, shallower through the braincase as measured at the anterior end of the basioccipital exclusive of the sagittal crest, with longer rostrum. Compared with nevadensis, the skull averages larger in all measurements taken, and has a relatively broader rostrum, relatively greater mastoid breadth and a braincase which is shallower relative to the basilar length. By weight, the skull of nevadensis is a fourth lighter, and in linear measurements 5 to 18 per cent smaller. Remarks.—Some of the specimens from Montana, which here are referred to oribasus, more than half a century ago were listed by Coues (1877:138) under the name longicauda. It was not until 1899 that this race was given a name by Bangs, who at that time (1899B:81) accurately made out the distinctive color features. Distinctive cranial characters cannot be described with assurance even now because there still are too few specimens. The type specimen, at one time examined by the present writer, has on the stuffed skin no well-developed mammae, scrotal pouch, or other visible sexual part. Probably the collector's sex mark for female is correct. As judged by the two skulls of subadult males from the Barkerville region, individuals of this race attain larger size than do those of longicauda. On the basis of larger size than either longicauda or nevadensis, the specimens from the Rocky Mountains of Montana and two from northern Wyoming are referred to this race. The short, wide, flat, tympanic bullae, relatively great mastoidal breadth, and some other features of the specimen from Donovan, Montana, point toward oribasus, whereas nearly as many more cranial features, in this instance mainly differences in size, are indicative of nevadensis to which race the specimen might almost equally well be referred. Another male from Darby, in the Bitterroot Valley of Montana, has a slightly longer hind foot than those from Florence, but a female from Hamilton, agrees more nearly with nevadensis. The average of all the specimens from the Bitterroot Valley is a little nearer oribasus. Four skulls from Buffalo, Wyoming, here referred to nevadensis show approach to oribasus in size of skull. The specimens from Big Snowy Mountains, and the Highwood Mountains of Montana are too young clearly to show size of the adult skull, but are distinctly darker colored than longicauda of the plains country proper. Of two subadult females from Tacy, Montana, the color of the one in summer pelage is distinctly nearer that of oribasus and nevadensis than it is to that of longicauda to which some approach in color might be expected. The reduced size of both of the specimens is further suggestive of nevadensis and it may be that adult specimens from these more eastern mountainous areas in Montana will show that nevadensis is the name proper to apply to animals of this region. Intergradation with nevadensis is suggested by specimens collected from along the upper reaches of Okanagan Lake, British Columbia, by Major Allan Brooks and Mr. J. A. Munro and by a series of skulls from Ione, Pend Orielle County, Washington, lent me by Mr. Walter Dalquest. At each place, the average of all specimens is nearest to that of nevadensis. Specimens from near Waterton Lake show several steps in the transition from the light-colored longicauda type of coloration to the darker coloration characterizing oribasus. One taken here, at a time when the body of water referred to seems to have been known as Chief Mountain Lake, is barely dark enough to be placed with oribasus. Two other specimens from across the Canadian Border labeled as "Waterton Lake Park" are slightly lighter colored above, and on this account are placed with longicauda. The two adult males from Lillooet, British Columbia, are referable to oribasus although neither is quite typical. One has a saturated coloration suggestive of that of altifrontalis and the skull is shorter and broader than in other specimens of oribasus. The female from Lillooet, skin alone, no. 916, Prov. Mus., B. C. is small for oribasus. The female, no. 1539, collection of Kenneth Racey, from Alta Lake, in brown winter pelage, in almost every measurement falls nearly midway between altifrontalis and oribasus but slightly nearer the latter. The skull from Chezacut and 3 animals from Wistaria, British Columbia, probably are females and show a greater average size than specimens from farther to the southeast. For example, the basilar length of the skull, 44.8 (44.3 to 45.1), exceeds that of the type specimen. The animals from Wistaria on Ootsa Lake furnish the northwesternmost station of occurrence of which I have record for this subspecies. The northernmost records of occurrence, at "Clearwater River, Peace River, B. C," and at Little Prairie, are furnished by a white skin without skull, no. 257450, U. S. Nat. Mus., purchased on August 2, 1932, at the place mentioned by W. H. Sheldon and Richard Borden, and a skull with white winter skin, no. 3585, Provincial Museum, British Columbia, respectively. The characters distinguishing longicauda and oribasus are not shown by white winter skins; the skull shows some features of longicauda, and the reference of these specimens to oribasus rather than longicauda is tentative. Only the skull from Little Prairie shows evidence of infestation of the frontal sinuses by parasites. In the Barkerville area of British Columbia, Mr. and Mrs. Thomas T. McCabe obtained only 2 skulls of this subspecies from a total of 238 weasel skulls gathered by local trappers. The others were Mustela erminea.
Mustela frenata alleni (Merriam)Long-tailed Weasel Plates 18, 19, 20, 31, 32 and 33
Remarks.—Animals of this subspecies were described and named by Merriam in 1896 as a distinct species on the basis of two or possibly three specimens from the Black Hills of South Dakota and the name seems never to have been applied to specimens from other regions. Vernon Bailey obtained only the one specimen, the type, on his trip in 1888, but two more were obtained for the American Museum of Natural History by Walter Granger in 1894. Mustela frenata alleni combines the light coloration of M. f. longicauda with the small size of M. f. nevadensis. Indeed, the size may average less than that of nevadensis. M. f. alleni seems to reach its extreme of small size in the Black Hills of South Dakota. Specimens from Mitchell, Scottsbluff County, Nebraska, here referred to alleni are of larger size and in this respect are intermediate between the subspecies alleni and longicauda. Of the two specimens available from Chadron, Nebraska, and here referred to as longicauda, the female, M1 #6, is almost exactly intermediate in size between alleni and longicauda, whereas the male, M1 #11, is as large as the average-sized longicauda. None of the nine skulls (5 adults) shows malformation resulting from the infestation of the frontal sinuses with parasites. Mustela frenata arizonensis (Mearns)Long-tailed Weasel Plates 19, 20, 21, 31, 32 and 33
Compared with the skull of M. f. nevadensis, that of arizonensis is smaller, less heavily ridged and has more inflated tympanic bullae and a relatively greater mastoid breadth. Comparison with the skull of M. f. neomexicana is made in the account of that subspecies. Remarks.—In 1891 Mearns (234-235) named this weasel as a full species on the basis of two individuals taken by him in 1886 and 1887. Since that time only a few additional specimens have been preserved. Only four are adults. Although this material does not permit of a definition of the subspecies as precise as could be wished, still, it clearly shows that the animals from the plateau region of Arizona are recognizably different from those farther north in the Sierra Nevada of California and those of the Rocky Mountains and Great Basin region northward to the Canadian border. These more northern animals have gone by Mearns' name, arizonensis, since the date of its proposal until 1939 when the name nevadensis was proposed. The smaller size, especially of the skull, and the greater inflation of the tympanic bullae are the outstanding characters which distinguish arizonensis from the similarly marked nevadensis. The bullae are relatively much inflated throughout but especially so on the posteromedial parts. Although the three adult males and two subadult females available of this subspecies are smaller in most parts measured than any of the scores of nevadensis of similar age that have been measured, overlap in size probably will be found as additional specimens of arizonensis become available. A young female, no. 18513, coll. D. R. Dickey, from Little Spring, does have certain cranial measurements as large as are found in the minimum-sized nevadensis from farther north. Intergradation with the two subspecies whose geographic ranges adjoin that of arizonensis is indicated by specimens at hand. One of these is the adult male from 25 miles southeast of Flagstaff, which shows decided approach to neomexicana, in color and in possessing white facial markings less well developed than in neomexicana. Even better developed white facial markings, with intervening blackish coloration, are displayed by no. 148271, U. S. Nat. Mus., from 8500 feet altitude on Willow Creek, New Mexico. This subadult female shows approach to neomexicana also in larger size of the skull and entire animal. The great inflation of the posterior part of each of its bullae and the dark color of the upper parts are characters of arizonensis. The color of the underparts stops at the ankles leaving the hind feet dark colored, in which respect the specimen is unlike either neomexicana or arizonensis. If additional specimens showing the same characters as this one be found at other nearby localities they probably should be given recognition as a separate subspecies. For the present it seems best to regard the specimen merely as an intergrade. Although it might, with almost equal propriety, be referred to either neomexicana or arizonensis, the specimen is here placed with the latter. The subadult male from Springerville, Arizona, is of larger size than the topotypical male of arizonensis and in this respect shows slight approach to nevadensis. The narrower mastoidal breadth and slightly less inflated tympanic bullae of the male from the Kaibab Plateau may reflect merely individual variation or may represent intergradation in these features with nevadensis. The statement made by Merriam (1896:22) that, "The type specimen ... is an immature female and is of unusually small size. A male obtained by him [Mearns] near the same place is of the normal size, as is another male in the Department collection from Springerville, Ariz., collected by E. W. Nelson," needs correction. The female is not immature. The specimen obtained by Mearns near the same place probably refers to Amer. Mus. No. 2489, from Quaking Asp Settlement, which lacks both the skull and external measurements. As stuffed it is of small size for a male. The male from Springerville, as shown by the external and cranial measurements, is not of normal (i. e. average) size, but is smaller than the average for the other populations of similarly colored weasels referred to by Merriam (op. cit.) as arizonensis but here described under the name nevadensis. None of the skulls shows signs of infestation of the frontal sinuses by parasites.
Mustela frenata nevadensis HallLong-tailed Weasel Plates 19, 20, 21, 33, 34, 35 and 39
Compared with the skull of M. f. longicauda, that of both sexes averages smaller in every measurement taken. Males of nevadensis, on the average, relative to the basilar length, are narrower in the interorbital region and across the zygomata but have the orbitonasal length greater. Stated in another way, the rostrum of longicauda appears to be shorter and broader and the zygomata are more expanded. Females of nevadensis, on the average, relative to the basilar length are narrower across the mastoid processes and zygomata and have the braincase deeper at the anterior margin of the basioccipital. Also in nevadensis the mastoid processes do not project so far laterally beyond the braincase, the lambdoidal crest and postorbital processes are less well developed and except in the interparietal region, the temporal ridges hardly meet and they form a sagittal furrow rather than a low sagittal crest which characterizes adult females of longicauda. Each of these differences separating the females of longicauda from those of nevadensis are of the same nature, although not necessarily of the same degree, as those which appear in longicauda with increasing age. The differences mentioned above are readily appreciable when series of specimens are compared. However, none of the differences is of great degree, and most parts of the skulls of the two subspecies are of similar relative proportions. Even so, there is but little overlap in actual size. Comparisons with the skulls of M. f. oribasus, alleni, neomexicana, arizonensis, inyoensis, pulchra, xanthogenys, munda, saturata, oregonensis, washingtoni, altifrontalis, and effera are made in the accounts of those subspecies. Remarks.—The populations to which the name nevadensis at present is assigned have gone by the name arizonensis since Mearns proposed this name in 1891. Before that time Coues (1877:141) had included individuals of this race under the name Putorius longicauda. Among the populations here assigned to M. f. nevadensis, there is some geographic variation but it is of lesser degree than in most other species of mammals which range over the same region. Comparison of 20 adult males from the Rocky Mountains of Colorado with 25 adult males from a place as far distant as the Sierra Nevada of California shows that the two populations closely resemble each other. The specimens from Colorado average a trifle wider across the zygomata, have a longer body and therefore relatively shorter tail, and, except in southern Colorado, a slightly longer hind foot. Comparison of ten adult females from each of the two areas reveals that those from Colorado have a markedly longer hind foot, and a tail somewhat shorter relative to the length of the body. The mentioned differences are the only ones found among the great number of points investigated, except that as remarked by Merriam (1896:23) the Sierran animal has the yellow of the underparts reaching farther up under the chin, the underside of the tail on the average is more suffused with yellowish and the white on the upper lip is more extensive. As regards the last mentioned feature, my check of 34 skins from Colorado reveals that the white extends all the way around the upper lip in every specimen but one, whereas in 69 specimens from the Sierra Nevada the white extends all the way around the upper lip in only 39. However, as further remarked by Merriam (loc. cit.), not only this but the other color features are inconstant in addition to being slight. When the occurrence of the dark spots near the angles of the mouth are tabulated, it is found that in 33 Colorado-taken specimens they are absent in 19, faintly indicated in 13, and well developed in 1. In 62 California-taken specimens they are absent in 37, faintly indicated in 20, and well developed in 5. In northwestern Colorado, southern Wyoming, and possibly through the Bear River Divide into southeastern Idaho, long-tailed weasels here referred to nevadensis approach longicauda in large size and occasionally in other features, more closely than do specimens of nevadensis from most other places in its range. This tendency is thought to be significant for much of the area in question lies in or below the Transition Life-zone, the same life zones in which farther to the eastward true longicauda occurs. One specimen that illustrates this approach to longicauda is an adult male, no. 2334, collection of E. R. Warren, from 6160 feet, Lay, Routt [now Moffat] County, Colorado. In large size and, relative to the basilar length, shorter rostrum and shorter tympanic bullae, it agrees with longicauda but the darker color and, relative to the basilar length, narrowness of the rostrum, interorbital region, zygomatic expanse and the shallowness through the region of the postorbital processes place it with nevadensis. Of two other specimens from Steamboat Springs, Routt County, a young male, no. 4010, in the collection of E. R. Warren, has a hind foot (50 mm.) as long as in longicauda; and the other, no. 138195, U. S. Nat. Mus., an adult male, agrees well enough in size and proportions with nevadensis but has the coloration typical of longicauda. From Wyoming, one subadult female, no. 177553, U. S. Nat. Mus., from Garrett, is intermediate in size and coloration but is nearer to nevadensis in these particulars, as it is in all other points considered except size of the molar teeth which are as large as in longicauda and larger than in any female nevadensis from Colorado or California. Another female, an adult, no. 179304, U. S. Nat. Mus., from Lonetree, Wyoming, agrees with longicauda in size of skull. Indeed, ten of seventeen cranial measurements exceed the maximum for Colorado-taken nevadensis. Where differences exist in relative proportions of the skull as expressed in percentages of the basilar length, the specimen approaches nevadensis in 5 instances and longicauda in only 3. The color is intermediate but much nearer that of nevadensis with which the animal agrees also in external measurements. Ten subadults (5 of each sex) from within 12 miles of Laramie (not Fort Laramie) show greater resemblance to nevadensis but definitely approach longicauda. Average external measurements are: ?, 408, 155, 44; ?, 361, 134, 40. The two other specimens examined from this general locality, a young female, no. 2711, Mus. Vert. ZoÖl., from Fort Bridger, and a subadult female, no. 188377, U. S. Nat. Mus., from Bridger Pass, show no departures from nevadensis of similar age. The specimens from scattered localities in the Transition Life-zone of northwestern Colorado and southern Wyoming are larger than nevadensis is elsewhere, and also in certain other features resemble longicauda of the plains to the eastward. Everything considered, the animals in question are much more like nevadensis than longicauda. Study of more specimens, especially from Wyoming, might provide grounds for recognizing as a different subspecies the animals in this large area comprising parts of Colorado and Wyoming from which so few specimens now are available. Possibly the name Putorius culbertsoni Coues would apply. Decision on that point will require adequate material from the type locality, Fort Laramie. See discussion of this name under M. f. longicauda. In southeastern Idaho males are larger than they are at most other places within the range of nevadensis. An average of 7 adults and subadults from Pegram, Montpelier, Springfield, and the vicinity of Pocatello, reveals, when compared with the average of nevadensis from Colorado and that of longicauda from the Great Plains, that this population from southeastern Idaho is nearest to longicauda in linear measurements of the orbitonasal length, mastoid breadth, length of tympanic bullae, and as expressed in percentage of the basilar length, length of tooth-row, breadth of rostrum, and zygomatic breadth. In all other points of size, relative proportions and color, the animals approach nearer to, or actually agree with, nevadensis. The specimens commented upon clearly show intergradation between nevadensis and longicauda. Similarly, the specimens from Scottsbluff County, Nebraska, here referred to M. f. alleni, by their larger size suggest intergradation of that subspecies with the larger nevadensis-longicauda stock although the approach is more toward longicauda than nevadensis. Between oribasus and nevadensis, however, there is no lack of material showing intergradation. As set forth in the account of oribasus, specimens from Montana are truly intermediate structurally as well as geographically. Intergradation with washingtoni is shown by specimens from the northern part of the Cascade Range in Chelan and Okanogan counties, Washington. The adult male, U. S. Nat. Mus., no. 235183, from Bald Mountain, is referable to washingtoni on the basis of cranial characters but all the other adult and subadult specimens examined from Chelan and Okanogan counties are nearer nevadensis on the basis of cranial characters. Indeed, some show no approach to washingtoni in cranial characters. As might be expected on geographic grounds, the specimen from Easton, U. S. Nat. Mus., male subadult, no. 116870, shows approach to washingtoni. This is true of the coloration of the hind limbs, small size of the tympanic bullae, and relatively greater length of the preorbital part of the skull. However, the greater width of the light color of the underparts and relatively great breadth across the mastoid processes and zygomatic arches are points of agreement with nevadensis. Similarly, a series of 7 specimens from the Entait River, 20 miles above its mouth, in tone of color is nearer to washingtoni, as is one of the two skulls of adult males in length of the preorbital region. However, in greater breadth of the skull otherwise, and in the relatively great width of the light color of the underparts, the animals are nearer to nevadensis, to which they are here referred. Some of these characters mentioned above in which departure is shown from typical nevadensis are characters that show approach to altifrontalis. This is especially true of the more intense coloration and restriction of the color of the underparts. Complete intergradation with effera is shown by specimens from southern Oregon. The change from small effera to the larger nevadensis here is gradual; consequently in northeastern California and southern Oregon the size increases gradually to the northward. Specimens showing complete intergradation with oregonensis and saturata are wanting. However, one specimen from Crescent Lake suggests oregonensis in having near (18) apricot yellow underparts such as occur frequently in oregonensis. Also some specimens from northern California approach saturata in having the color of the underparts reduced in the extent to which it reaches out on the under side of the tail. This fact and the consideration that the two races are less different from one another than are other kinds which definitely are known to intergrade leave no doubt but that material from the intervening localities would show complete intergradation. Intergradation between nevadensis and munda is indicated by specimens from South Yolla Bolly Mountain, Trinity County, which are commented on at greater length in the account of M. f. munda. M. f. inyoensis is so closely related to nevadensis as to leave no doubt that specimens from suitable localities will show actual intergradation. That intergradation occurs directly with the bridled weasel of the interior valleys of California, M. f. xanthogenys, is shown by specimens from along the west-facing flank of the southern part of the Sierra Nevada. Probably intergradation occurs all along the Sierra Nevada on the western slope but specimens are lacking to show this. Weasels are known to occur in the foothill territory and the lesser attention given to this region by mammal collectors than to the higher parts of the mountains may explain the lack of preserved specimens. Individual specimens, here referred to nevadensis, but, showing varying degrees of approach to xanthogenys are as follows: A female from Hume; a male and a female from 8000 feet elevation, Monache Meadows; a male from 9800 feet elevation on the east fork of the Kaweah River; and 7 specimens, probably one family, from one-half mile south of Mineral King, 7850 feet. Of the specimens from 7850 feet, the adult male has no light facial markings and the head is only slightly darker than the back. The adult female has much restricted, light facial markings and the intervening areas are darker than in the male. The five juveniles trapped in the same burrow as the female, each has more extensive light facial markings than the adult female although the area of this varies from only slightly more than in the female to as much as in typical specimens of xanthogenys. Also, the dark color of the head in these five specimens averages darker than in nevadensis and more as in weasels to the southwestward especially latirostra. One of the five juveniles is lighter colored over all of the upper parts than nevadensis and is suggestive of xanthogenys in this respect. Finally, the adult male has on the underparts small spots of ochraceous orange suggestive of latirostra and some individuals of pulchra. No. 30655/42628, U. S. Nat. Mus., taken on Mount Whitney, also shows white facial markings and some other features of the valley-inhabiting xanthogenys. A suggestion of intergradation with arizonensis is furnished by specimens, referred to that race, from Springerville and the Kaibab Plateau. No specimens happen to be available from the region in which intergradation would be expected between nevadensis and neomexicana. Since neomexicana and arizonensis intergrade it is probable that nevadensis also will be found to intergrade with neomexicana. In summary, nevadensis is judged to intergrade with each of the subspecies of Mustela frenata whose range adjoins that of nevadensis. This subspecies is remarkably free from injury to the frontal sinuses such as result from the presence of parasites. In 98 adults from Oregon, California, Nevada, and Colorado, no malformation was noted. Only 1 of the 26 specimens from Washington was malformed and it was an intergrade with washingtoni. The single adult from New Mexico was diseased, as were 3 of the 6 from British Columbia, 1 of the 20 from Idaho, and 1 of the 7 from Utah.
Mustela frenata effera HallLong-tailed Weasel
As compared with the skull of M. f. nevadensis that of effera seems, on the average, to have the preorbital part relatively smaller. Otherwise, the skull is a miniature of the skull of nevadensis, averaging about eight per cent smaller in linear measurements and weighs twenty-two per cent less. Comparisons of the skull with those of M. f. washingtoni and M. f. oregonensis are made in accounts of those subspecies. Remarks.—This geographic race has long borne the name of Mustela arizonensis (Mearns). Small size differentiates effera from nevadensis and specimens have been allocated to one or the other subspecies on the basis of size, or average size when several individuals are available from one locality. Complete intergradation with each adjoining subspecies is indicated by numerous specimens, more of which are assigned to these adjoining subspecies than to effera itself. The minimum of size in M. f. effera is found in the Blue Mountain region of northeastern Oregon. Specimens from the area intervening between these mountains and the Cascades average larger but are nearer the mean of typical effera than they are to the means of washingtoni, oregonensis or nevadensis. Two males, nos. 204883, adult, and 204884, young, from Sisters, Oregon, near the eastern base of the Cascades, show approach structurally to M. f. washingtoni as it is represented at the nearby locality, Permilia Lake, at the west base of Mount Jefferson. Everything considered, however, the two specimens from Sisters are nearer to effera. A male from Condon, Oregon, shows approach to the Cascade race in slightly increased size. No perfect skulls of adult females are available from the part of northwestern Oregon in which effera reaches its typical state of development as judged by the small size of the skull of the adult male. Skulls of adult females are available, however, from more nearly marginal localities. These, though smaller than in nevadensis, show relatively less difference in size when compared with nevadensis than do skulls of males. Even so the females at these marginal localities are smaller than those of nevadensis of comparable age and adequate material of adult female effera from the region where the males attain their extreme of small size probably will show about the same relative difference in size between nevadensis and effera as is known to exist between the adult males of these two subspecies. The small size of a subadult female, no 74631, U. S. Nat. Mus., from Asotin, Washington, constitutes partial basis for this opinion. Of 14 adults examined none showed malformation of the frontal sinuses due to infestation by parasites.
Mustela frenata washingtoni (Merriam)Long-tailed Weasel Plates 19, 20, 21, 34, 35 and 36
Compared with M. f. nevadensis, the skull of the male of washingtoni averages more slender, as shown by the mastoid and zygomatic breadths and has the preorbital part longer, on the average, as shown by the greater ratio (to the basilar length) of the length of the tooth-rows and orbitonasal length. Also, on the average, the postorbital constriction is longer than in nevadensis and the tympanic bullae are smaller. In females, the skull is lighter, the tooth-rows are shorter, the tympanic bullae are smaller, and the preorbital part of the skull is shorter and narrower as shown by the orbitonasal length and interorbital breadth. Except that the tympanic bullae are actually, although not relatively, smaller in males of effera, it differs from washingtoni in the same way as does nevadensis as regards relative proportions, but, of course, the actual difference in size is greater since effera is smaller than nevadensis. Comparison of the skull with that of oregonensis is made in the account of that subspecies. Remarks.—M. f. washingtoni was described and named in 1896 by Merriam as a distinct species. Subsequently, specimens which here are regarded as intergrades between altifrontalis and nevadensis, were classified as washingtoni. The external measurements given for the specimens from Mount Adams are those recorded on the labels in inches and fractions thereof. Instead of total length there sometimes is written "tip to tip." In the series of 19 winter-taken topotypes the hairs project beyond the end of the caudal vertebrae for an average distance of 28 (19-40) millimeters. If the hairs on the end of the tail were included in the measurements, 28 millimeters should be subtracted from the averages. Probably the measurements should stand as given, since an adult male topotype, no. 226758, U. S. Nat. Mus., taken subsequently by Walter P. Taylor measures 405; 152; 51. Mustela frenata washingtoni is not a strongly marked geographic race. In many features it is intermediate between M. f. altifrontalis and M. f. nevadensis. This is especially true of coloration. In the series from Mount Adams and that from Mount Rainier, some individuals have the light color of the underparts extended down the hind legs over the feet and over the proximal face of the ventral third of the tail as in nevadensis, whereas others from the same place have the light color of the underparts absent from the tail and extending no farther down the hind limbs than the knees. The light color of the underparts in the series of topotypes is so restricted that the transverse extent at the narrowest place amounts to only 24 (10-37) per cent of the greatest width of the color of the upper parts. This narrowness of the color of the underparts has been likened by Merriam (1896:18) to the condition in Mustela frenata noveboracensis. So it is, but it is similar to the condition found also in the geographically adjoining M. f. altifrontalis. Of the 37 skulls of subadults and a few adults, 11 had the frontal sinuses malformed as a result of infestation by parasites.
Mustela frenata saturata (Merriam)Long-tailed Weasel
The skull of the male of saturata, relative to the basilar length, is broader across the mastoids and narrower across the rostrum and interorbital region than that of nevadensis. Skull not known certainly to differ from that of oregonensis. Compared with the skull of munda, that of the male of saturata is smaller in every part measured except depth of tympanic bullae which averages 3.6 millimeters, rather than 3.5 as in munda. Also, the skull of saturata has a less-marked postorbital constriction, is less heavily ridged, less angular, does not have the impressions of the temporal muscles carried so far forward on the frontal bones and is relatively much narrower across the zygomatic arches. Remarks.—In 1896, Merriam named M. f. saturata as a distinct species on the basis of one specimen, taken by Clark P. Streator at Siskiyou, Oregon, and a second specimen taken the year previously by Allan C. Brooks at Chilliwack, British Columbia. On the basis of these two specimens, Merriam (1896:22) ascribed to the race a range "... on the Cascade and Siskiyou mountains of Oregon and Washington, reaching a short distance into British Columbia." Since that time, this name, saturata, has been employed for the dark-colored weasels, of the coastal region of Oregon, Washington, and extreme southwestern British Columbia, which here are arranged under the name M. f. altifrontalis. M. f. saturata proves to be restricted to the humid mountainous region inland from the coast in northern California and in the Siskiyou Mountains of southern Oregon. Its range is separated by that of M. f. oregonensis from the range of the darker-colored, deeper-skulled, M. f. altifrontalis of the humid costal region proper. On May 5, 1933, Mr. Clark P. Streator, informed the writer that he remembered taking the type specimen of Mustela frenata saturata (Merriam) in the town of Siskiyou, Oregon. The exact place, he said, was reached, at the time of his work there, by going one or two blocks east of the depot, then through a garden into the thick woods where there were springs and numerous burrows of the rodent, Aplodontia. Two other weasels labeled as taken at Siskiyou, on September 28 and 29, 1893, by Mr. Streator, are much lighter colored than the type of saturata and have the color of the underparts extended distally on the hind legs to the tips of the toes and in other features of coloration are more like nevadensis, the subspecies to which they are referred, than saturata. Probably these did not come from exactly the same place that the type specimen of saturata did. Although Mr. Streator does not remember the taking of these particular specimens in 1893, he does remember that on this visit to Siskiyou, he walked southward through the railroad tunnel and collected on the opposite side of the ridge from Siskiyou. Here on more southern exposures, the country was markedly different than in the thick forest at Siskiyou. Probably these two specimens taken in 1893, and referred to nevadensis, came from a little way south of Siskiyou and from a different habitat and life-zone than the type specimen of M. f. saturata. Of the 6 specimens examined, only one, the type, shows malformation of the frontal sinuses such as result from infestation by parasites.
Mustela frenata altifrontalis HallLong-tailed Weasel Plates 1, 19, 20, 21, 34, 35 and 36
Compared with the skull of M. f. washingtoni that of each sex of altifrontalis averages slightly larger in every measurement taken, except measurements of teeth which are approximately the same, and is relatively deeper through the frontal region and through the braincase as measured at the anterior margin of the basioccipital. Skulls of females of altifrontalis have a relatively broader interorbital region. Skulls of males of altifrontalis further differ in having relatively, as well as actually, longer tympanic bullae, relatively lesser orbitonasal length and a greater relative breadth across the mastoids and across zygomata. Compared with M. f. nevadensis, the skull of the male of altifrontalis averages slightly larger and heavier although the skulls of females are of approximately the same size and weight. Relative to the basilar length, the skulls of both sexes are deeper through the braincase and narrower across the mastoids; the rostrum is broader, especially in males; the tooth-rows are shorter and the interorbital breadth less, especially in females. Comparison with the skull of oregonensis is made in the account of that subspecies. Remarks.—Until the present study was begun, animals of this race have gone under the name Mustela saturata (Merriam). The United States National Museum has a juvenile taken, in 1858, by Wayne at Astoria, O. T.; the Samuel N. Rhoads collection contained one specimen taken in 1891, at Tacoma, Washington; one in the Bangs' collection was taken at Chilliwack, British Columbia, in 1895, and the Field Museum has one taken on the Olympic Peninsula in 1898. The best material is that collected by Alex Walker, at Tillamook, Oregon. Intergradation with nevadensis is indicated by several specimens. The coloration of the one adult female, no. 90, Chas. R. Conner Mus., from Swamp Creek, Washington, has the color of the underparts extended down the hind legs over the feet, and over the proximal third of the ventral face of the tail as in nevadensis although the other two specimens from the same place have the color pattern of altifrontalis. Of the four specimens from British Columbia referred to this subspecies, only the specimen from Chilliwack is typical as regards color pattern. The one from Cultus Lake has the color pattern of nevadensis and might be referred to that race almost as well as to altifrontalis. The two specimens from Lihumption Park are intermediate between the two races in tone of color. Neither has the color of the underparts extended onto the tail or continuously over the hind feet as in nevadensis but each does have the color of the underparts less restricted and of lighter hue than in altifrontalis. Only one of the specimens, no. 7848 Canad. Nat. Mus., from Lihumption Park is adult and it has a skull which agrees with that of altifrontalis rather than nevadensis. After writing the above, a good representation of the weasel population along the eastern side of Puget Sound was made available by friends in that area. Study of the weasels from there shows that their color is intermediate between that of altifrontalis and nevadensis. On the whole, they (specimens from Bellingham, for example) resemble one subspecies about as much as the other. In cranial characters some specimens, in certain features, approach nevadensis but most specimens agree with altifrontalis and all are more nearly like altifrontalis to which race all are referred. The color of these animals is to me indistinguishable from that of washingtoni. The color of washingtoni is merely intermediate between that of nevadensis and altifrontalis. Nevertheless, the race washingtoni has cranial characters (long narrow skull) which set it off from both altifrontalis and nevadensis. This shape of skull is not found in the specimens from along the eastern side of Puget Sound; these animals have skulls like that of altifrontalis and when departures from this occur they are in the direction of nevadensis and not washingtoni. The above, then, explains why specimens which are colored like those of washingtoni are not referred to that race but instead to the race altifrontalis. Of 23 adult skulls examined, 19 have the frontal sinuses malformed as the result of infestation by parasites.
Mustela frenata oregonensis (Merriam)Long-tailed Weasel Plates 19, 20, 21, 30, 34, 35 and 36
Because there is much geographic variation between specimens here referred to oregonensis, the person who is guided by the present account should keep in mind that results, here reported, of comparisons of the skull with those of other races, were obtained by employing specimens of oregonensis from Carlotta and Eureka, California. These specimens from California are judged to have more of the characters of the subspecies munda than do specimens of oregonensis from more northern localities. Compared with that of M. f. washingtoni the skull of the male is shorter, especially in the preorbital region and is relatively broader across the mastoidal processes and zygomatic arches. The skull of the female is longer in the preorbital region, has a less cylindrical braincase and differs less from the male skull than is the case in M. f. washingtoni. Compared with M. f. effera, the skull of the male is smaller in every part measured and relative to the basilar length is broader across the mastoids and has relatively shorter tympanic bullae. From M. f. nevadensis the skull of the male differs in the same way except that size is about the same. The skull of the female oregonensis is more heavily ridged and is relatively broader across the mastoids than that of effera. From M. f. saturata, oregonensis is not surely known to differ in cranial characters. From M. f. munda, oregonensis differs in having the skull of both sexes smaller, and on the average, in all parts measured, has a less marked postorbital constriction, relatively narrower interorbital region and relatively more expanded zygomata. From M. f. altifrontalis, males of oregonensis differ on the average, in having larger teeth, and relative to the basilar length, a greater mastoid breadth and a shallower braincase as measured at the anterior margin of the basioccipital. Females of oregonensis differ in larger average size of skull, except for breadth of rostrum and interorbital breadth which, therefore, are relatively less in oregonensis, as also is the relative depth of the skull measured at the posterior borders of the upper molars and at the anterior margin of the basioccipital. However, skulls of females of oregonensis have relatively longer tooth-rows and are relatively broader across the zygomata and mastoidal processes. Remarks.—In 1896, Merriam named oregonensis as a subspecies of the California bridled weasel on the basis of a single specimen taken by Clark P. Streator. Three additional specimens were acquired in later years, by workers of Dr. Merriam's bureau, from near the type locality and specimens from farther north in Oregon have been accumulated at the University of Oregon. The most satisfactory material is that saved from Humboldt County by the late H. E. Wilder, which, when brought together, is adequate to give some idea of the range of variation that can be expected in a given population. Of two specimens from Goldbeach, one shows approach to altifrontalis in that the color of the underparts stops at the ankle, and in one, the angle of the mouth is dark colored. Specimens from Eugene and vicinity lack the white facial markings, and in this feature approach the adjoining washingtoni-effera-nevadensis stock. A specimen from 6 miles south of Medford shows approach to saturata in the interruption, on the ankle and lower tibial region, of the color of the underparts. One adult female, no. 1413, Univ. Oregon, from the Rogue River Valley, 13 miles southwest of Grants Pass, stands out prominently, among the other specimens from extreme southern Oregon and northwestern California, by reason of the near (18) Apricot Yellow color of the underparts, but this same color occurs in specimens from the more northerly localities of Buchanan, Eugene, Vida Fish Hatchery, and McKenzie Bridge, as well as in no. 2178, Univ. Oregon, from Cresent Lake. The last mentioned specimen is here referred to nevadensis. Two females referred to oregonensis from southern Oregon differ so greatly in size of skull that they challenge one's imagination in any attempt to provide an explanation for so wide a range of variation in one subspecies. One of these, no. 244520, U. S. Nat. Mus., is an adult female from Medford. The other, no. 224034, U. S. Nat. Mus., is a subadult female (though labeled male) from 43 miles northeast of Grants Pass. The skull of the adult from Medford has a basilar length of 41.5, upper tooth-rows, 16.1 in length, and a weight of 2.75 grams, whereas corresponding figures for the subadult are only 33.8, 12.9, and 1.4. Two other adult females are intermediate in size: No. 1413, Univ. Oregon, from 13 miles southwest of Grants Pass, Oregon, approaches the specimen from Medford in size, and the second specimen, no. 34325, Mus. Vert. ZoÖl., from Carlotta, California, is smaller. Not only is there a difference in length between the skulls of the two extremes of the females but this difference extends to all other dimensions of their skulls, and is most pronounced in the preorbital region. The differences in breadth of the braincase and other parts of the skull are relatively less than the differences in length. Differences of the same nature, although of lesser degree than found in the females, are to be seen in two males. The skull of an adult no. 51590, Mus. Vert. ZoÖl., from 6 miles south of Medford, has a basilar length of 46.4, upper tooth-rows, 17.6 mm. long, and a weight of 4.0 grams, whereas corresponding figures for the subadult type specimen from Grants Pass, are only 43.0, 16.2, and 3.3. The wide range of variation in size of skull of both sexes, together with the considerable variation in color pattern of the specimens here referred to oregonensis raises the suspicion that we are using the name in a composite sense; nevertheless, to recognize more than one subspecies with the material now available would be unwise. A subadult female, of abnormal color, no. 47149, Mus. Vert. ZoÖl., taken by Mr. H. E. Wilder at Carlotta, California, on December 20, 1930, in a region where weasels do not turn white in winter, is white, except for the black tip of the tail, but has a suffusion of orange. This specimen, discussed at greater length on page 43, is instructive in that it suggests that there are separate determiners for the brown and red elements of the pelage. It is interesting also as suggesting how natural selection may tend to eliminate from the population a conspicuous color-variation of this kind. At any rate, Mr. Wilder (Ms.) states: "This specimen was picked up in a field, where it evidently had been dropped by a hawk or an owl." The braincase of the skull is crushed in three places as though by a raptor's beak. None of the several other weasels, all normally colored, saved by Mr. Wilder from this general locality gives evidence of having fallen a victim to a raptor. Only 2 skulls of the 12 adults and subadults examined show malformation of the frontal sinuses such as results from the presence of parasites.
Mustela frenata munda (Bangs)Long-tailed Weasel Plates 1, 19, 20, 21, 22, 23, 30, 34, 35, 36 and 40
Compared with the skull of the male of nevadensis that of munda averages larger in every part measured and specimens from Point Arena are nearly as heavy again, have relatively more expanded zygomata and mastoid processes but are relatively narrower anteriorly as shown by the breadth of the rostrum, interorbital breadth and postorbital breadth. Also the braincase is less inflated anteriorly, the tympanic bullae are lower and the skull is more angular. Females show the same differences although in different degree. Compared with the skull of the male of M. f. nigriauris, that of munda from Point Arena averages larger in every part measured except for the length of the upper tooth-rows. Relative to the basilar length, the skull of munda averages broader across the mastoids and across the zygomata, is deeper through the braincase at the anterior end of the basioccipital, and has a greater development of the lambdoidal crest. Remarks.—The skin and part skull, no. 536/1849, U. S. Nat. Mus., taken by Lieutenant W. P. Trowbridge at San Pablo Bay, is the first specimen known to have been saved of this subspecies. Since 1899 when O. Bangs diagnosed munda as of small size, the weasel of the humid costal belt north of San Francisco Bay has been regarded as smaller than bridled weasels from farther south in the State. Actually, however, the weasel of the humid costal belt shares with M. f. pulchra the distinction of being one of the two largest weasels in California. M. f. munda may be a composite subspecies, for the variation in facial markings, in coloration otherwise, in external measurements and in size and shape of skull is great. At one time in the course of the present study, manuscript accounts of two subspecies were prepared for the animals now all called munda and there is still much justification for recognizing two subspecies, one, along the coast proper, the larger, darker-colored animal with reduced white facial markings and large, wide, heavily ridged skull from Point Arena, and 6 miles south of Laytonville, Mendocino County, along with the specimens from 5 and 6 miles west of Inverness, Marin County, and the other, an inland race, which is a smaller, lighter-colored animal with more extensive white facial markings and a smaller, narrower, skull, known by specimens from Point Reyes [station?], Nicasio, 15 mi. north of San Rafael, Freestone, Vallejo, and Mount Sanhedrin. The differences between these two lots of specimens are of great degree. However, a female from Fort Bragg proves to be no larger than three females labeled as from Point Reyes. Also, a male from 2 miles south and one mile east of Stewarts Point on the coast has a skull no larger than the animal from Vallejo, whereas the skin alone of an adult female from 3 miles south of Stewarts Point is large and agrees with the specimens from Point Arena. Consequently, no logical ranges can be worked out for the two variants with the material now available. Finally, the type specimen of munda is a "runt," smaller than any other male seen. This specimen, purchased by E. A. and O. Bangs from C. A. Allen, who collected and sold specimens widely, was labeled as from Point Reyes. So far as this place-name is concerned, it might refer to: (1) The point of land by that name which projects out into the Pacific Ocean, (2) an abandoned ranch house bearing that name at the head of Drakes Bay, 6 miles north and 3-3/4 miles east of the actual point, or (3) the railway station by the same name at the head of Tomales Bay, 12 miles east and 4-3/4 miles north of the actual point. Allen, himself, lived near San Geronimo (then Nicasio) about nine miles southeast of the Point Reyes railway station. All these places are in Marin County, but differ markedly as regards climate and flora. The first two are treeless, windswept and have much fog, whereas Point Reyes Station is more often sunny, and is situated in a shallow valley, inland, where the open grass-covered west-facing slopes meet the east-facing wooded ones. From which one of these three places the type specimen came, I do not know. The same may be said of the three female specimens labeled Point Reyes; two of these are in the United States National Museum and one in the Field Museum. The specimens in the Museum of Vertebrate ZoÖlogy from 5 and 6 miles west of Inverness and those from near the same place in the collection of John Cushing come from within a couple of miles or less of the Point Reyes represented by the abandoned ranch house. These specimens, as remarked above, agree with those from Point Arena in large size, reduced facial markings and wide skull. These are points of difference from the smaller variant suspected of being a recognizable subspecies. It is the smaller variant which the type specimen approaches in size, and with which it agrees in relatively well-developed white facial markings. This suggests that the type specimen came from Point Reyes Station rather than from either of the two other places bearing the name "Point Reyes," from one of which, as just stated, the variant of large size is known. The three females labeled "Point Reyes" also have well-developed white facial markings and are of lesser size than the female of similar age from Point Arena, Mendocino County. The presumption is that these three females also came from Point Reyes Station. The smaller, inland variant seems to agree in size, cranial characters, and coloration with M. f. nigriauris to the southward of San Francisco Bay, but lacks the black on the head which characterizes nigriauris. The larger variant, on which the description here used for munda is based, comprises animals which differ from nigriauris in larger size, darker color, reduced white facial markings, and larger, relatively wider skull. Both of the variants mentioned above are sharply distinct from nigriauris on the basis of coloration of the inside of the ear which is blackish in nigriauris like the dark facial markings, and in munda is colored like the back. M. f. munda lacks the dark facial markings; an occasional specimen has at most, a trace of the markings but this does not extend back so far as the ears. This difference, blackish versus non-blackish face, persists eastward of San Francisco Bay to at least as far as the Carquinez Straits, where a specimen of munda is available from 4 miles north of Vallejo and one of nigriauris from Glen Frazer Station on the south shore opposite Vallejo. Fig. 30. Map showing the geographic distribution of subspecies of Mustela frenata in California Intergradation with M. f. nevadensis and possibly with M. f. saturata is indicated by specimens from South Yolla Bolly Mountain, Trinity County. In them the external measurements and measurements of the skull are intermediate. Also the white frontal spot is much reduced in size. The white bars in front of the ears are absent in three specimens, and weakly developed in the other two. The relative proportions of the skulls as a whole are nearer those of nevadensis or saturata than munda. The skull of one of the three adult males and the skull of the adult female suggests M. f. oregonensis in certain features; for example, the dorsal outline of the skull in longitudinal axis is slightly convex as it is in oregonensis. None of the specimens shows malformation of the frontal sinuses such as results from infestation by parasites.
Mustela frenata xanthogenys GrayLong-tailed Weasel Plates 21, 22, 23, 28, 30, 34, 35 and 36
Compared with skulls of nevadensis from the Sierra Nevada, those of the two adult males from Fresno differ as follows: M1 wider (transversely); tympanic bullae narrower; preorbital part of skull smaller. Comparison with pulchra is made in the account of that subspecies. Compared with skulls of adult males of nigriauris, from Santa Clara County, the two skulls from Fresno are generally smaller and in basilar length, length of tooth-rows and measurements of the teeth fall below the minimum for nigriauris. Relative proportions of the skulls are approximately the same. Comparison with munda reveals essentially the same differences as does comparison with nigriauris except that the difference in size is greater. Remarks.—The name Mustela xanthogenys Gray was long applied to all the weasels of the interior valleys of California and of the coast of that state south of San Francisco Bay. Gray, when he named the species and when referring to it in later accounts, never defined the locality whence the specimen came more definitely than "California." In 1896, Merriam (1896:25) gave the type locality as "Southern California, probably vicinity of San Diego" and later writers have not contradicted him. The type specimen was obtained in the course of the voyage of the British ship Sulphur, under command of Sir Edward Belcher. Examination of Belcher's (1843, vol. 1, p. 129) narrative of the voyage indicates the following places in California at which the specimen of weasel, described by Gray, could have been obtained: Fort Ross, Bodega, vicinity of San Francisco Bay and up Sacramento River to the mouth of the Feather River, Monterey, Santa Barbara, Buenaventura, San Pedro, San Juan, and San Diego. Reginald I. Pocock has kindly compared the type specimen in the British Museum with several specimens sent for that purpose. In the first place, comparison of skulls shows that the type specimen is a member of one of the races north of San Diego. In the second place, comparison of skins shows that the inside of the ears are not blackish but similar in color to the back. In fact, Pocock writes under date of February 12, 1929, regarding the type specimen, that "It is practically uniformly colored from the snout to the base of the tail, there being scarcely a trace of the darkening of the head, or muzzle, observable in your specimens [those sent for comparison]." This character of coloration of the ear excludes all the weasels of the Coast region of California from San Francisco Bay southward, namely, M. f. latirostra and M. f. nigriauris. My own examination of this type specimen at a date later than that on which Pocock compared it satisfies me as to the accuracy of his statement above. Accordingly, the name xanthogenys would seem to apply to one of the two subspecies here called munda and xanthogenys. Perusal of Belcher's narrative of the voyage (loc. cit.) shows that little, if any, opportunity was afforded to obtain vertebrate specimens at Fort Ross or Bodega, both localities within the range of the subspecies here called munda. Furthermore, the type specimen is smaller than individuals of munda from 5 to 6 miles west of Inverness and from Point Arena with which the animals from Fort Ross and Bodega would be expected to agree in size. Weasels from along the north shore of San Francisco Bay are smaller than those on the coast north of the bay. Possibly the type specimen of xanthogenys came from the north side of San Francisco Bay but probably it came from the bank of the Sacramento River and almost certainly not farther up stream from San Francisco Bay than the junction of the Sacramento and Feather rivers. The statement of Belcher (1843, vol. 1, p. 129), regarding the trip up the Sacramento River as far as Point Victoria, lat. 38°46´47" north, and return to San Francisco Bay, that "Cuyote or jackal—fox, racoon, land otter, weasel, and squirrel were obtained" lends strong probability to the idea that this type specimen was taken along the Sacramento River, possibly in the vicinity of the existing city of Sacramento. Unfortunately no specimens are available from the Sacramento Valley. If some were available, a comparison of them and specimens of munda from along the north side of San Francisco Bay and Carquinez Straits with the type specimen of xanthogenys should determine the correct application of the name. For the present it seems best to retain the name munda and apply the name xanthogenys to the weasels inhabiting the northern part of the San Joaquin Valley and presumably the southern part of the Sacramento Valley. Efforts to obtain specimens of weasels from the Sacramento Valley have been in vain. A juvenal specimen taken five miles south of Fair Oaks, Sacramento County, by Mr. John Fitzgerald, Jr., in December, 1927, was examined at his home and found to agree in coloration with specimens from farther south. Geographically, this specimen probably is more nearly a topotype than any other examined. Most of the specimens examined are immature and adequate adult cranial material has not been seen. Two adults, one of each sex, from Los Banos have skulls of large size which agree with those of nigriauris. The same is true of one adult and one young female from 4 miles southwest of Turlock, which, unlike the animals from Los Banos, show a darkening of the head extending in reduced degree even to the inside of the ears, as in nigriauris. The slightly darker than average (for xanthogenys) color on the back may indicate intergradation with nevadensis. Intergradation with M. f. nevadensis is shown by specimens, from the southern part of the Sierra Nevada, mentioned in the account of nevadensis. None of the skulls shows malformation of the frontal sinuses such as result from infestation by parasites.
Mustela frenata nigriauris HallLong-tailed Weasel Plates 22, 23, 24, 34, 35, 36 and 41
Remarks.—Like M. f. latirostra, nigriauris long bore the name xanthogenys. The fairly adequate lot of specimens is divided between the collections of several institutions. The most satisfactory material in any one collection is in the Stanford University Natural History Museum where local specimens have been accumulated over a period of many years. No actual intergrade between nigriauris and xanthogenys has been seen, although the specimens from Los Banos, referred to xanthogenys, have large skulls as in nigriauris. Intergradation with latirostra is shown by specimens, referred to latirostra, from the Los Angeles area. Also the one adult male from 5 miles southeast of Santa Margarita, San Luis Obispo County, is of small size and in this respect approaches latirostra. The range of nigriauris is separated from that of munda by San Francisco Bay, Carquinez Straits, and I suppose by the lower part of the San Joaquin River. On the basis of color of the inside of the pinna of the ear, the two subspecies are uniformly distinct. Intergradation is assumed to occur through the subspecies xanthogenys. None of the 26 adult and subadult specimens examined for evidences of infestation of the frontal sinuses by parasites shows malformation of the sinuses.
Mustela frenata latirostra HallLong-tailed Weasel Plates 1, 22, 23, 24, 34, 35 and 36
The skull of the male of latirostra, compared with that of nigriauris, is by weight, more than one-fourth lighter, has a lesser basilar length, a lesser mastoid breadth, a lesser zygomatic breadth and a narrower M1. In these features no overlap has been observed between adults from the general vicinities of the type localities of the two forms. In adult males of latirostra the postorbital breadth, with one exception, is more than the combined length of P4 and P3 whereas the reverse is true in adult males of nigriauris. Both males and females of latirostra have a generally smaller skull with relatively broader interorbital and postorbital parts and the tympanic bullae are relatively larger, rounder and more inflated. Compared with the skull of the male of pulchra that of latirostra is, by weight, more than one-fourth lighter, has a lesser basilar and orbitonasal length, lesser zygomatic and mastoid breadth and a more nearly flat braincase. In these features no overlap has been observed between adults from the general vicinities of the type localities of the two subspecies. Also, in latirostra the tympanic bulla is longer than the rostrum whereas the opposite is true in pulchra. The skull of latirostra is generally smaller and relatively, on the average, has the preorbital part of the skull deeper and broader with longer tooth-rows, although with shorter rostrum, while the zygomatic and mastoid breadths are less. Study of skulls of subadult females of pulchra indicate that females of latirostra and pulchra differ in the same fashion as do males. Remarks.—This subspecies long has gone by the name M. xanthogenys and the type locality was generally supposed to be in the vicinity of San Diego. This supposition seems to have originated with Merriam's (1896:25) statement that the type locality was "Southern California, probably vicinity of San Diego." Nevertheless, as set forth in the account of M. f. xanthogenys the type specimen concerned now is thought to have come from much farther north. Although 76 Recent specimens are available from southern California, additional adults are needed to understand the geographic variation there. M. f. latirostra may be a composite—made up of more than one geographic race. Specimens from San Diego County differ so much in relative length of the tail that at one stage in the present study it was thought that a difference in this respect existed between the coastal animals and those from farther inland. Material received later did not wholly substantiate this view and because of the uniformly small size of all of the skulls from that county, the animals were later regarded as of the same subspecies. Eventually, even this supposed common feature proved to be inconstant for an adult male from Jamacha, no. 7098, of the San Diego Society of Natural History, and another adult male from San Marcos, no. 8869, collection of Ralph Ellis, were later examined and found to have skulls as large as those of average-sized, adult males of nigriauris. Despite these puzzling local variations, it is established that the long-tailed weasels of southern California are smaller than those from farther north. Also, the southern animal averages smaller in weight and size of skull, and the skull is differently proportioned. Specimens in series from Los Angeles County definitely are intermediate in size and shape of skull between latirostra from San Diego County and nigriauris from, say, Santa Clara County, but definitely more closely resemble latirostra from San Diego County than they do nigriauris. A skull of a young animal, not here identified to subspecies, from Potholes, in the Colorado River Valley, 10 miles northeast of Bard, Imperial County, California, may have closest relationship to M. f. latirostra. Additional comment on this specimen is offered in the account of M. f. neomexicana. From the asphalt pits of Rancho La Brea, in Los Angeles County, a total of 57 skulls have been examined, more than half of which are reasonably complete. I have been unable to learn whether these came from pits regarded by students of the deposit as wholly Recent, from pits regarded as of Pleistocene age, or from both. Suffice to say that only two specimens were found which could be distinguished from skulls of the subspecies of weasel living in that area today. These two specimens, lent to me by Professor Chester Stock, were with other skulls received from the Los Angeles Museum of History, Art and Science and bore identifying numbers as follows: 16/20-27, the anterior part of the skull of an adult, and 16, the skull posterior to the cribiform plate of a subadult or possibly young individual. The latter has a mastoid breadth of 28.0 millimeters, a tympanic bulla 16.1 long and other measurements in proportion. It is larger than any specimen of weasel, of any subspecies, seen from California and in the subgenus Mustela seems to be exceeded in size only by certain individuals of M. f. texensis. M. f. neomexicana attains relatively large size and comparisons were made with individuals of that subspecies. However, the young specimen from Rancho La Brea differs from neomexicana in that the tympanic bullae rise less steeply on the medial sides and the inferior lip of the external auditory meatus is less developed laterally. Age considered, the sagittal crest is less developed and the mastoid processes project more abruptly from the skull. The anterior part of the skull of the adult, no. 16/20-27 is larger than any specimen seen of M. f. latirostra or adjoining subspecies, and among California-taken specimens is equaled in size only by the largest males of M. f. munda from the northwest coastal district in Mendocino County. This adult from Rancho La Brea differs from neomexicana, sex and age taken into account, in greater postorbital breadth, lesser rostral width in comparison with the interorbital breadth, and in having the temporal ridges at the anterior end of the sagittal crest spread out into a Y-shaped, rather than a T-shaped, pattern. All these differences from neomexicana are features of agreement with the California bridled weasels of the subspecies latirostra, nigriauris, and munda. The same is true of the characters which set apart the young specimen from neomexicana. In summary: of 57 weasel skulls examined from the asphalt pits at Rancho La Brea, Los Angeles County, all but two are indistinguishable from the skulls of the Recent weasel living in that region today. These two skulls agree in qualitative characters with animals of the California coastal subspecies now living from Los Angeles northward to Humboldt County, but are larger. For the time being these two may be thought of as giants of the same type of animal inhabiting the Los Angeles region today. Only one of 41 adult and subadult skulls examined for malformation of the frontal sinuses shows infestation by parasites.
Mustela frenata pulchra HallLong-tailed Weasel
As compared with the skull of the type specimen of inyoensis, skulls of adult males of pulchra are larger throughout, relatively broader, especially in the preorbital part of the skull, have more inflated tympanic bullae, and are less convex in dorsal outline. Comparison of the skull with that of latirostra has been made in discussion of that subspecies. Comparison of skulls of adult males of nigriauris and pulchra shows that those of pulchra average larger in every measurement taken except those of m1, M1, P4, and depth of skull at posterior borders of upper molars. The basilar length is only slightly more and it follows that, relative to this length, other measurements of the skull are relatively, as well as actually, larger. In no one measurement is there an entire lack of overlap, but the skulls of adult males, and probably adult females, may be distinguished from those of nigriauris by the combination of the following mentioned, average differences: Tympanic bullae larger in each of three dimensions; preorbital and interorbital parts of skull broader and notably heavier; interorbital breadth greater; zygomatic arches more expanded laterally; mastoid processes more prominent. As compared with xanthogenys, differences of similar nature, but of greater degree, distinguish pulchra. As compared with those of nevadensis (represented by specimens from Mono Co., Calif.), skulls of adult males of pulchra average larger in every measurement taken and no overlap exists in basilar length, orbitonasal length, mastoid breadth, zygomatic breadth, length of tympanic bulla, or depth of skull at either the anterior margin of the basioccipital or at the posterior margins of the upper molars. Relatively, the preorbital portion is about the same size in the two forms. Remarks.—The best material of this big weasel was obtained in 1910 and 1911 by John Wimmer and forwarded to the California Academy of Sciences through John R. Rowley, although in 1905, one specimen had been obtained by A. S. Bunnell for the collections of the United States Bureau of Biological Survey, another by J. Grinnell for the Museum of Vertebrate ZoÖlogy in 1912, and in 1933, another by L. M. Huey, for the San Diego Society of Natural History. The males from the type locality are relatively uniform in size and shape of skull. The one exception is no. 137935, U. S. Nat. Mus., slightly younger than the others. Its skull is relatively more slender than any of the others and does not display several of the differential characters. The male, no. 127566, U. S. Nat. Mus., from Alila (= Earlimart) is intermediate in cranial features between pulchra and xanthogenys as known from specimens taken in the vicinity of Fresno. The skull of the female, no. 127565, from the same place, is too young to provide diagnostic characters. Since the skull of an adult female of topotypical pulchra is unknown, doubt attaches to the identification of the adult, female specimen, no. 115895, U. S. Nat. Mus., from Delano. It has a relatively broad skull in comparison with the adult female of xanthogenys from Los Banos. The adult female, no. 9998, San Diego Soc. Nat. Hist., from 2 mi. SW Simmler, shows approach to nigriauris in slightly reduced size. The skin alone from Coalinga, a male, taken on April 10, 1935, measures 462, 179, 47. The adult female, with crushed skull, from 4 miles east of Coalinga, measures 350, 129, 40. In size, these specimens agree better with pulchra than with xanthogenys. The skin alone from 3 miles south of Coalinga is unsexed and without external measurements. Skulls of adults from Coalinga are needed to permit of more positive identification of the subspecies found there. The female from 4 miles east of Coalinga, taken on February 21, 1936, is in process of molt on the underparts, and the longer hair which is near (20´) Naples Yellow contrasts strongly with the incoming shorter hair which is near (10 c) Salmon-Orange. The skin alone, no. 16270, Mus. Vert. ZoÖl., from Isabella, was made up from a decayed animal and is of but little use. It is referred to pulchra purely because of geographic nearness of Isabella to the type locality of pulchra. The most that can be told from the specimen is that it is a relatively light-colored, bridled weasel. The fact that the color is slightly darker than in pulchra may or may not indicate intergradation with nevadensis. No. 54103/41042, U. S. Nat. Mus., consisting of crushed bits of skull and the skin of the head, is from Willow Spring, Kern County. This marginal locality is really in the Mojave Desert rather than in the San Joaquin Valley. The light color of the skin of the head suggests pulchra, but it is realized that a complete specimen might show the animal there to be unlike pulchra. None of the skulls shows evidence of having had the frontal sinuses infested by parasites.
Mustela frenata inyoensis HallLong-tailed Weasel
Compared with the skull of the male of nevadensis, no single difference not covered by individual variation in nevadensis has been detected. Selected differences of inyoensis in comparison with latirostra are larger size, less inflated tympanic bullae and relative narrowness of the postorbital, interorbital and preorbital parts of the skull. Comparison of the skull with that of M. f. pulchra is made in the account of that subspecies. Remarks.—Although two specimens of this subspecies were taken during the Death Valley Survey conducted by Dr. C. Hart Merriam, only three additional individuals are known to have been saved as study specimens since that time. M. f. inyoensis as now known may be thought of as closely similar to M. f. nevadensis except for the presence of well-developed white facial markings like those found in the weasels of the San Joaquin Valley and coastal region of California south of San Francisco Bay. The nonwhite areas of the head are almost the same color as the back and not distinctly blackish as in M. f. latirostra and M. f. nigriauris. The one specimen in the winter coat, no. 25392/32805, U. S. Nat. Mus., from Lone Pine, is brown rather than white. The brown has the pale smoke-tinge common in the winter pelage of subspecies whose members are either brown or white in winter. The range of this subspecies is thought to include the floor and lower elevations of Owens Valley although it may occur in limited numbers southwestward along the base of the Sierra Nevada and through the mountains in places of low elevation like Walker Pass its range may meet that of pulchra. The type specimen was taken in an alfalfa field by ranch hands, who, according to A. C. Shelton (MS), stated that the species was common at the type locality. None of the five specimens shows infestation of the frontal sinuses by parasites.
Mustela frenata neomexicana (Barber and Cockerell)Long-tailed Weasel Plates 1, 22, 23, 24, 34, 35 and 36
As compared with the skull of the male of M. f. frenata, that of neomexicana is decidedly more angular and ridged. The postorbital constriction is narrower, the mastoid breadth greater (it is less than the postpalatal length in some subadult males), the sagittal crest much higher with impressions of the temporal and masseter muscles carried farther forward on the frontals, rostrum shorter and tympanic bullae wider and more inflated. Similar, though less marked, differences exist between the females. As compared with M. f. leucoparia and perotae, the same differences as noted above between frenata and neomexicana exist. In addition the tympanic bullae are so far removed from the foramen ovale that the distance from the anterior end of each bulla to the foramen ovale, instead of being less than the height of tympanic bullae, is in leucoparia more than four-fifths this height and in perotae more than the entire height. Also, in perotae, the squamosal, anterior to each tympanic bulla, is ventrally convex rather than ventrally concave as in neomexicana. Compared with M. f. longicauda, neomexicana is relatively narrower in the interorbital region, has relatively shorter tooth-rows, a V-shaped rather than a U-shaped interpterygoid space and in males has the interorbital region flat rather than convex and the sagittal crest is higher. The same differences are to be noted in comparison with nevadensis but here the difference in relative length of tooth-row is less. The same differences exist also in comparison with M. f. arizonensis except that its interorbital breadth, relative to the rest of the skull, is about the same. Difference in size is especially marked here; even females of neomexicana average larger than males of arizonensis. Remarks.—When Barber and Cockerell named this subspecies in 1898, they had three specimens. Only two others are known to have been taken before this time. These are a skeleton, without corresponding skin, taken at Lozier, Texas, in 1890 by Wm. Lloyd, and no. 21779/36482, U. S. Nat. Mus., taken on April 6, 1893, by R. D. Lusk at Tombstone, Arizona. On the back of a label recently attached to the last mentioned specimen the name C. K. Worthen appears and probably signifies that the specimen was purchased from this dealer in vertebrate specimens. M. f. neomexicana has a large geographic range. The old male from Liberal, Seward County, Kansas, extends the known range far to the northeast. Geographically, this occurrence is logical for the southwestern desertlike conditions extend to this part of Kansas. Probably the subspecies occurs in southeastern Colorado and in the panhandle of Oklahoma where conditions are similar. Bailey (1905:198) lists neomexicana as a member of the mammalian fauna of Texas. As stated by him (loc. cit.:198) this inclusion is based on geographic grounds and not on actual specimens. Strecker (1926:13) also includes neomexicana in his list of Texas mammals but writes me, under date of January 9, 1928, that "I included Mustela frenata neomexicana as a Texas mammal on the strength of its being mentioned by Bailey...." On better ground, Bailey (1928:97) lists the subspecies as occurring in southeastern New Mexico at Carlsbad Cavern. However, Bailey (loc. cit.) knew of the existence of weasels just below El Paso and at Langtry, Texas. An unsexed skeleton, no. 167891, in the United States National Museum, from Lozier, Texas, is not certainly identifiable to subspecies. If, as I think, the animal is a female, its skull is intermediate between that of frenata and neomexicana although when all features are considered it is seen to be nearest the latter. The large size (basilar length of 46.5 mm.) may reflect some relationship to texensis. The field notes of the collector furnished me by Dr. H. H. T. Jackson (MS), describe the color as brownish yellow above and sulphur below. The admission of this subspecies to the list of mammals of Texas is made certain by the female (no. 1572, Texas Cooperative Research Collection) taken on July 28, 1940, 1-1/2 mi. NW Kent, Texas, by C. E. Scull. The skull alone from Durango (City of), extends the known range far to the south. This skull is typical of neomexicana. Skins from the same place would be especially interesting as showing the approach, if any, in color, of neomexicana to M. f. leucoparia. Mr. D. D. Stone of Casa Grande, Arizona, writes, under date of February 2, 1927, that a weasel was seen by an acquaintance of his in a field near Chandler, Maricopa County, Arizona. Probably this was neomexicana. If so, its range extends much farther west than collected specimens show. Actual intergradation with M. f. frenata is not shown by the material at hand. The two females from Albuquerque, although typically neomexicana as regards color, have smaller, less prominently ridged skulls than females of neomexicana of the same age from farther south and approach M. f. nevadensis. Probably the geographic ranges of M. f. neomexicana and M. f. latirostra do not meet; the only evidence of the existence of weasels in all of the large area, comprising western Arizona and the deserts of eastern California, which intervenes between the ranges of the two subspecies is the skull of a young individual, no. 68842, Mus. Vert. ZoÖl., from 10 miles northeast of Bard, Imperial County, California. There, on December 29, 1932, Jack C. vonBloeker, Jr., retrieved the weathered skull with some of the vertebrae attached, from the top of a wood rat's nest beneath a mesquite tree near the west bank of the Colorado River. The idea that the carcass may have been washed down the river from far upstream gains no support from a comparison of the specimen itself for the tympanic bullae are larger than in nevadensis and the skull is larger than the largest males seen of arizonensis, the two upriver races. On the basis of size the skull could be either a male of latirostra or a female of neomexicana. These two subspecies, like arizonensis and the skull in question, have much inflated bullae. However, the immaturity of the specimen conceals any other diagnostic cranial features, and prevents referring it certainly to either neomexicana or latirostra. In any event the specimen provides no evidence of intergradation between the two forms last mentioned. Speculating on its identity, I should say that it might be either an intergrade between arizonensis and nevadensis, from southern Utah or northwestern Arizona, or a member of an unnamed race resident in the lower part of the valley of the Colorado River. Whereas M. f. panamensis and M. f. aureoventris are the darkest-colored weasels and occur in regions of heavy rainfall, M. f. neomexicana is the lightest-colored American weasel and occurs in an extremely arid region where the rainfall and humidity are slight. According to Barber and Cockerell (1898:189) "The type specimen was shot in the grass on the shore of Armstrong's Lake...." Bailey (1928:97) found the tracks of one of these animals "in the great pit at the west entrance to" Carlsbad Cavern and supposes they "hunt the cave walls for mice and other small game." Data on the label attached to no. 230973 states that the specimen was taken, two miles west of Willcox, Arizona, in a prairie dog town. Only two of the 23 skulls show evidence of infestation of the frontal sinuses by parasites.
Mustela frenata texensis HallLong-tailed Weasel
Remarks.—The type specimen, taken by the veteran collector of Texan mammals, H. P. Attwater, appears to have been the first one of these animals to find its way into the collection of any museum or naturalist. The second specimen from Kerr County was secured by, or through, the well-known commercial collector, F. B. Armstrong. Two trade skins, from Kerr County, taken on December 10, 1938, are in the Texas Cooperative Research Collection, as is also the skeleton of a young animal from Fredericksburg. The two other specimens from McLennan County (both males contrary to the statement of Strecker, 1924:14), owe their preservation to the alertness of John K. Strecker, Curator of the Baylor University Museum, who has given a complete account of their history. The range of this subspecies is thought to include much of central Texas. The preserved parts of the skin of the type specimen show it to have been generally large. The part of the tail preserved measures 226 millimeters and the skin of the head and neck is correspondingly large. The skin alone, no. 427, from near Waco, Texas, has, as now stuffed, a body 365 millimeters long. Individuals of this race attain larger size than those of any other American member of the subgenus Mustela with the possible exception of Mustela frenata macrophonius from Veracruz, MÉxico. In addition to large size, texensis and macrophonius are analogous in that each has a small geographic range at the northern end of an extensive range of its similarly colored southern relative from which it differs mainly in size. Each of the two groups, goldmani and macrophonius on the one hand and perotae, frenata and texensis on the other, has relatively uniform color, color pattern and body proportions over a large region but at its northern extremity develops a "giant" population, M. f. macrophonius and M. f. texensis, respectively. The skull of the type specimen of M. f. texensis is the largest one seen of any American weasel. The type specimen of M. f. macrophonius has a basilar length that is greater by one-tenth of a millimeter but in every other measurement taken the skull of M. f. texensis is the larger. Its weight, 8 grams, also shows it to be larger. The broad, white bands in front of the ears are confluent with the white patch between the eyes on both sides in two specimens and on one side only in one other specimen. A white patch between the ears is present in four specimens. The dark spot at each angle of the mouth is absent on both sides in four specimens and on one side only in one other specimen. Thus out of a possible twelve cases, the broad bands in front of the ears are confluent with the spot between the eyes in five cases. Four of the six specimens have a white spot between the ears. The dark spot at each angle of the mouth is present three out of a possible twelve times. The skull of no. 2017, from five miles north of Waco, is smaller than either of the two skulls seen from Kerr County and in this respect approaches M. f. frenata. There is no actual evidence of intergradation with any other subspecies but intergradation probably does take place with M. f. neomexicana and possibly with M. f. arthuri and M. f. primulina. Strecker (1924:14) remarks that of the two specimens obtained near Waco, one was taken in a trap baited for mink and the other was shot in a hen house. None of the four skulls had the frontal sinuses infested with parasites. Mustela frenata frenata LichtensteinLong-tailed Weasel Plates 1, 22, 23, 24, 36, 37, 38 and 40
Comparison of the skull with those of M. f. arthuri, tropicalis, perotae, leucoparia and neomexicana has been made in accounts of those subspecies. As compared with M. f. texensis (known only from males), the only difference detected is smaller size. Remarks.—As Merriam (1896:27) has said: "In 1813 a Russian naturalist, Sevastianoff, gave the name 'Mustela brasiliensis' to a weasel brought to St. Petersburg by Capt. A. J. Krusenstern on his return from a voyage around the world. The animal was said to have come from Brazil, but no definite locality was given." This name was long applied by many European naturalists to American weasels which had white facial markings, and several American naturalists adopted the name. However, Lichtenstein in 1832 applied the name Mustela frenata to the weasels of the vicinity of MÉxico City and that name was used for bridled weasels from MÉxico and the southwestern United States by most subsequent German writers and by several Americans. In 1896 Merriam (1896:27) showed that Sevastianoff's Mustela brasiliensis, 1813, although probably the same as Mustela frenata, was preoccupied by Gmelin's Mustela brasiliensis, 1788, applied to an otter and that Lichtenstein's name must be used as the next available one. Since that time, 1896, frenata has been the name applied to the large bridled-weasels of Texas and the high table land of MÉxico south to MÉxico City. It may be added that in 1937 search by the writer among the specimens and records at the Russian Academy of Sciences, in Leningrad, failed to reveal any trace of the type specimen of Sevastianoff's Mustela brasiliensis. The geographic range of this subspecies is relatively large and, as might therefore be expected, specimens show geographic variation. The specimens from Tlalpam, which Merriam (op. cit.:27) regards as topotypes, differ in certain respects from specimens from Texas. The skull of the adult male "topotype," no. 50826, differs from any other adult male seen in that the basilar length, the length of the upper tooth-rows, the orbitonasal length, the ratio of the same to the basilar length, the mastoidal breadth, the zygomatic breadth, the depth of the skull at the posterior margins of the upper molars, and the length and breadth of M1, are greater. The height of the tympanic bullae is less than the average height for these structures in more northern specimens. The specimens from Tlalpam have also larger external measurements than the average of more northern specimens. All of these features show an approach to the subspecies of more southern distribution. On the other hand, the blackish of the head is not more intense or more extended posteriorly onto the neck than in specimens from Brownsville, Texas. The skin, with skull crushed, no. 767, in the Paris Museum, from 3200 meters elevation near Toluca, does have the black color of the head extended 30 millimeters posteriorly to the ears. In this feature, and also in the extensively white face on which the white bar in front of each ear connects with the frontal spot, as well as with the color of the underparts, the specimen resembles leucoparia. Better material from the western part of the state of MÉxico may show the range of leucoparia to extend eastward almost or quite to Toluca. An adult male, taken on July 15 at Miquihuana, Tamaulipas, is unique in several respects. The top of its head is black, rather than blackish, and this color extends posteriorly on the top and sides of the neck almost halfway to the shoulders. All of the upper parts are much more darkly colored than in other specimens of this race. The least width of the color of the underparts is 63 per cent of the greatest width of the color of the upper parts; thus the color of the underparts is considerably more extensive than in any other specimen seen. The underparts are more intensely colored than in the average specimen. The mastoidal breadth is greater than in any other adult male and amounts to more than the postpalatal length. On available maps the elevation of Miquihuana is given as 1892 meters (about 6200 feet). Thus the dark colors can hardly be ascribed to more tropical conditions than those under which animals from Brownsville, Texas, live. Brownsville is only a few feet above sea level and only 235 miles farther north. The difference noted, therefore, seems to be of geographic significance. However, there is from Alvarez, San Luis PotosÍ, approximately 115 miles south of Miquihuana, a young (nearly subadult) female, no. 21968, which is as light colored as specimens from Brownsville, Texas, or Tlalpam, MÉxico. The only distinctive feature of this specimen is the much greater extent of its white facial markings; they are more extensive even than in the specimen from Miquihuana. Finally, the series from Brownsville, Texas, indicates that the animal there is smaller than frenata from the vicinity of MÉxico (city). The skull is similarly proportioned except that relative to the basilar length the orbitonasal length is more. Several other measurements of the skull of the adult male from Tlalpam, as pointed out above, are actually, although not relatively, greater than in any specimen from Brownsville. The similarities between specimens from the two localities, Tlalpam and Brownsville, are striking; since the two localities lie at opposite, extreme ends of the range more geographic variation would be expected. All that is known of the characters of populations from intermediate localities is that the one specimen from Alvarez shows no peculiarities whereas the one from Miquihuana suggests the existence there of a geographic variant. None of the specimens seen shows actual intergradation with M. f. neomexicana or with M. f. arthuri but it is supposed that frenata intergrades with each of these subspecies. The difference between frenata and arthuri is greater than between frenata and neomexicana. Bailey (1905:198) records tracks of a weasel seen just below El Paso which he supposed had been made by a weasel of the neomexicana type. He also cited the taking of a weasel at Langtry which suggested to him (op. cit.) "... a continuous range from the country of frenatus up the Rio Grande to the type locality of neomexicanus at Mesilla Valley," New Mexico. Other records of occurrence in Texas cited by Bailey, in addition to those provided by specimens examined by the writer, are San Diego, Beeville, and Port Lavaca. The Port Lavaca record is the easternmost one assigned to the subspecies frenata; possibly specimens from there would be referable to arthuri. The series of thirty-four specimens from Brownsville, Texas, permits measuring the amount of individual and age variation in several features. For instance, the material is sufficient to show that external measurements of subadults and those that fall in the upper part of the category designated as "young" may be included with the measurements of adults, because the mentioned measurements are not appreciably greater in adults. The series of skulls, although not providing more than six of any one age, shows the range of variation in size and proportion of certain parts and enables the student the better to evaluate cranial characters of nearby races known from only a few specimens. For example, not one of the twenty skulls of males from Brownsville and immediate vicinity is as large as either of the two specimens of texensis from Kerr County. The white facial markings vary much in size and shape. In the series of thirty-four skins from Brownsville the broad white bands in front of the ears are confluent with the white patch between the eyes on both sides in three specimens and on one side only in six other specimens. These bands are confluent with the color of the underparts in all but two specimens. In one specimen the connection is lacking on both sides and in the other on one side only. A white patch between the ears is present in two specimens. The dark spot at each angle of the mouth is absent on both sides in eleven specimens and absent on one side only in ten others. In six other specimens from parts of Texas north of Brownsville, the broad white bands in front of the ears are confluent with the white patch between the eyes on both sides in one specimen. A white spot between the ears is present in one specimen. The dark spot at each angle of the mouth is absent on both sides in six specimens and on one side only in three other specimens. In eleven specimens from MÉxico, the broad white bands in front of the ears are confluent with the white spot between the eyes on both sides in two specimens and on one side only in one other specimen. The white spot between the ears is present in one specimen. The dark spot at each angle of the mouth is absent on both sides, in six specimens, and on one side only in one other specimen. Thus, in 51 specimens the broad bands (one in front of each ear) are confluent with the white patch between the eyes in nineteen out of 100 instances, and not with the color of the underparts in three instances. A white spot between the ears is present in four specimens. The dark spot at each angle of the mouth is present 47 out of a possible 98 times. Four juvenal specimens from Brownsville, Texas, with their dates of capture and probable age, are as follows: no. 58574, ?, three weeks old, taken on February 15; no. 17318/24239, ?, four weeks old, taken on March 16; no. 45899, ?, forty days old, taken on May 21; no. 21778/36481, ?, thirty days old, taken on October 20. In the order given, the dates of birth of these four juveniles would be approximately as follows: January 25, February 15, April 1, and September 20. The dates of birth of other specimens less than three months old as judged by the stage of development of the skull, and reckoning backward from the dates of capture, are as follows: April 1, April 30, May 25, October 12, and December 21. Thus, young appear to be brought forth at Brownsville, Texas, in the fall, winter and spring, that is to say from the latter part of September until the latter part of May. Mustela frenata frenata is either free of the parasites that infest the frontal sinuses of most weasels, or withstands their presence remarkably well, for only one skull shows a definite pathological condition of the frontal sinuses. Allen (1896:74) quotes H. P. Attwater, with respect to this species in Bexar County, Texas, as follows: "Not common, but occasionally met within the chaparral and cactus lands, where Wood Rats, Rabbits and Quail abound. They were frequently met with around San Antonio during the great 'Tramp Rat' [= Sigmodon hispidus texianus, see Bailey (1905:116)] invasion of 1889-90."
Mustela frenata leucoparia (Merriam)Long-tailed Weasel Plates 1, 24, 25, 26, 29, 30, 36, 37 and 38
Comparison of the skull with those of M. f. perotae, goldmani and neomexicana has been made in the accounts of those subspecies. As compared with that of frenata the main difference is the less inflated tympanic bulla, the height of which is approximately equal to, rather than decidedly more than, distance from its anterior margin to foramen ovale. Remarks.—The first specimen known to have been preserved is the alcoholic in the British Museum of Natural History, taken in September, 1891, on the RÍo Santiago in Jalisco, by D. A. C. Buller. The other known specimens of this white-faced weasel are divided between the American Museum and the United States National Museum. The two referred specimens from Jalisco were the last of several helpful ones collected in MÉxico and Central America by J. H. Batty, and these two were taken less than three months before Batty's tragic death in Chiapas (see Allen, J. A., 1906:191). The five specimens from MichoacÁn were taken by Nelson or Nelson and Goldman together. Merriam had only three of these when he named the subspecies and remarked (1896:29) that "This form is the poorest subspecies described in the present paper." Although the form is not strongly marked, the two additional specimens from MichoacÁn and better comparative material than Merriam had confirm several of the differential characters ascribed to it by him and indicate the existence of still other characters. M. f. leucoparia occurs in the Sonoran and Transition life-zones. No. 27258 from Los Masos, and no. 26153 from Artenkiki (see specimens examined for other spellings) approach true frenata in coloration. Each of these specimens has a few white hairs between the ears and the white patch between the eyes is confluent on one side only with the lateral white bands on the side of the head. No. 27258 from Los Masos has a dark spot at each angle of the mouth. The 7 other specimens are relatively uniform in coloration. Each has the white spot between the eyes confluent on both sides with the extensive white areas on each side of the face. None has a dark spot at either angle of the mouth. Of these 7 specimens, the type specimen and three others have white hairs forming a median line between the ears and a fifth specimen has a white spot behind each ear. M. f. leucoparia is most like M. f. frenata. Unlike frenata, leucoparia has tympanic bullae that are less inflated, narrower and less projected, at their anterior margins, from the cranium. In these characters leucoparia is intermediate between M. f. frenata and M. f. goldmani. The latter subspecies has the least inflated, narrowest and least projecting tympanic bullae of the three. The black color of the head extends, on the average, farther posteriorly than in M. f. frenata but not so far as in M. f. goldmani. The general color, too, is intermediate between that of M. f. frenata and that of the much darker M. f. goldmani. The white facial markings are more extensive than in either M. f. frenata or M. f. goldmani. This applies to both the white area between the eyes and the one on each side of the head between the ear and eye. M. f. neomexicana, whose range possibly meets that of M. f. leucoparia, also has more extensive white facial markings than M. f. frenata but less extensive markings than M. f. leucoparia. On the basis of skulls alone, specimens of frenata from Tlalpam and those of leucoparia from Los Reyes can hardly be distinguished. This fact, and the circumstance that the specimens from the northern part of the range of leucoparia closely resemble frenata in color, constitute sufficient evidence for regarding the two as only subspecifically distinct. The female, no. 26153 from Artenkiki, as mentioned above, approaches true frenata in coloration. On this account it is not to be regarded as typical and it was because no other skulls of adult females were available that this one was used for comparison with females of allied races. M. f. leucoparia is, then, a subspecies of the large, temperate-zone group and is unique in possessing the maximum extent of white facial markings. None of the seven skulls shows signs of having had the frontal sinuses infested with parasites.
Mustela frenata perotae HallLong-tailed Weasel
Comparison of the skull with that of M. f. tropicalis is made in the account of that subspecies. Compared with the skull of M. f. macrophonius, that of the female of perotae is more flattened, has the longitudinal dorsal outline distinctly concave rather than flat just behind the postorbital processes, and much wider tympanic bullae. Accordingly, the basioccipital is slightly narrower in perotae. The more marked postorbital constriction of the type specimen of perotae possibly is due to its relatively greater age. As compared with the skull of M. f. leucoparia, that of the female of perotae has less inflated tympanic bullae, the height of each being half as great as distance from its anterior margin to foramen ovale, whereas, in leucoparia (as represented by no. 26153) the two distances are equal. As compared with that of M. f. frenata, the skull of the female of perotae differs mainly in the lesser inflation of the tympanic bullae and their relative position. The height of each bulla is in perotae only half as much as, but in frenata more than, the distance from its anterior margin to foramen ovale. The anterior margin of the bulla is much less projected from the floor of the braincase in perotae. The squamosal anterior to each bulla is convex ventrally in perotae but flat or concave ventrally in frenata. Remarks.—The type specimen and a juvenal female from the town of Perote were taken in the spring of 1893 by E. W. Nelson. Of these two, the type specimen was mentioned and figured by Merriam (1898:30, fig. 16 [= fig. 15], pl. 3, fig. 2) as Putorius frenatus. The referred nontypical specimen from Cerro San Felipe, Oaxaca, was referred by Merriam (op. cit.:29) to Putorius frenatus goldmani with the comment that it was intermediate "... both in coloration and cranial characters, between typical frenatus and goldmani;...." No other published references to this subspecies, or specimens of it, have been seen. In 1941 and 1942, W. B. Davis and associates took four specimens along the boundary between the states of Puebla and MÉxico. Although the specimen from Cerro San Felipe, Oaxaca, is referred to Mustela frenata perotae, to the description of which it answers best, that specimen, on account of its structural characters and geographic position relative to adjacent races, is in reality an intergrade between several of the adjacent races. Some of its intermediate characters are pointed out in the discussion of M. f. goldmani. In the specimens from 45 and 55 kilometers ESE of MÉxico (city) the black color of the top of the head does not extend so far behind the ears as in the holotype of M. f. perotae and in this feature the two specimens show intergradation between the two subspecies, perotae and frenata. The type specimen taken on May 26, is acquiring new hair on the belly and lower sides which appears to be the result of a normal molt. As would be expected from its geographic position, M. f. perotae resembles M. f. frenata of northern MÉxico and the high mountain forms of southern MÉxico more than it does the lowland tropical forms. This is true as regards size of entire animal, proportions of its parts, and size, general angularity and major proportions of its skull. The marked postorbital constriction, convex supralacrymal face of rostrum, width of tympanic bullae and angularity of the braincase place it nearest M. f. frenata as does also the color and color pattern. The ventrally convex squamosal anterior to each tympanic bulla and the slight degree of projection from the cranium of the anterior margin of each tympanic bulla are intermediate in degree between the condition in M. f. macrophonius and that in M. f. frenata. Thus M. f. perotae combines several characters of M. f. frenata on the one hand with some of M. f. macrophonius on the other and in some features, for instance in the size, shape and degree of inflation of the tympanic bullae, presents intermediate stages of development. On the eastern plain below the high mountain, Cofre de Perote, there ranges the similarly colored, smaller, tropical weasel, Mustela frenata tropicalis. Between M. f. perotae and M. f. tropicalis there is marked differentiation in the skulls with much less differentiation in coloration. The differences in typical skulls of the two subspecies are so pronounced that one would, at first glance, hardly believe it possible for direct intergradation to occur between them on the sides of this mountain. Merriam (1896:30) thought that it did not. The two skulls figured by him (op. cit.:31) are a topotype of M. f. tropicalis from Jico and the one which now is the type specimen of M. f. perotae. They show the great difference in size and proportions and are females of comparable ages, not of different ages as I suspected before examining the skulls. However, despite this marked difference in the skulls, there is some, although not conclusive, evidence of intergradation furnished by a young female from Xuchil, Veracruz. This specimen is described in connection with M. f. tropicalis (see page 366). None of the seven skulls shows marked deformity of the interorbital region, but two of the three adults appear to have had these parts infested with nematodes.
Mustela frenata goldmani (Merriam)Long-tailed Weasel
Comparison of male skull with that of M. f. perda made in discussion of that form. Comparison with that of M. f. nicaraguae shows similar differences, some of which are more pronounced. For example, squamosals anterior to tympanic bullae more convex ventrally and these bullae project less from braincase than in M. f. perda; thus the difference in these features is greater between goldmani and nicaraguae than between goldmani and perda. As compared with the skull of the male of M. f. macrophonius, each one of the skulls of the adult males of M. f. goldmani is smaller in every measurement taken, with two exceptions. The width of the tympanic bullae was more in three specimens of M. f. goldmani as was also the depth of the same in three specimens. Relative to the basilar length all but two of these measurements average less in goldmani; the exceptions are the zygomatic breadth and depth of the skull at the anterior margin of the tympanic bullae which average more. Relative to the basilar length, the orbitonasal length and depth of the skull at the posterior margin of M1 are less in each skull of goldmani. Thus, excepting the width and height of the tympanic bullae and the relative zygomatic breadth and relative depth of the braincase posteriorly, the skull of goldmani is shorter and relatively as well as actually narrower and lighter throughout. As compared with the skull of the male of M. f. leucoparia, that of M. f. goldmani averages a trifle shorter and no skull of goldmani equals that of leucoparia in actual or relative zygomatic and mastoid breadths or length or height of tympanic bullae. In depth, the skull of goldmani averages actually and relatively greater. Its teeth are smaller. The squamosal anterior to each tympanic bulla is convex ventrally whereas it is concave ventrally in leucoparia as in frenata. Remarks.—When Merriam (1896:28) named this subspecies, he had only one specimen but he called attention to the more important diagnostic characters, which additional specimens show pertain to the race as a whole. M. f. goldmani in typical form occurs in high mountains of the Upper Tropical Life-zone and is most closely related to M. f. frenata and M. f. macrophonius. The altitude at which the two specimens were taken, twenty miles southeast of Teopisca in Chiapas, is not known. Merriam (1896:28) states that the type specimen was obtained at "about 8200 feet." The specimen taken by Stirton in Salvador comes from 8000 feet and the one obtained by Barber in Guatemala from 9500 feet. The specimen from DueÑas, the skin alone of a young animal, is not instructive. As regards size, goldmani is larger than the immediately adjacent subspecies from the Lower Tropical Life-zone but is smaller than M. f. leucoparia or macrophonius. As compared with M. f. frenata, goldmani is longer, has an actually as well as relatively shorter tail, and a much longer hind foot. The most outstanding difference in externals from frenata is the naked foot soles. Molting probably takes place twice each year although actual proof of this is lacking. In number 133254 from twenty miles southeast of Teopisca, taken on May 12, the molt is well advanced. Another specimen from the same place still retains the winter coat. In color, goldmani is much darker than frenata, has less extensive white facial markings, longer black tip on tail, more restricted color of underparts, and lacks the extension of color of the underparts onto the hind feet. Of the adult males from the high mountains, the type specimen from Chiapas is lightest, and the one from Salvador is darkest. This progressively darker color to the southward probably is geographic variation. In total length and relative and actual length of tail, the specimen from Salvador is the smallest of the five adult males from the higher mountains. In addition to its darker color and smaller size, no. 12523 from Salvador shows certain distinctive cranial characters. The zygomatic breadth is less than, rather than more than, or equal to, the distance between the condylar foramen and M1 or than that between the anterior palatine foramen and the anterior margin of the tympanic bulla. This difference appears to be correlated with geographic position, since no. 15953 from Guatemala has the three distances about equal and therefore is intermediate in this respect between the specimen from Salvador and those from Chiapas, in which the zygomatic breadth is greater than the other two measurements. Also in the greater depth of the skull and smaller size of the teeth, this specimen from Salvador approaches the subspecies of the Lower Tropical Life-zone. It has, however, the longest, highest and widest tympanic bullae of any of the five specimens. The amount of ventral convexity of the squamosal in front of each tympanic bulla appears not to be greater than in the other specimens. As indicative of intergradation with perotae, leucoparia and possibly frenata, there is the specimen from Cerro San Felipe, Oaxaca. The degree of restriction of the color of the underparts is intermediate between that of goldmani and leucoparia. The same is true as regards the amount of projection from the braincase of the anterior margins of the tympanic bullae. The squamosal immediately anterior to each tympanic bulla is flat instead of ventrally convex as in goldmani or ventrally concave as in leucoparia and frenata. In accordance with the custom adopted in this paper of referring every specimen to some one subspecies, this specimen from Cerro San Felipe is referred to Mustela frenata perotae, to the description of which it most nearly answers. Possibly goldmani, as here constituted, is a composite form. The specimens from the high mountains closely resemble one another. However, a specimen, no. 68541 from "Finca El Cipres," Guatemala, which place Mr. G. Goodwin tells me is at an elevation of 2500 feet, approximately 5 miles north of Retalhuleu, has a basilar length of 47.3 and is correspondingly small in other parts. This suggests the existence of a small, lowland race on the western side of the central divide corresponding to perda and tropicalis on the eastern side. From only a few miles away, at San Sebastian, there is available, the adult skull of a still smaller animal. This skull only, no. 41026, in the Berlin Zoological Museum, has a basilar length of 46.1, zygomatic breadth of 27.4, and other cranial measurements notably smaller than those of specimens from the high mountains. A skin-only, no. 12038, collection of Donald R. Dickey, from La Cebia, altitude 2150 feet, near the city of San Salvador, seemingly represents an animal smaller than typical goldmani. This specimen from La Cebia has the light color of the underparts extended distally on the hind legs to the tips of the toes as in M. f. tropicalis. However, the upper parts are darker and resemble those of M. f. goldmani. A fourth specimen from only 3500 feet elevation, on the south side of Volcano Tajumulco, Guatemala, no. 41768, Field Museum of Natural History, a subadult male, measures only 490 in total length and has the least color of the underparts so restricted as to amount to only 22 per cent of the greatest width of the color of the upper parts. Both these features are suggestive of the lowland races. These four specimens indicate that the lowland population on the western side of the divide is smaller than the mountain population. The juvenile from Carolina and a young male from Finca Cipres, however, both closely resemble individuals of goldmani from the higher mountains. All these animals here are referred to goldmani. More specimens may reveal an amount and a pattern of geographic variation in weasels of this region that will require application of another subspecific name. The female, no. 68540, from Puebla agrees remarkably well with the skull of the female, no. 132528, of macrophonius. Differences displayed by the specimen from Puebla are its slightly narrower braincase and longer space between the foramen ovale and anterior end of the tympanic bulla. Considering the far eastern location of Puebla (just north of RÍo Motagua, at 89° W, according to a sketch map provided by Mr. G. G. Goodwin), this specimen might be expected to show some approach to the small lowland races. Actually, however, it displays the characters of goldmani better than does the subadult female from Volcano San Lucas, which is nearer the metropolis of goldmani, and I assume at a higher elevation than Puebla. Concerning this weasel Merriam (1896:29) says: "Mr. E. W. Nelson writes me that this fine weasel is found sparingly in the forest about Pinabete, Chiapas, at an altitude of 7000 to 8000 feet (2100 to 2500 meters). The type specimen was shot in the afternoon while hunting on a heavily wooded hill slope. It was heard making long, slow leaps over the dry, crisp leaves. Coming to a log, it stood up and rested its fore feet on the log, in which position it was shot by Mr. Goldman." The specimen taken by R. A. Stirton in Salvador comes from an elevation of 8000 feet in the rain forest of the Upper Tropical Life-zone. Mr. Stirton tells me that one morning on visiting his traps set for small rodents, he found in one the partly eaten remains of a Heteromys. Leaving these remains as found he placed a steel trap beside them and on the following morning found the male weasel in the trap. At least three of the ten specimens had the frontal sinuses infested with parasites.
Mustela frenata macrophonius (Elliot)Long-tailed Weasel Plates 24, 25, 26, 30, 37, 38 and 39
Comparison of the skull with that of M. f. goldmani is made in the account of that subspecies. Similar differences probably exist between males of perotae and macrophonius. As compared with skulls of males of M. f. tropicalis and perda, the skull of the male of macrophonius is larger in every measurement taken. The postorbital constriction is less, rather than more, than the combined length of the upper premolars. Relative to the basilar length, the following measurements are less than in any specimen of tropicalis or perda: length of tooth-rows; orbitonasal length; depth of skull at posterior border of upper molars; and depth of skull at anterior margin of basioccipital. Remarks.—This large weasel appears to have escaped the notice of naturalists until the spring of 1903 when J. Friesser obtained an adult female and juvenal male at PÉrez for the collection of the United States Bureau of Biological Survey. These specimens were tentatively referred to Mustela tropicalis. In the following January, Edmund Heller and Charles M. Barber obtained the adult male that was made the type specimen by Elliot who did not see, or if he did, did not mention, the specimens from PÉrez. He did, however, refer a young female from Xuchil, Veracruz, to his Putorius macrophonius. This young female is here referred to Mustela frenata tropicalis. The extent of the geographic range of this subspecies is not well known. Mustela frenata macrophonius and M. f. texensis are the largest American weasels. The basilar length in the type specimen is greater by one-tenth of a millimeter than in the type specimen of M. f. texensis. The other cranial measurements taken are greater in M. f. texensis. The skull of the female from PÉrez is one of the largest skulls examined of that sex. The juvenal male has teeth as large as those of the type specimen and the skull is the largest for its age of any seen. Although the skin of the female is understuffed and hence does not provide reliable measurements, it shows that the female is also large. The white bands in front of the ears are confluent with the white patch between the eyes on one side only in one specimen. It is the juvenal male. These bands are not confluent with the color of the underparts on either side in the female and on one side only in the adult male. None of the specimens has a white patch between the ears. The dark spot at each angle of the mouth is present only in the juvenile where it occurs on each side. Of the three specimens, the juvenile is the darkest and the adult male the lightest. The white facial markings are most extensive in the juvenal male and the least extensive in the adult female. M. f. macrophonius most closely resembles M. f. goldmani but in the relatively flattened braincase, deep constriction of the postorbital region and general angularity of the skull approaches M. f. perotae and M. f. frenata. Only one of the three skulls, that of the female, shows evidence of infestation of the frontal sinuses by parasites, and this did not result in malformation of the interorbital region.
Mustela frenata tropicalis (Merriam)Long-tailed Weasel Plates 25, 26, 27, 30, 37, 38 and 39
Comparison of the skulls of males and females with those of M. f. perda, the nearest relative, has been made in the discussion of that subspecies. Some of the features that readily distinguish skulls of M. f. tropicalis from those of M. f. frenata, perotae and macrophonius are as follows: Weight less than 4.8 grams; basilar length less than 48; postorbital breadth more than length of upper M-Pm tooth-row. The skulls of male frenata, perotae and macrophonius are much larger, heavier, and are decidedly more angular with more constricted postorbital region the least width of which is less than the length of the upper premolars. In frenata the anterior margins of the tympanic bullae are protruded much farther from the braincase. The skull of the female of M. f. tropicalis is smaller, weighing less than 3 grams; basilar length less than 41; postorbital breadth more than length of upper molar and premolar tooth-row. Remarks.—This subspecies was originally described by Merriam as a full species. Later he described Putorius tropicalis perdus as another subspecies. Allen (1916) placed P. t. perdus in synonymy but named Mustela tropicalis nicaraguae as new. In the present paper all three forms are recognized but are regarded as only subspecifically distinct from the other bridled weasels of MÉxico and Central America. The limits of the geographic range of tropicalis are fairly well known on the south and west but the only specimen available from the tropical coastal region north of Jico, is a young female from a point 50 miles south of Victoria. Thus, how far north along the coast it ranges toward Matamoros, where M. f. frenata occurs, is not known. The three specimens from Jico, a young female from Jalapa and another adult collected by J. Potts and labeled as coming from MÉxico City, are assumed to be typical. The latter specimen certainly came from an elevation lower than that of MÉxico City because M. f. frenata occurs there. Although the female from Jalapa, agrees well with specimens from Jico, a male, no. 12764/11058, from Jalapa, has a relatively broader skull, as in perda, although the tympanic bullae are short as in tropicalis. The resemblances to perda in features of coloration are: slightly darker upper parts, and the termination just below the knees of the color of the underparts. There are three specimens labeled as from Orizaba that indicate intergradation with perotae as does also the coloration of the juvenal female from 5 kilometers north of Jalapa. The specimens labeled as from Orizaba are old, poorly-prepared skins, only two of which have partial skulls. The size and coloration of the skins suggest perotae as do also the partial skulls in some respects although the skulls show greater resemblance to those of tropicalis. The topotype, female, no. 54993, was figured by Merriam (1896, fig. 16, p. 31) along with that of what now is the type specimen of M. f. perotae. Merriam called attention to the great difference in size between the skulls of the two sexes of M. f. tropicalis and compared the condition to that found in noveboracensis. Although the skull of the female from Jico is fully adult, it probably is exceptionally small. The young female from Xuchil is indistinguishable in coloration from the juvenal female of M. f. perotae from Perote, but in size of skull and size of teeth is intermediate between the female of tropicalis from Jalapa and the females from Cofre de Perote. There is then, indication of intergradation with M. f. perotae as well as with M. f. perda. M. f. tropicalis differs from M. f. perotae and M. f. frenata in about the same way that M. f. perda differs from M. f. goldmani and M. f. macrophonius. M. f. tropicalis and perda each is smaller and more intensely colored than goldmani and macrophonius, and inhabits the lowland to the east of their highland relative. At least five of the nine skulls have the frontal sinuses infested by parasites.
Mustela frenata perda (Merriam)Long-tailed Weasel Plates 25, 26, 27, 30, 37, 38 and 39
Comparison of the skull of the male with that of M. f. nicaraguae has been made in the account of that subspecies. The skull of the male as compared with that of M. f. tropicalis has shorter tympanic bullae, deeper braincase at anterior margin of basioccipital, lesser zygomatic and palatal breadth and smaller P4 and m1. The skull of the female is larger in every measurement taken except those reflecting width of the preorbital portion. This part is actually narrower but probably mainly because the females of perda are younger than those of tropicalis. Features in which three skulls of subadults of M. f. perda differ from the five adults of M. f. goldmani and show no overlap are: lesser basilar length, lesser weight, greater relative length of upper tooth-rows, greater relative width of rostrum, greater relative length of rostrum, lesser mastoid and zygomatic breadths, lesser width, length and height of tympanic bullae; lesser outside length of P4 and greater relative depth of braincase at anterior margin of basioccipital and at posterior margin of M1. Features in which perda averages less are: length of tooth-rows, interorbital breadth, orbitonasal length, relative zygomatic breadth, length of m1, outside and inside lengths of P4, width and length of M1, and depth of skull at posterior margin of M1. Features in which perda averages more than goldmani are: relative interorbital breadth, relative mastoid breadth and depth of skull at anterior margin of basioccipital. The length of the inner half of M1 averages the same. As compared with goldmani, the skull of the male of perda is shorter, otherwise generally smaller, but relatively broader except across the zygomatic arches, and relatively deeper. The anterior margins of the tympanic bullae project slightly less from the braincase and the squamosals immediately in front of these bullae are slightly more convex ventrally. Remarks.—Described by Merriam in 1902 as a subspecies of Putorius tropicalis, the form perda was regarded by Allen (1916:99) as not subspecifically distinct from P. t. tropicalis. This is the eastern, lowland subspecies of the Tropical Life-zone, corresponding to M. f. goldmani of the higher mountains just as M. f. tropicalis corresponds to M. f. frenata and perotae of the high mountains and table land. The difference in size between perda and nicaraguae and between perda and tropicalis is slight. M. f. perda is slightly less richly colored than M. f. nicaraguae but has the color of the underparts more restricted and has a longer black tip on the tail. In these respects it is second only to M. f. panamensis among Central American weasels. Evidence of intergradation with goldmani is furnished by the specimens from CobÁn, Guatemala, and the nearby locality San CristÓbal in Verapaz, Guatemala. Reduced size as compared with goldmani suggests affinity with perda but the greater width of the light-colored underparts, which averages 24 (extremes 18-32) per cent of the greatest width of the color of the upper parts, shows approach to goldmani. Farther north, in Chiapas, however, specimens of perda from San CristÓbal and San Vicente are readily distinguishable from those of goldmani taken a few miles away at Pinabete and near Teopisca. The latter two localities are, however, several thousand feet higher than San CristÓbal (Chiapas) and San Vicente. Two of the nine skulls (only 3 adult) examined for malformation of the frontal sinuses reveal infestation by parasites.
Mustela frenata nicaraguae AllenLong-tailed Weasel Plates 1, 25, 26, 27 and 30
Comparison of the skull of the male with that of M. f. costaricensis is made in the account of that subspecies. As compared with that of M. f. perda, which it most closely resembles, the skull of the male has a narrower, shorter rostrum, lesser interorbital breadth, lesser mastoid and zygomatic breadths and slightly shallower braincase, measured at anterior margin of basioccipital. The tympanic bullae are slightly less projected, at their anterior margins, from the braincase and the squamosal, directly anterior to each, is a little more convex ventrally. The skull of M. f. nicaraguae is, then, slightly shorter than that of M. f. perda and relatively narrower. Remarks.—When naming this form, Allen (1916:100) characterized it as "Similar to M. tropicalis tropicalis but general coloration much darker and the white face markings somewhat reduced in area." In the sentence preceding the one quoted, Putorius tropicalis perdus was placed as a synonym of Putorius tropicalis tropicalis. M. f. nicaraguae and M. f. perda are nearly alike in color and color pattern but differ in cranial characters. M. f. perda and M. f. tropicalis are widely different in color and more especially in color pattern but differ only slightly in cranial characters. The aggregate difference between perda and nicaraguae is less than that between perda and tropicalis. All three are lowland forms and each is smaller than the adjacent highland forms, namely, M. f. goldmani, macrophonius, perotae and frenata. The weasels from Honduras definitely are not typical of nicaraguae as it is known from the specimens from Nicaragua itself. The specimens from the state of Tegucigalpa, Honduras, are larger. Some are darker than topotypical nicaraguae. The dorsal outline of the skull is more nearly flat (less convex) in some. In these and several other differential features studied, the average of specimens from Tegucigalpa is intermediate toward goldmani, but everything considered the animals seem best placed with nicaraguae rather than with goldmani or perda, to which latter also, they show some resemblance. With better material from Nicaragua and additional specimens from Salvador (here referred to goldmani) a restudy of all the material now referred to the three races named would be profitable. Aims of this restudy might be to determine if a highland race additional to goldmani should be recognized and if the lowland races perda and nicaraguae differ from one another in the way that the existing specimens indicate. In the five males from Matagalpa, the narrow white band in front of each ear is confluent with the color of the underparts on one side only in one specimen and on both sides in two specimens. None of these bands is confluent with the white patch between the eyes. A dark spot at the angle of the mouth is present on one side in one specimen. The corresponding area is dark colored in all other specimens but not separated from the color of the upper parts. In the specimen from San Rafel del Norte the white bands are not confluent with the color of the underparts. The female from Mambacho has the mentioned bands confluent with the color of the underparts. This female approaches M. f. costaricensis in the dark color of the upper parts but has more extensive white facial markings than some specimens from much farther north. Like a female seen of M. f. costaricensis, this one has a "frosted" nape but the white hairs on the back of the neck are less numerous than in the female of M. f. costaricensis. M. f. nicaraguae in typical form, then, is thought of as a small, lowland, tropical subspecies only slightly differentiated from M. f. perda. By reason of its intermediate characters, it constitutes a link between the lowland forms, and the larger animals called M. f. goldmani and M. f. costaricensis. None of the four skulls from Nicaragua shows signs of infestation of the frontal sinuses by parasites.
Mustela frenata costaricensis GoldmanLong-tailed Weasel Plates 25, 26, 27, 28, 29 and 30
Comparison of the skull of the male with that of M. f. panamensis has been made in the account of that subspecies. As compared with that of M. f. nicaraguae the skull of M. f. costaricensis is heavier and in every measurement taken is larger. The skull is generally more massive and it follows that most measurements of depth and width are greater in relation to the basilar length as well as actually greater. The individual teeth are larger and the tympanic bullae wider and at their anterior ends are more projected from the braincase. Indeed the skull is more like that of M. f. goldmani than like that of M. f. nicaraguae. Remarks.—The half dozen ill-prepared skins, with partial skulls inside, of this form in the United States National Museum long were referred either to Mustela brasiliensis or Mustela affinis. It was not until 1912 when Goldman studied these specimens that the distinctive characters of the Costa Rican weasel were recognized and made the basis of the name costaricensis. M. f. costaricensis is well differentiated from M. f. nicaraguae and M. f. goldmani which occur to the northward and from M. f. panamensis which occurs to the southward and is a large, heavy-skulled, dark-colored animal with white facial markings restricted or absent. In the type specimen and the female from the Candelaria Mountains the white facial markings are only narrow facial bars or a few white hairs, but in the young male from Cervantes there is a well developed bar 6 millimeters wide on each side of the face and a separate nasofrontal spot, 10 x 12 mm. The young female from CachÍ has a V-shaped frontonasal spot, on the right side of the face a white bar 5 mm. wide and 17 mm. long connected with the color of the underparts, and on the left side a white spot in front of the ear and another between the ear and eye. White facial markings were not recorded in the other specimens. The color of the upper parts is only a little less dark than those of M. f. panamensis. Owing to the numerous white hairs on the dorsal side of the neck, the nape of the female from the Candelaria Mountains has a frosted appearance not present in other specimens. M. f. costaricensis is a large animal and among its geographic neighbors is approached in size only by a specimen of panamensis from Boquete, PanamÁ. Also the young male from Cervantes suggests panamensis in the less flattened interorbital region, but even so is more like costaricensis. The small size of two young males, one from Navarro and the other from the vicinity of San JosÉ, is suggestive of M. f. nicaraguae. However, the large size of most of the specimens and the configuration of the skull are more as in M. f. goldmani than in M. f. nicaraguae and thus suggest that the known specimens are of high mountain subspecies. The long black tip of the tail is another point of resemblance to M. f. goldmani, the high mountain subspecies to the north. Perhaps in the lowlands of Costa Rica, there are weasels of another subspecies. Of the eight skulls examined for malformation of the frontal sinuses, each of the two adults and two subadults shows signs of having the frontal sinuses infested with parasites.
Mustela frenata panamensis HallLong-tailed Weasel Plates 1, 25, 26, 27, 28, 29 and 30
The skull of the one adult female from ChiriquÍ is 58 per cent lighter than the average of the two adult males. The skull of the male of M. f. panamensis as compared with that of M. f. meridana, is heavier and averages larger in nearly every measurement taken. Relative to basilar length, tooth-rows, orbitonasal length, interorbital breadth and zygomatic breadth averaging narrower. Mastoid breadth always narrower. Tympanic bullae longer, narrower, and usually slightly less protruded. P4 and m1 larger. Dorsal outline of skull, viewed laterally, more convex. Postorbital breadth actually and relatively greater. Postorbital processes, mastoid processes, and sagittal crest not so well developed. Differences between skulls of females, in so far as known, similar to those described between males. As compared with M. f. costaricensis, M. f. panamensis has a lighter skull averaging smaller in every measurement taken except interorbital breadth, which is greater. Relative to basilar length, width of rostrum, interorbital breadth and depth of skull at plane of upper molars, less. Tympanic bullae shorter, narrower, less protruded. P4, M1, and m1 larger. Dorsal outline of skull, viewed laterally, more convex. Postorbital breadth relatively and actually greater. Postorbital processes, mastoid processes, sagittal crest and lambdoidal crest less developed. No skull of an adult female of M. f. costaricensis is available for comparison. Remarks.—This subspecies had not been recognized by previous workers because specimens from PanamÁ were supposed to be Mustela affinis Gray up until 1916, when Allen (1916:100) restricted the type locality of M. affinis to BogotÁ, Colombia. At that time Allen referred specimens from PanamÁ to Mustela affinis costaricensis, and Goldman (1920:161) followed Allen. The specimens examined show much variation. Part of this is geographic variation. For instance the specimens from Boquete approach M. f. costaricensis in size more than do those from farther south. Too few adult females have been seen to ascertain the amount of secondary sexual variation. Bangs (1902:49) suggested that the sex of no. 10113 was wrongly recorded and that it was not really a male. If so, this would reduce the range of apparent variation in size of males from Boquete by half and bring it into accord with the amount normally existing in adult males from one locality. No. 10113 is adult but the skin shows no mammae which would prove it to be a female instead of a pigmy male. Although even smaller than 10113, the type specimen is so much larger than females of M. f. meridana that I have wondered if it is correctly sexed. However, the fact that it was sexed by E. A. Goldman, a collector of wide experience, lessens the possibility that a mistake was made. The color of the underparts is more restricted in panamensis than in any other subspecies of the species. Excluding the specimen from Mt. Pirre, the least width of color of the underparts averages 16 (extremes 6-24) per cent of greatest width of the color of the upper parts. This feature, together with the black color, imparts an appearance to the PanamÁ weasel that is strikingly like that of a mink. M. f. panamensis is one of the two blackest weasels; M. f. aureoventris is the other. Each of these subspecies occurs in a region of heavy rainfall and there clearly is a positive correlation between high humidity and intensity of color. The black tip of the tail, as regards extent, here reaches the maximum attained among Central and South American weasels. The foot soles are less hairy than in any other member of the subgenus Mustela. The tympanic bullae are lower and less inflated than in any other subspecies of the species. Adequate specimens from central and southern PanamÁ may reveal the existence of one or more additional subspecies since animals from each of the three localities now represented differ from those from the other two and some of these differences are correlated with geographic position. However, specimens from all three localities agree in several features. For example all of them have the dorsal outline of the skull highly convex, transversely, and, more especially, longitudinally. In this respect they are sharply differentiated from any other American weasel. Nevertheless, M. f. panamensis is clearly a link between the North and South American subspecies and panamensis intergrades with the adjacent subspecies. The large size of the skull and teeth and the slightly more ventrally projected tympanic bullae of no. 10112 from Boquete approach features seen in M. f. costaricensis. The smaller size of skull and teeth of no. 178970 from Mt. Pirre are points of resemblance to M. f. meridana. The type specimen was selected from a region where M. f. panamensis is thought to have its distinctive characters well developed. The specimen is not adult and, therefore, does not show as many differential characters as does a nontypical adult from Boquete. Nevertheless, the majority of the above mentioned differential characters are shown by the type specimen and an adult from the same place would, it is judged, show all the differential characters better than would an adult from Boquete. Of the 11 skulls examined, 6 show no signs of having had the frontal sinuses infested with parasites.
Mustela frenata meridana HollisterLong-tailed Weasel Plates 25, 26, 27, 37, 38 and 39
Comparisons of the skull with those of M. f. panamensis and affinis have been made in the accounts of those subspecies. As compared with the skull of the male of M. f. aureoventris, that of meridana averages smaller in every measurement taken. Indeed, none of the skulls of meridana equals that of aureoventris in basilar length, length of tooth-rows, length of tympanic bulla, depth of skull at anterior margin of basioccipital or at posterior margin of upper molars, or measurements of teeth. Relative to the basilar length, most of the measurements are greater in meridana. Exceptions are the relative length of the tooth-rows, and the two measurements of depth of the skull which average less. Remarks.—In 1914 when Hollister named this weasel he compared it with M. f. affinis and most of the differential characters which he ascribed to meridana were merely "more than" or "less than" in affinis. In affinis, Hollister included specimens from ChiriquÍ, PanamÁ, and the coast of Venezuela. The specimens from these three places were referred by Allen (1916:101) to Mustela affinis costaricensis, and he restricted (op. cit.:100) the type locality of Mustela affinis affinis to BogotÁ, Colombia, and synonymized Mustela meridana with M. a. affinis. Hollister probably would not have named meridana had he had specimens from BogotÁ for comparison and had he regarded them as topotypes of affinis for the difference is slight. Nevertheless, within the large geographic range of M. f. meridana there is some geographic variation. There is more of such variation in the color of the pelage than in shape and size of the skull. The specimen from San JuliÁn is darker than the average and in this respect approaches true panamensis. San JuliÁn is situated at a relatively low elevation on the coast of Venezuela. M. f. meridana so closely resembles M. f. affinis that the writer has no quarrel with anyone who would synonymize meridana. However, as represented by topotypes, the two races unquestionably are, on the average, different, and specimens from the southeastern part of the range of affinis probably are individually distinguishable from topotypes of meridana. Variation in the skulls of the series from MÉrida is relatively small. This applies to both males and females. The external measurements recorded by native collectors are not accurate to within more than five millimeters but, considering this, variation in external measurements also seems to be slight. The difference in size of the two sexes appears to be uniformly greater than in weasels from Central America. The twenty-six topotypes show that the color and color pattern are relatively uniform. All are of nearly the same tone except juveniles or young which are, as in the case of panamensis, much brighter colored on the underparts. Also, the young have darker-colored upper parts. The adults, without exception, have numerous white hairs scattered over the back of the head, neck and between the shoulders. I have no trustworthy evidence to support the suggestion that these white hairs are the results of tick bites or that they are caused by other parasites which damage the hair follicles. The white facial markings vary relatively little in the 45 specimens carefully examined in this regard. Also, the variation in color pattern of the two sides of the head is small. Indeed, within rather narrow limits, the color of the two sides of the head is the same in every specimen except two. In these two the white spots anterior to the ears are confluent with the color of the underparts. Only one specimen, no. 21342, has a white spot between the eyes and this spot is small. Ten of the twenty-six specimens have a definite white spot or band in front of each ear. Two specimens have such a spot on one side only. The dark spots at the angles of the mouth are present on two sides in three specimens and on one side only in three others. The mentioned spots are, then, present nine out of a possible fifty-two times. When the spots are absent, dark color usually is present in the required area but is confluent with the color of the upper parts. A young male from San JuliÁn, Robinson and Lyon (1901:147) state "... was shot ... as it ran over some bowlders in a ravine. Its eyes shone with the same greenish light as do the eyes of our common weasel, and it emitted the same strong odor." No. 14463, Am. Mus. Nat. Hist., from RÍo Zapata, Colombia, according to data on the label, was "taken in timber belt in valley in balk hills" and the native name is Cosonebi. Two specimens taken on the PÁramo de Tama, head of Tachira River, Venezuela and Colombia are commented on by Osgood (1912:61) as follows: "One ... was caught in a steel trap baited with birds and set by the side of a rushing mountain stream.... The other was shot in midday as it came prowling about our 'house' in the clearing...." Of the thirty-three skulls before me, twelve have the frontal sinuses malformed by parasites. These twelve include most of the adults for few of the subadults and fewer of the young show pathologic conditions in the frontal region. Note on localities.—Several of the localities in Colombia mentioned in "Specimens examined" are described and located by Chapman (1917:640-656, pl. 41) in his "Distribution of Bird-life in Colombia." Place names for Colombia on labels, not found on any map, or duplicated names of which I can not certainly select one, are RÍo Barrotow, RÍo Oscuro, RÍo Zapata, RÍo Japata, Guasca and El Baldro. Sonson may or may not be the town of that name situated some eighty miles northwest of BogotÁ and on the east flank of the Central Andes west of the Magdalena River on the drainage of the Cauca River. In Venezuela most of the specimens from MÉrida are labeled 1630 meters, Montes de MÉrida. San JuliÁn is some seven miles east of La Guaira (see Robinson and Lyon, 1901:136). San Esteban is located a little way back from the coast between Puerto Cabello and Valencia. PÁramo de Tama is on the Venezuelan-Colombian border near the source of the Tachira River (see Osgood, 1912:35). Mt. Duida is shown as at 3° 30´ N and 65° 40´ W by Chapman (1931:13) and Mt. AuyÁn-tepui as near 5° 15´ N and 62° 50´ W by Chapman (1937:760).
Mustela frenata affinis GrayLong-tailed Weasel Plate 30
As compared with M. f. meridana the skull of the male is larger, to the average amount of 2.2 mm. in basilar length and 1.2 mm. in zygomatic breadth of adults; length of tooth-rows and mastoid breadth average greater but relatively less; breadth of rostrum, interorbital breadth and orbitonasal length average actually and relatively less. Thus the skull of affinis is longer and broader, but the facial region is actually, as well as relatively, smaller. As compared with the skull of the male of M. f. aureoventris, that of M. f. affinis is about the same in basilar length. However, in no specimen of affinis are the measurements of length of tooth-rows or breadth of rostrum, actually, or relatively, as great as in aureoventris. The same is true of all measurements taken of M1, P4 and m1. The specimens from the vicinity of Quito and north of there, although referred to macrura, are nearly as dark as typical affinis, approach affinis in cranial characters, and indicate intergradation of affinis with macrura. Remarks.—Mustela affinis was named by John Edward Gray in 1874 (p. 375) on the basis of a specimen from New Granada. Although usually synonymized with Mustela brasiliensis by later authors until 1896 when Merriam (1896:31) applied the name to weasels from Costa Rica, nearly all the South American and several of the Central American weasels have, at one time or another, had Gray's name, affinis, applied to them. Gray, in 1865 (p. 115) when giving measurements of Mustela aureoventris, probably mentioned the specimen, that later became the holotype. In 1916 (p. 98) Allen restricted the type locality to BogotÁ, Colombia. Allen's action was a necessary procedure in clearing up the systematics of South American weasels and was based on good grounds. As set forth by Allen (loc. cit.), and more in detail by Chapman (1917:642), BogotÁ has long been the shipping point for Colombian vertebrate specimens, many of which were obtained in the mountains to the east. Allen (1916A:220) quotes Thomas as saying that the type specimen was purchased from Stevens at about the same time that a number of Colombian birds were purchased from the same dealer. Also, specimens from BogotÁ agree with Gray's description of the type specimen. Mustela frenata affinis, as here defined, constitutes one of the several slight geographic variants met with, on the sides of, and between, the three north and south mountain chains of Colombia. The others are lumped under the name Mustela frenata meridana. M. f. affinis, in common with specimens from the northern part of the range of macrura has large teeth. Weasels of all of the region from Quito to BogotÁ have large teeth. To the north there is the smaller-toothed meridana and to the south the smaller-toothed macrura grading into the still smaller-toothed agilis, and boliviensis. Two skins, without corresponding skulls, from Caqueta are lighter colored than any others of affinis; possibly the skins are faded by exposure to light. Since they probably come from an elevation of less than 1000 feet in the Amazonian region, they may pertain to another subspecies. Complete, unbroken, skulls of affinis are needed to ascertain the degree to which affinis and meridana differ in cranial features. The several specimens from the immediate region of BogotÁ show well the color and the color pattern but lack collectors' measurements. None of the ten skulls examined shows malformation of the frontal region due to infestation of the frontal sinuses by parasites. Possibly three of the four adults were infested, although not severely.
Mustela frenata aureoventris GrayLong-tailed Weasel
Remarks.—This subspecies of the Tropical Life-zone, or at least the Subtropical Life-zone, of Ecuador, in certain cranial characters resembles Mustela frenata macrura of the Temperate Life-zone. The two differ markedly in color. Nevertheless, a large number of the specimens collected in Ecuador are intermediate in color as well as in zonal distribution. The type specimen is young or a juvenile. The measurements of no. 34677 from Gualea indicate an animal similar in size to M. f. affinis. Gray (1864:55) states that the type specimen measures "Length of body and head 6 inches, of tail 4-1/2 inches." The plate (pl. 8) accompanying Gray's original description (loc. cit.) is marked one-half natural size and represents the animal as having a head and body length of eight and one-half inches. One year later Gray (1865:115) gives the measurements of this species as "Length of body and head 12, tail 8 inches." Since he had at this time another specimen, larger than the type specimen (which specimen later, probably, became the type of Mustela affinis Gray), the larger measurements probably were taken from it. Geographically, and as regards cranial characters, Mustela frenata aureoventris is most closely related to M. f. affinis and to the northern section of M. f. macrura, but in color to M. f. panamensis. M. f. aureoventris and M. f. panamensis are the two darkest-colored subspecies and each occurs in a region of extremely heavy rainfall. There is a skin only, no. 32620, Amer. Mus. Nat. Hist., from Munchique, obtained on June 1, 1911, which is appreciably darker than specimens of M. f. affinis in corresponding pelage and is intermediate between M. f. affinis and M. f. aureoventris in color as it is geographically. The specimen measures 495, 202, 52. The name Mustela aureoventris Gray has been regarded by most authors as preoccupied by Mustela auriventer Hodgson (1841:909). However, the writer is not of this opinion and agrees with Thomas (1920:224) that "The name aureoventris is not invalidated by the auriventer of Hodgson, as, apart from 'one-letterist' differences, its first half comes from the adjective aureus, while Hodgson's name is based on the substantive aurum, so that not only the spellings but the derivations are different." The spelling of Gray's name should be aureoventris for this is the spelling in the original description which in pagination precedes the colored plate of the animal that is labeled Mustela aureoventris. Putorius brasiliensis var. aequatorialis Coues (1877:142) is the only name known to the writer that has been proposed as a substitute for Mustela aureoventris Gray. Thomas (1920:224) treats Mustela macrura Taczanowski as a synonym of Mustela aureoventris Gray. Allen (1916:101) also treats the two names as applying to the same kind of weasel but regards aureoventris as preoccupied and therefore uses the name macrura. Taczanowski's original description (1874:311) and plate of Mustela macrura indicate an animal that is lighter colored than M. f. affinis. Gray's original description (1864:55) and plate of aureoventris indicate an animal that is darker colored than M. f. affinis. Indeed Gray (1865:115) in speaking of the type of aureoventris as compared with an adult from New Granada [= Colombia] that probably later became the type specimen of Mustela affinis, states: "The young from Quito is much darker than the adult;...." Comparison of the plates accompanying the original descriptions of aureoventris and macrura well illustrate the difference stated in the written descriptions. My examination of the type specimens of M. macrura and M. f. aureoventris shows them to have been fairly accurately portrayed in the plates accompanying the original descriptions. Accordingly the two names are used for the two kinds of animals which appear, however, to be only subspecifically distinct. Comparison of Gray's plate (1864, pl. 8) with the available specimens from South America indicates that the name aureoventris is based on an individual that is lighter colored than no. 34677 Amer. Mus. Nat. Hist., from Gualea, Ecuador, but on one which resembles no. 34677 more than it does the lighter-colored specimens from the Temperate Zone of Ecuador and northern PerÚ. Because Quito, Ecuador, is in the Temperate Life-zone and because the available specimens from this zone in Ecuador and northern PerÚ are distinctly lighter colored than Gray's plate representing the type of aureoventris shows this specimen to be, it is judged to have come from an altitude lower than that of Quito (9350 feet, according to Chapman, 1926:717); probably it came from the Subtropical Life-zone of Ecuador. Indeed Gray (1864:55) did not say that the specimen was collected or obtained at Quito but that it was "... received from Quito...." Chapman (1926:717) has pointed out that Quito, since 1846 has been the distributing point for bird skins which specimens "... come from the vicinity of the city, from the 'Napo' region on the Amazonian slopes of the Andes, and from Nanegal, Gualea, and other localities on the Pacific side rarely below the Subtropical Zone." It is also pointed out that only some of the specimens are labeled with their approximate place of capture and that even then these localities cannot be accepted as definite; they indicate mainly whether the specimen is from the eastern or western side of the Andes. The above mentioned considerations and information gained by study of the specimens cause me to think that the type is an intergrade tending toward the lighter-colored Mustela f. macrura of the Temperate Zone although sufficiently dark to be referred to the dark subspecies represented by no. 34677 Amer. Mus. Nat. Hist., from Gualea, Ecuador. The skull of no. 34677 shows no infestation of the frontal sinuses by parasites.
Mustela frenata helleri HallLong-tailed Weasel Plates 27, 28 and 29
The skull of the male is generally large and heavy as are the teeth. Comparison with macrura is made in the account of that subspecies. From males of affinis those of helleri differ in: skull shorter; breadth of rostrum and interorbital breadth actually and relatively greater. Remarks.—The five specimens examined of this subspecies were taken by Edmund Heller for the Field Museum of Natural History in 1922 and 1923. It is to honor his contributions to mammalogy that the subspecies is named helleri. No. 24135 is the specimen carried as a pet for some time by Mr. and Mrs. Heller and of which Mrs. Heller (1924:481) has given an account. This subspecies is insufficiently known, especially as to geographic range; probably it occupies a considerable range in the Tropical Life-zone along the eastern base of the Andes. The three females, two from Ambo and one from Huanuco, come from a much higher altitude than do the two males and the climate is said to be arid at Ambo and Huanuco. The skulls of the females are 62 per cent lighter and correspondingly smaller in measurements, than those of males. This difference is more than that found in any other South American weasel and it may be that the females are of a subspecies other than helleri. The type specimen has a broad skull with major proportions strikingly like those of Mustela stolzmanni. Possibly the similar climatic conditions under which the two live have left their impress in similar fashion in this part of each of the two species. The teeth, tympanic bullae, and certain other parts of the skull are, however, so differently proportioned as to show that the skulls represent two species. The referred male has a much longer skull than the type specimen and the relative proportions of breadth and depth of the two skulls differ widely. Judging from large series of weasels examined from localities outside the range of M. f. helleri, the two skulls probably represent almost the maximum of individual variation occurring in one subspecies. The dark color is as might be expected since helleri inhabits the humid Tropical Zone. None of the five skulls shows signs of having had the frontal sinuses infested by parasites.
Mustela frenata agilis TschudiLong-tailed Weasel
To judge from the skull of the female from Macate and the skull of the male from Lima, the skull and teeth of agilis are smaller than in any other South American subspecies of Mustela frenata, except M. f. boliviensis. Remarks.—Tschudi almost certainly used the name Mustela agilis in a composite sense. His statement (see quoted matter below) about the marked variation in color of this species, as represented by the skins carried by the Indian women as purses, indicates that the forms here designated as Mustela macrura, M. helleri and possibly others additional to the one here called agilis were included by him under the name Mustela agilis. Taczanowski took account of Mustela agilis when he described other species from PerÚ. Allen (1916:104) and Thomas (1920:224) were not convinced that Mustela agilis and Mustela macrura were distinct species or subspecies. Search on August 28, 1937, in the MusÉe d'Histoire Naturelle, at Neuchatel, Switzerland, by Mr. ThÉodore Delachaux, assistant there, and the writer, revealed no trace of weasels from Tschudi's collection, although some other specimens of mammals that he figured in the "Fauna Peruana" are preserved in that Museum. Not only were the collections of specimens examined but the new catalogue and old catalogue of mammals were vainly searched for mention of weasels deposited by Tschudi. Later, at the British Museum of Natural History, on p, 105 of a personal notebook, of the late Mr. Oldfield Thomas, record was found of his fruitless search for the same specimens of Mustela in May, 1902, at Neuchatel. Although Tschudi certainly used the name Mustela agilis in a composite sense, as subspecies are at present understood, his description most nearly applies to the light-colored animals from western PerÚ—the lightest colored of any South American weasels seen. They are of approximately the same color as North American subspecies inhabiting semiarid regions, for example Mustela frenata longicauda of the Great Plains. Another, but in my opinion less weighty, justification for applying Tschudi's name agilis to these light-colored weasels of western PerÚ is that by one line of reasoning, Taczanowski in naming macrura (jelskii is a synonym of it) from farther eastward in PerÚ, and that Hall in naming helleri from still farther eastward, and boliviensis to the southeastward, geographically restricted the application of the name agilis. Hall's action did this because he recognized geographic variation and employed the subspecies concept. Taczanowski, however, proposed his name macrura for a kind of animal which he indicated was specifically (as opposed to subspecifically) distinct from agilis and his account (1881:649) of jelskii indicates that he thought Mustela agilis Tschudi might occur in the same place as the animals which he named as new kinds. Thus, we can not credit Taczanowski with intent to restrict the name agilis geographically, even though later authors may choose to rule that his naming of macrura in effect did so restrict the application of Mustela agilis Tschudi. The equivalents in millimeters given by Allen (1916:104) for Tschudi's measurements of 9 to 10 inches entire length, and tails of 4 inches to 4 inches and 4 lines, apparently are based on the London scale in use today. If Tschudi employed the Rhine scale also of eight lines to the inch, but one which has the foot longer by an amount of 20 millimeters, or the Leipzig scale in which the foot is 22 millimeters shorter than the London foot, the measurements recorded by Tschudi differ in one direction or the other from those computed by Allen. However, knowledge of which scale Tschudi employed would not help much, if any, in more precise application of the name agilis because he does not indicate whether his measurements are of male or female animals; animals of the two sexes of the same subspecies differ more in external measurements than animals of the same sex of different subspecies of Peruvian weasels. Specimen no. 565, in the Polish Museum of Natural History, without definite locality, is provisionally referred to this subspecies. The specimen is intermediate in several respects between the female from Macate and the one of macrura from Cutervo.
None of the three skulls referred to this subspecies shows infestation of the frontal sinuses by parasites.
Mustela frenata macrura TaczanowskiLong-tailed Weasel Plates 1, 27, 28, 29, 30, 37, 38, 39 and 40
As compared with that of helleri, the skull of the male of macrura from JunÍn southward has a lesser mastoid breadth, notably smaller teeth, and a flatter skull which averages lighter throughout. The skulls of females available indicate that the skull and teeth are larger than in agilis. Remarks.—Seven years after Taczanowski named this subspecies, he applied the name jelskii to a female taken farther north than the original examples of macrura. As indicated in synonymy, various other names have been applied to animals included by the present author in this subspecies. Mustela frenata macrura intergrades with M. f. affinis as shown by practically all the referred specimens from north of JunÍn. As one proceeds northward the color of the weasels becomes progressively darker and the teeth become larger until the conditions found in affinis are met with near the northern border of Ecuador. From the material available it appears that the light-colored upper parts found in macrura characterize weasels of, at least, the Temperate Zone, from Marcapata, PerÚ, to near Quito, Ecuador. West of the range of macrura there exists the still lighter-colored subspecies, M. f. agilis. Immediately adjacent on the north, east, and south, darker-colored weasels occur. So far as color is concerned, the geographic range of the subspecies M. f. macrura is not difficult to define. However, the small size of the teeth characterizes only that part of this light-colored subspecies from JunÍn southward including the subspecies boliviensis at the southern extremity of the range of the species. From Cutervo northward the light-colored weasels of the Temperate Zone have teeth similar in size to those of the darker, more northern affinis. To designate the slightly larger-toothed, light-colored animals from Ecuador as a subspecies distinct from affinis and macrura is one solution but at present it seems best to refer all of these light-colored animals to macrura. The type specimen and topotype no. 562 differ more in the amount of inflation of the tympanic bullae than adult males of comparable ages from a given locality usually do. In other respects, the differences between the two skulls are not greater than those ordinarily found in specimens from the same locality. No. 562 has the tympanic bullae greatly, relative to the other South American weasels, inflated posteriorly. Otherwise, the bullae agree with those of the type specimen. Specimens from southwestern Ecuador, average large, and include the largest specimens of the species Mustela frenata seen from South America. A subadult male, no. 61406, in the American Museum of Natural History, is the largest. Its external measurements are 482, 191, 56. The basilar length of the skull is 48.2 and the zygomatic breadth is 30.3. Although not so large as this specimen, the corresponding measurements of specimens from Alamor, El Chiral, and even from as far away as Sigsig also are distinctly large. The skull of the female from Ollantaytambo and that of the male from Marcapata have teeth equally as small as do the specimens from Lake JunÍn. The skin alone, no. 194328, from Ollantaytambo has the color of the underparts extended over the entire upper sides of the forefeet. The male from Marcapata has less of this color on the forefeet and is in this respect intermediate between the specimens from Lake JunÍn and the one from Ollantaytambo. In size of teeth the female, type specimen of M. jelskii, from Cutervo, shows an approach to the larger-toothed weasels of the northern part of the range of macrura. The specimens in the Riksmuseum from the vicinity of Quito, Ecuador, have been rather fully described by LÖnnberg (1921:11-17) and need little comment here, except to say that they show, as he suggested, that the weasel of the Temperate Zone of Ecuador is an intermediate link between M. f. macrura and M. f. affinis. The adult female and juvenal male labeled as from Ambato have little left of the skulls except some of the teeth and the assignment of the specimens to the subspecies macrura is made mainly on geographic grounds. These two specimens probably are part of the shipment of birds and mammals of which Chapman (1926:703) speaks as follows: "A small collection of native-made skins purchased by the American Museum from a commission merchant in New York City as from 'Ambato' proved to be from the eastern slope of the Andes." Another skin in the same Museum, labeled by a native collector as from "Baeza arriba" [= above Baeza] is so dark colored and has the color of the underparts so much restricted, as to suggest that it belongs to the race aureoventris. Possibly, therefore, it was taken not at Baeza, Ecuador, which I find to the eastward of Quito at 77° 55' W and O° 25' S, but at some place of the same name on the Pacific Slope, unless the locality has been altogether wrongly recorded on the label. If the specimen was taken near the Baeza above referred to, then it gives evidence of an unnamed race of Mustela on the eastern slope of the Andes, characterized by its dark color. Unfortunately the specimen is young and its skull therefore offers insufficient basis for the judging of its subspecific relationships. Other specimens, in the British Museum of Natural History, recorded as taken "near Quito" and here tentatively listed under macrura, mostly, include specimens so dark colored as to lead me to think they came from country, lower than Quito, adjacent to the range of aureoventris. Nematodes taken from the right frontal sinus of no. 562 from JunÍn proved to belong to the superfamily Oxyuriodea according to Professor W. B. Herms and Mr. O. L. Williams, who have independently identified them. Because these worms had been dried fifty-five years in the mounted specimen and were later boiled in cleaning the skull, a more accurate determination was impossible and whether or not they pertain to the same species found in North American weasels cannot be said. Of 18 adult skulls examined for this type of infestation, 13 were found affected as judged by the evident malformation of the frontal region.
Mustela frenata boliviensis HallLong-tailed Weasel
Remarks.—Apparently the first specimens of this race to find their way into a zoÖlogical collection were the two young males taken on February 17, 1904, at LimbanÍ, by Geo. Ockenden [sic.]. M. f. boliviensis is smaller than any other South American weasel except possibly agilis. Better material of the two races probably will show even agilis to be larger. Early in my study of Mustela after examination of the one young specimen, from LimbanÍ, in the United States National Museum, an account of this race was drawn up, but the account was discarded for want of satisfactory material and the animal was referred to macrura. Then, in 1937, when the two other specimens were studied, the race was formally characterized as different from previously recognized kinds. The collector has noted on the labels of the two young from LimbanÍ that they were shot in the afternoon when running together beneath bushes. The frontal sinuses of the type are malformed as a result of infestation by parasites.
Mustela frenata (?) gracilis (Brown)
Comparison and remarks.—The type specimen was the only individual referred by Brown (1908) to this species. The remaining material of weasels from this deposit was referred by Brown to his Putorius cicognanii angustidens. Examination of the original materials convinces the writer, too, that the specimens, except no. 12431, are of the species erminea [= cicognanii of Brown]. No. 12431 itself may possibly be erminea but is far more probably of the species frenata. The uncertainty is due to the fact that an occasional skull alone of a subadult male erminea is extremely difficult certainly to distinguish from a skull alone of an adult female frenata. This is true among Recent specimens in the northern Mississippi Valley today; more exactly in Iowa and southern Minnesota the females of frenata, oftentimes intergrades between the subspecies Mustela frenata longicauda, M. f. noveboracensis and M. f. primulina, by only the skulls are next to indistinguishable from certain, unusually slender skulls of male erminea. At other places where the ranges of the two species meet, this difficulty is not so often encountered. Also, the type of gracilis has the skull broken in such a way that the postglenoid length in relation to the length of the skull as a whole could not be accurately determined in this particular skull. The type specimen of gracilis surely is an adult and because of its small size is thought to be a female. Of known long-tailed weasels of the species frenata, gracilis is structurally nearest to M. f. primulina which occurs in the same region today and to M. f. noveboracensis, the long-tailed weasel of the eastern United States. M. gracilis differs from noveboracensis and agrees with primulina in possessing well-marked temporal ridges which fuse to form a low sagittal crest, in having the mastoid processes projecting farther, laterally, beyond the braincase, in having the anterior ends of the tympanic bullae produced below the squamosal rather than on the same plane with the squamosal, and in having the bullae more inflated anteromedially. M. gracilis differs from both noveboracensis (97 ? and 56 ? with skulls of comparable age) and primulina (64 ? and 24 ? with skulls of comparable age) in that the zygomatic breadth amounts to less than 58 per cent of the basilar length. Another difference from any one of the skulls of females of primulina is the longer rostrum, which, when measured from the posterior base of the postorbital process of the frontal to the anterior end of the nasal on the same side, amounts to more than 35 per cent of the basilar length. As pointed out by Brown (1908:182) this specimen represents the extreme of slender skull among known kinds of American weasels.
MUSTELA AFRICANA DesmarestTropical Weasel (Synonymy under subspecies) Characters for ready recognition.—Differs from Mustela frenata, the only geographically adjacent species of the genus, by: presence of thenar pad on forefoot; presence of a longitudinal, median, abdominal stripe of same color as upper parts; upper lips being broadly edged, entirely round, with color of underparts; failure of longest facial vibrissae to reach posterior margin of ear; absence of p2; relative flatness (see pl. 29, fig. i and pl. 39, fig. h) of tympanic bullae. Characters of the species.—Size large (total length of adults approximately 500 mm.); foot-soles naked; thenar pad present on forefoot; length of claws, measured on concave sides, less than one and one-fourth times depth of claws measured at bases; longest facial vibrissae not reaching posterior margin of ear; tail relatively long haired; tail at all ages terminating in point as is characteristic of only juveniles and very young of Mustela frenata and M. erminea; tip of tail, and muzzle, only slightly darker than remainder of upper parts; upper lips broadly edged with color of underparts; pelage coarse, harsh and sparse; longitudinal, median, abdominal stripe of same color as upper parts present; skull broad and deep; braincase large, rounded, and much inflated anteriorly; palatal region wide; tympanic bullae less inflated than in any other American species of the subgenus; angle of lower jaw reduced; dental formula 3 1 2-3 1 -, -, ---, -; 3 1 2 2 teeth heavy; medial lobe of M1 but slightly larger than lateral lobe. See plates 28, 29, 30, 39 and cranial measurements. Geographic variation.—The reddish versus chocolate color of the upper parts constitutes the only variation of a geographic nature so far detected. Remarks.—One of the most noteworthy of the several unique characters of this large, tropical weasel is the longitudinal, median, abdominal band. The species exhibits the minimum degree of development of certain features that become progressively less apparent as one proceeds southward from Central America. The relative uniformity of the coloration of the upper parts (reduction in intensity of black color on the muzzle and tip of the tail) and the reduction of the tympanic bullae are two cases in point. Viewed dorsally the general outline of the skull is most nearly matched by that of the skull of Mustela frenata meridana from Venezuela or that of M. f. helleri from PerÚ. However, the resemblance is not close. The tympanic bullae, although unique among American weasels, are more like those of M. f. meridana from Venezuela than like those of any other kind. The great postorbital width (relatively less in M. africana than in several South American subspecies of Mustela frenata) and small angular process of the mandible are characters, in varying degrees, also common to all South American weasels. Structurally M. africana clearly is more nearly like other subspecies of M. frenata from South America than it is like any species or subspecies from North America. Mustela africana is the most primitive of the American weasels. The distinctive cranial and dental characters, excepting the reduction in number of premolars, are of a primitive nature. For example, the relatively wide postorbital region, the large braincase that is inflated anteriorly, and the flattened, tympanic bullae, are points of resemblance to the holarctic Mustela erminea, which species is regarded as nearest the original stem form; also the mentioned characters correspond to ontogenetic stages passed through by other weasels. Mostly on these accounts, one is led to look upon M. africana as a migrant from North America. It may have become isolated from its original stock, by a water barrier in the Central American region, for a length of time sufficient to permit of a degree of differentiation to develop between it and the North American weasels which prevented crossbreeding with the frenata stock when that stock, at a later time, reached South America. This assumption is suggested only by evidence from the Recent specimens. No remains of true weasels (subgenus Mustela) have been recorded from deposits in South America older than the Recent period. The alternate possibility, that M. africana intergrades with some race of M. frenata in western or northern South America, has been considered and regarded as highly improbable. Cabrera (1940:15) has made the distinctive structural characters of Mustela africana basis of the generic name Grammogale to include the one species africana. I am inclined to accord Grammogale only subgeneric rank. It is possibly significant that Mustela africana is intermediate in several respects between Lyncodon and typical Mustela. The median, longitudinal, abdominal band of the same color as the upper parts in M. africana and the relative uniformity of the coloration of its upper parts might be considered as an intermediate stage between the dark, bicolored (black muzzle and tail tip and brown body) upper parts and light-colored underparts of the North American weasels on the one hand and the light, unicolored upper parts and dark-colored underparts of the Patagonian weasel (Lyncodon) on the other hand. The number of premolars, is also intermediate between the numbers 3 2 - and - 3 2 of the North American Mustela and the Patagonian Lyncodon, respectively. The American Mustela and the Patagonian Lyncodon, respectively. The more medially, as opposed to anteriorly, directed medial cusp of P4 (characteristic of approximately half of the specimens examined), and the structure of the skull in general of M. africana also seem to be morphologically intermediate between those parts of Mustela and Lyncodon. On the chance that Lyncodon is closely enough related to Mustela, to be included in a group with Mustela rather than in a group with Grisonella, it is worth noting that Lyncodon lujanensis Ameghino (1889:324, 325), from the villa of Lujan and at the city of CÓrdoba, at each place in the Pampean [= Pleistocene] formation of Argentine (see also Cabrera, 1928:263) is the first and only fossil form of this group recorded from the whole of South America. Actually, however, Lyncodon seems to me to be as nearly related to Grisonella, if not more so, than to Mustela. If Lyncodon is more closely related to Grisonella and Grison than to Mustela, then the above remarked intermediacy in characters of M. africana has more of interest as a tendency to parallelism than it has of phylogenetic import. Appraisal of phylogenetic relationships would require appraisal of the ancestral stem forms of the Grison stock and the Mustela stock. None of either is known from deposits of the Pliocene, the period of time immediately preceding the Pleistocene. None of the skulls of Mustela africana seen or figured has the nasomaxillary sutures entirely obliterated and the specimens would, judged on this character alone and by analogy with North American species, be regarded as young and subadult. However, the sutures close at what seems to be a later age than in M. frenata and M. erminea. The condition of the mammae in the type specimen of M. stolzmanni and in the specimen from Moyobamba, indicate that they have borne young. North American weasels old enough to bear young lack visible traces of the nasomaxillary sutures. I have examined no skulls of africana with greatly worn teeth and hence cannot say if the sutures are obliterated in advanced age. If available data be correct, this species is unique within the genus in that the two sexes are of approximately the same actual size and of the same relative proportions in the body and in the skull. There was no difference between individuals said to be of different sexes from ParÁ, described and figured by Goeldi (1904:61-62, pls. 1, 2). The undoubted female, type specimen of Mustela africana stolzmanni, is as large as the undoubted male, no. 37475, of the same species, but of a different subspecies, from ParÁ, Brazil. All the specimens of M. a. africana that I have handled are labeled male and those of M. a. stolzmanni female. More material may show that the female is smaller than the male, as is the case in all near relatives of M. africana. Little has been recorded concerning the habits of this species. Tate (1931:254) states that a live individual which he saw in a cage at ParÁ had been captured "swimming in the salt water of the estuary about half a mile away from the shore." On the label of the specimen from Moyobamba, there appears: "caught in Willow tree." Subspecies examined.—All described forms, of which there are two. Mustela africana africana DesmarestTropical Weasel
Remarks.—Desmarest in 1818 gave a remarkably good description of this animal which he named as a new species, Mustela africana, but mistakenly indicated that the single specimen known to him came originally from Africa. Until 1913 the name was applied, wrongly, to weasels of northern Africa or to those of the Azores Islands and St. Thomas Island. In that year Cabrera (1913:429) identified the species with the one later named Putorius (Mustela) brasiliensis paraensis by Goeldi (1897:556, pl. 21) from ParÁ, Brazil. Despite Cabrera's clear identification in 1913, and his later mention of the correct application of the name Mustela africana, it was not correctly employed by other authors, including myself who even as late as 1936 (p. 111) instead used Goeldi's name. In 1937 Mr. Cabrera called my attention to his published account of Mustela africana and so permitted me to examine the type specimen in the Paris Museum, whither I was bound when I received Mr. Cabrera's letter. My own examination of the specimen fully confirmed the conclusions published by Cabrera (1913:429). As a matter of historical interest, however, it is worth noting that Cabrera (1913) originally supposed the type specimen to have been taken as booty of war from Portugal by the French and that Cabrera later, at the request of P. Trouessart, pointed out (1914:176) that the specimen had been acquired in exchange ("a cambio") since according to Dr. Trouessart the Museum register showed that offer had been made to Portugal to return this and other specimens but that Portugal had replied that it had nothing to reclaim. Dr. P. Rode in August, 1937, at the Paris Museum, gave it to me as his opinion that the specimen had been an outright gift from the "Cabinet de Lisbonne" to E. Geoffroy St.-Hilaire on his trip to Portugal in 1808 when he was given also from the same cabinet several primates, all from Brazil. Of the labels attached to the pedestal on which the specimen is mounted, that of most ancient appearance is glued to the bottom of the stand and bears in a hand apparently written before Trouessart's entries on the same label, the information "Du Cabinet de Lisbonne 1808" and "J. H. S. 1809." The opened mouth of the mounted specimen permits one to determine that P2 is absent on each side above. The stuffed scrotal pouch and hair projecting downward about the preputial opening clearly show the animal to have been a male. The least faded portions of the mounted specimen, its sides, are of the same reddish color as characterizes adults from ParÁ and not of the darker chocolate color of specimens of M. stolzmanni from PerÚ. The specimen is indistinguishable from topotypes of P. paraensis of Goeldi and his name will have to fall as a synonym of Mustela africana Desmarest. Goeldi gave an extended description, with figures of the skull, head, and entire animal, when he named paraensis. As his account shows, he was unaware that Taczanowski had described a similar weasel from the headwaters of the Amazon, or for that matter that any weasel excepting Mustela affinis Gray, had been found in South America. Goeldi's later account of additional specimens (1904:61, pls. 1, 2) gives much useful information about the animal. Photographs of several specimens and photographs and detailed measurements of several skulls are presented by him. ParÁ, and CametÁ, Brazil, places from which Mustela africana africana is known, are nearly 2000 miles from the localities in eastern PerÚ and eastern Ecuador from which M. a. stolzmanni is known, and no specimens, from intermediate localities, are available to show actual intergradation of the two. However, the similarity in structure of the two weasels is so great as to indicate close affinity. Furthermore, it is understood that environmental conditions at and between the two localities are similar. These considerations, in the light of our knowledge of actual intergradation of geographic races of weasels in other places, cause me to treat, with a feeling of assurance, M. africana [= P. paraensis Goeldi] and M. stolzmanni Taczanowski as subspecies of a single species. M. Rodolpho Legueira RodrÍguez writes me, under date of June 16, 1928, that the type specimen of Putorius (Mustela) brasiliensis paraensis Goeldi is stuffed and preserved in a "vitrine" at the Museum Goeldi (Museum Paraense) De Historia Natural e Ethnographia, ParÁ, Brazil. The one young specimen seen, that from CametÁ, is darker colored than any of the four older specimens examined. It is almost exactly the Chestnut Brown of Ridgway (1912) and therefore approaches closely in color the adult specimens of M. a. stolzmanni. This same tendency to greater richness of color in young than in adults is seen also in Mustela frenata. Mustela africana stolzmanni TaczanowskiTropical Weasel
Remarks.—After the Polish naturalist, Stolzmann, in the course of his explorations in PerÚ, obtained the single specimen which was made the type, no other naturalist, so far as known, visited the type locality until thirty-two years later when Wilfred H. Osgood and M. P. Anderson spent more than a month collecting at Yurimaguas (see Osgood, 1914:147), but secured no topotypes of this little-known weasel. C. O. Schunke took the second specimen in the Valle del PerenÉ in April, 1921; L. Rutter on January 25, 1924, took the third specimen, and W. Clark-MacIntyre took the fourth specimen on the Jatun Yacu. This obscure place name is shown on the map (fig. 4, p. 827) published by Brown (1941) and is the stream flowing from the west to the town of Napo. Napo is situated at approximately 1° 2' S and 77° 49' W. In the female from Moyobamba there are only 3 pairs of mammae. One pair is inguinal and two pairs are on the posterior part of the abdomen. Taczanowski (1881:836) relates that this species was taken in the forest to which it appears to be restricted since the inhabitants of the village did not know of the animal. He points out also that the previously known Peruvian species [M. f. macrura and M. f. agilis] live in the treeless territory of eight to eleven thousand feet altitude whereas M. stolzmanni was found in the humid forest of the great plain of the Maynas at an elevation of 500 feet or less above sea level. The frontal sinuses of the specimens seen reveal no malformation as a result of infestation by parasites.
EXPLANATION OF CRANIAL MEASUREMENTS APPEARS ON PAGE 417 Fig. 31. Four views of the skull and a lateral view of the left lower jaw to show points between which measurements of the skull were taken. Based on M. f. primulina, from 3 mi. E Bergman, Boone County, Arkansas, obtained December 12, 1933, by B. G. Roberts; ad. ?. 62854 Mus. Vert. ZoÖl. × 1-2/5. |
|
