(1) Kangaroo rats may be separated with ease from all other mammals; the long tail and short and weak fore feet separate them from the pocket gophers; the white hip-stripe distinguishes them from the pocket mice. The decidedly larger size and the white-tipped tail separate Dipodomys spectabilis spectabilis and D. deserti from D. merriami and D. ordii. The darker color and vividly contrasted black-and-white tail of spectabilis distinguish it from deserti.

(2) Dipodomys s. spectabilis occurs in the open arid country of portions of the Lower and Upper Sonoran Zones of Arizona, New Mexico, Texas, Sonora, and Chihuahua. It lives in harder soil than does deserti, and builds more conspicuous mounds.

(3) There is no evidence of intergradation or hybridization between spectabilis and deserti.

(4) Dipodomys s. spectabilis is nocturnal; it is gentle, and does not offer to bite when taken in the hand; is silent for the most part; active; somewhat sociable with its fellows, but fights in defense of its food stores; progresses chiefly by leaping; signals by a drumming or tapping on the ground with its hind feet.

(5) The breeding season of spectabilis begins in January and continues into August. Whether more than one litter is raised in a single season is unknown. The number of young in each litter varies from 1 to 3, averaging 2.

(6) Dipodomys s. spectabilis does not hibernate, but provides food stores, mostly seeds, for use during seasons when food would be otherwise unavailable. Storage in each den varies in quantity from 5 grams (about 1/6 ounce) to 5,750 grams (12.67 pounds). Materials stored include several important forage plants; for example, various species of Bouteloua and Aristida, with B. rothrockii (crowfoot grama) the most important. Accessibility and abundance of different plants have much to do with the kinds of storage found.

(7) The dens of spectabilis are the most notable of all kangaroo rat dwelling places. They range from 6 inches to 4 feet in vertical height, and from 5 to 15 feet in diameter. Here the kangaroo rat has its home, shelter, and food-storage chambers. Within the den is found a tortuous network of burrows, with many storage and some nest chambers, the whole arranged so as to be two to four stories high.

(8) Dipodomys s. spectabilis is not of great economic significance, except locally, in ordinary seasons. During periods of extreme drought it may be of critical importance on grazing areas from the standpoint of the carrying capacity of the range.

(9) Kangaroo rats are easy to poison by following the same formula as that used by the Biological Survey for destroying prairie dogs.

(10) In many places unsuited to extensive grazing or agriculture spectabilis does no appreciable damage. It is one of the most interesting of all the rodents peculiar to our Southwestern deserts, and should not be molested except where it is destructive.