FRESH-WATER SNAKES.

THE frequent allusion to water snakes in the preceding chapters seems to render this a suitable place to describe them more in detail; and among them are of course the sea snakes, and ‘The Great Sea Serpent’ must not be omitted.

In many books on natural history, particularly if herpetology occupy any space, we find the subject wound up with a chapter on ‘The Sea Serpent,’ forming a sort of apologetic little addendum, as if the creature of questionable existence must claim no space in the heart of the volume, yet is not quite so unimportant as to be omitted altogether.

On the part of some other authors, a total and summary dismissal of the ‘monster’ is apt to exclude with it any reference to the smaller sea snakes, whose actual existence is therefore a fact less known than it should be; and many persons, seeing the doubt cast upon the celebrated individual whose reputed reappearance on the prorogation of Parliament has become an annual joke, conclude that all sea snakes are similarly mythical.

Admitting it to be a dubious creature, with neither name nor ancestry in ophidian annals, I must not give it precedence of the recognised water snakes; but it shall figure in the heart of my book notwithstanding.

‘Fresh-water snakes’ form the fourth, and ‘Sea snakes’ the fifth of the five groups into which Dr. GÜnther has separated the ophidian families; but the gradations between the land and the fresh-water species, and between the latter and the salt-water snakes or the true HydrophidÆ, are, like all other herpetological features, extremely close. There are water-loving land snakes and land-frequenting water snakes, that is, those which are equally at home in both. In the true water species, however, we find modifications of ordinary rules which show them to be peculiarly protected and adapted for an aquatic existence.

One notable characteristic in all, both salt-water and fresh, is the position of the nostrils on the top of the snout, and in many these are protected by a valve which closes at will. As air-breathing animals they must come to the surface, but the timid, stealthy ophidian instinct which seeks to hide from observation can be indulged even in the water, with the nostrils so situated that only a very small surface of the head need be exposed. Could we examine the interior of the mouth we should doubtless find some slight variation in the position of the glottis also. In a foregoing chapter we saw that the trachea opens exactly opposite to and close behind what Dumeril calls the ‘arriÈre-narines;’ ‘leur glotte qui est À deux lÈvres et qui represente un larynx trÈs simple, s’ouvre dans la bouche derriÈre le fourreau de la langue ... elle s’ÉlÈve pour se presenter dilatÉe sous les arriÈre-narines.’[71] The glottis of water snakes must have a still more upward direction to present itself to those air passages. Perhaps water snakes do not require to yawn so frequently as is the habit of their terrestrial relatives; and if they do, it must be a rare privilege to be able to inspect the process, as one can so frequently do with the pythons and vipers at home. Our authorities do not give us much information on this point.[72]

Their moderately long tapering tail is used as a propelling power. Exteriorly, too, water snakes have smooth non-imbricated scales, though exceptions exist in those species which frequent both land and water, as the Tropidonoti, a large family of which our common English ring snake is a member, and which, as their name denotes, have all keeled scales, from t??p??, t??p?d??, a keel. These, also, can elevate their ribs, and so flatten the body in the water, another assistant in swimming.

A marked exception to the smooth-scaled, water-loving snakes is the African viper, known as the ‘River Jack’ from its partiality to water. Vipera rhinosceros, from the spinous scales which have the appearance of horns on its nose, is allied to those described in the 18th chapter. Though not strictly a water snake, it much frequents it, and glides through it with ease, the more remarkable because, in common with those other ‘horned vipers’ of Africa, it has a short, insignificant little tail, which can be of little use as a propelling power. Altogether, it is one of the ugliest and most ferocious-looking of the whole serpent tribe, with a thick, heavy body, a dingy, rough exterior, and strongly-carinated scales. Excepting in colour, and a more horizontal inclination of its horns, it is not unlike the V. nasicornis of the coloured illustration, chap. xviii.

While all the HomalopsidÆ or true fresh-water snakes are innocent, there are many other venomous kinds known as ‘water serpents,’ both in Africa and America. For example, the ‘water viper,’ or ‘water moccasin,’ Cenchris piscivorus, whose aquatic and fish-eating propensities were described in the chapter on Tails. This ‘thorn-tail’ viper has not, however, the nostrils of the true fresh-water snakes or HomalopsidÆ. In Australia also are several poisonous species, known vernacularly as ‘water snakes;’ but strictly speaking, and on the authority of GÜnther, the true HomalopsidÆ are all non-venomous.

To describe these more minutely from GÜnther, Krefft, and Dr. E. Nicholson, ‘they have a body moderately cylindrical, a tail somewhat compressed at the root, and more or less prehensile. Many of them have a distinctly prehensile tail, by which they hold on to projecting objects;’ and in times of storms and strong currents we can imagine the importance of this security to them. Their eyes, though prominent, are small, and thus less exposed to injury; and the nostrils, as already stated, are on the upper surface of the head, and provided with a valvule. Another peculiarity is that the last or back tooth of the maxillary bone is a grooved fang, a transitional tooth between an ordinary one and a fang; but there is no evidence of any poisonous saliva connected with it. Indeed, as we may repeat, Dr. GÜnther distinctly affirms that all the fresh-water snakes are harmless and thoroughly aquatic, though a few are occasionally found on the beach. They inhabit rivers and estuaries, feeding on fish, and rarely coming to land; some of them frequent brackish waters, and even enter the sea. These latter in their organization approach the true marine serpents. One Indian example, Hydrinus, is semi-pelagic. They are all viviparous, producing their young in the water; and they belong to the tropical or semi-tropical regions. In Australia they are found only in the far north; but in America some so-called ‘water snakes,’ which spend most of their time in the water, frequent rivers which are frozen over in winter, during which season they probably undergo hibernation in holes near the banks.

Several of the older naturalists describe ‘water snakes’ in words which leave us no doubt as to the numbers, though of their name we cannot be so certain. Carver in 1796 mentioned some small islands near the western end of Lake Erie, so infested with snakes that it was dangerous to land upon them. It is impossible that any place can produce a greater number of all kinds of snakes, particularly the ‘water snake,’ than this. He says: ‘The lake is covered near the banks of the islands with the large pond lily, the leaves of which lie on the surface of the water so thick as to cover it entirely for many acres together, and on each of these lay wreaths of water snakes, amounting to myriads, basking in the sun.’ A sight of the last century this. I have passed over that part of Lake Erie and through the Detroit river, and remember the islands and the water-lilies and other attractive objects, but ‘wreaths of water snakes’ were not of these.

Lawson, too, can assure us of their habitat, but not their name, and his account is of worth chiefly to verify their swarming numbers. It is possible that some of those which he describes are now extinct or very rare. ‘Of water Snakes there are four sorts. The first is of the Horn Snake’s Colour, though less.’ (This might be the young of the ‘water moccasin,’ Cenchris, or Trigonoceph. piscivorus.) ‘The next is a very long Snake, differing in Colour, and will make nothing to swim over a River a League wide. They hang upon Birches and other Trees by the Water Side. I had the Fortune once to have one of them leap into my Boat as I was going up a narrow River. The Boat was full of Mats, which I was glad to take out and so get rid of him. They are reckoned poisonous. A third is much of an English Adder Colour, but always frequents the Salts, and lies under the drift Seaweed, where they are in Abundance, and are accounted mischievous when they bite. The last is of a sooty, black Colour, and frequents Ponds and Ditches. What his Qualities are, I cannot tell.’

Catesby is responsible for having called Tropidonotus fasciatus ‘the brown water viper,’ a stumbling-block to many ever since, much confusion existing between this and the true ‘water viper,’ the dangerous moccasin snake. Occasionally they are very dark. They are rather thick and viperish-looking as well, but are perfectly harmless.

This is the snake to which almost this book owes its origin, the specimens at the Zoological Gardens called ‘Moccasins’ tripping me up at the outset, as my preface sets forth. Holbrooke describes it as spending most of its time in the water, or about pond and river banks. It swims rapidly, and hundreds may be seen darting in all directions through the water. They are very common in the United States, and might have formed the ‘wreathed myriads’ on Lake Erie formerly. In summer they roost on the lower branches of trees, overhanging the water, like Trigonocephalus piscivorus, the true ‘water moccasin,’ or ‘cotton mouth.’ At the time of writing there are examples of both these at the Gardens, the harmless ‘moccasin,’ a rather handsome snake, and the venomous one (not there recognised as the well-known moccasin of the United States), so nearly black that we can account for its being occasionally called the ‘black water viper.’

It is probably Tropidonotus which Parker Gilmore describes as ‘water vipers.’[73] At Vincennes in Indiana, he says, ‘On the side where some alder bushes grow in the water, I have seen, on a very warm and bright day, such numbers of water vipers twined round the limbs and trunks which margin the pond, that it would be almost impossible to wade a yard without being within reach of one of them. They certainly have all the appearance of being venomous; the inhabitants say, however, they are harmless. They feed principally on fish, frogs, and small birds.’

Of American water snakes, the anaconda deserves special mention. Of it Seba says, ‘Ce serpent habite plus les eaux que les rochers;’ and in its having the nostrils situated on the top of the head, and in possessing some other features in common with the HomalopsidÆ, we are justified in calling it a water serpent, notwithstanding it is a true constrictor. ‘Mother of waters,’ the aborigines of South America call it. It is the Boa aquatica of Neuwied, and Eunectes murinus of Wagler, the latter name being the one most frequently used by modern herpetologists. Dumeril adopts it, l’Eunect murin, giving the origin of the generic name, bon nageur, from the Greek e?, bien, fort, and ???t??, nageur—qui nage bien. As to the meaning of the specific name murinus, there can be but little doubt, though some have attributed it to its mouse-coloured skin or spots. Le mangeur de rats, Bonnat called it; le rativoro, LacepÈde. Seba, who was one of the first to describe it, says, ‘Il font guerre aux rats;’ and Bonnat, on his authority, says, ‘Il se nourrit d’une espÈce de rats.’ ‘Serpent d’Amerique À moucheteur de tortue,’ Seba also describes it, and with ‘jolies Écailles magnifiquement madrÉes de grandes taches, semblable de celles des tortues; taches semÉes sans ordres, grands, petits,’ etc. Murinus, therefore, clearly refers to its food, not its colour.

Dumeril’s description is of more scientific exactness: ‘Pas de fossettes aux lÈvres. On peut aisÉment reconnaitre les Eunectes seul entre les boa, ils ont les narines percÉes À la face supÉrieure du bout du museau et directement tournÉes vers le ciel.’ These, being extremely small, and with a power to close hermetically, declare its aquatic habits. Its eyes are prominent, and so placed that the reptile can see before it, and also below—that is, down into the waters.

On first sight it might be a matter of wonder that so large a serpent should condescend to a meal of rats and mice; but to explain this we must again go back to the early naturalists, when we discover that what Seba called le rat d’Amerique was a rodent quite worth constricting for dinner. Under the order MuridÆ were included in those days a number of the larger rodents, such as the Paca, Mus Braziliensis; the Coypu, Mus coypus; Myopotamus, the Capybara; the Murine opossum, and several others, aquatic in their habits, and large enough to attract the ‘Giant of the Waters.’

From the vernacular Matatoro, or ‘Bull killer,’ also a whole century of misrepresentations have arisen, the said ‘bull’ being really as small in proportion as the ‘rats’ and ‘mice’ were large. ‘The deer swallower’ is another of its local titles, showing that it is a serpent of varying tastes. Stories are told of this ‘monster’ killing itself in attempting to gorge large animals with enormously extended horns, animals not to be found among the Brazilian fauna; and familiar to most persons are the illustrations of anacondas of untraceable length, the posterior portion coiled round a branch fifty feet high, and the anterior coiled round a bull as big as a prize ox. These illustrations are the offspring of ignorance rather than reality, and though occasionally Eunectes might come to grief by attacking a somewhat unmanageable meal, yet its recognised specific, murinus or murina, points more clearly the true nature of its food, viz. rodents of at most some two feet long.

No less exaggerated than its appetite is its length. Possibly anacondas may have attained greater size formerly when there were fewer enemies than at present, if it be true, as some have affirmed, that serpents grow all their lives. Thirty feet is the utmost length on record. Wallace affirms that he has never seen one exceeding twenty feet. Those individuals at the Zoological Gardens have rarely exceeded this, and GÜnther gives twenty-two feet as their average length in the present day.

Of those known in South Africa as ‘water snakes,’ one is Avusamans vernacularly, a black one and common, and another, Iffulu, of a beautiful bright green. Mr. Woodward, whose scientific egg-sucker has been already mentioned in chap. iii., states that both these are poisonous, that he never saw the green one out of water, and that it is unsafe to bathe where they are. On referring to Dr. Andrew Smith’s Zoology of South Africa, I am not able to identify these with certainty, and do not, therefore, give the above as scientific information.

But before concluding this part of the subject, I would add a word or two on the importance of an accurate description of the snake, as far as possible, when one is found in some unusual situation; because a snake being found in the water is no proof that it is a water snake, or even that it was there by choice. Livingstone, in his Expedition to the Zambesi, p. 150, describes the number of venomous creatures, such as scorpions, centipedes, etc., that were found on board, ‘having been brought into the ship with wood.’ ‘Snakes also came sometimes with the wood, but oftener floated down the river to us, climbing easily by the chain cable. Some poisonous ones were caught in the cabin. A green one was there several weeks, hiding in the daytime.’

Often in newspapers are stories of ‘sea snakes’ as having appeared quite out of their geographical range. These on investigation may reasonably be traced to land snakes which have been carried out by the tidal rivers. In Land and Water of Jan. 5, 1878, was such a story. Again, March 31, the following year, a correspondent, ‘J. J. A.,’ on ‘Animal Life in New Caledonia,’ stated that the sea inside the reefs is sometimes covered with both dead and living creatures carried out by the violence of the currents after heavy rains. ‘The flooded rivers rush with great force from the mountains,’ and numbers of reptiles were among the victims of that force. He saw ‘incredible numbers of snakes,’ and described the common sea snakes as ‘stupid, fearless things, that will not get out of your way.... The small sand-islands are literally alive with them.’ The writer made no pretensions to be a naturalist, or to state confidently what the snakes were specifically. New Caledonia would seem to be rather beyond the range of sea snakes proper, and those ‘incredible numbers’ may have been only land snakes involuntarily taking a sea bath, or certain species frequenting brackish waters, like those in South Carolina described by Lawson.

About the same time an American newspaper contained an account given by Captain O. A. Pitfield, of the steamship Mexico, who stated that he had ‘passed through a tangled mass of snakes’ off the Tortuga islands, at the entrance to the Gulf of Mexico. The ship was ‘more than an hour’ in passing them. ‘They were of all sizes, from the ordinary green water snake of two feet long, to monsters, genuine “sea serpents,” of fourteen to fifteen feet in length.’ I replied to both these communications at the time (Land and Water, April 5, 1879), inviting further information, and describing the features by which true water and true sea snakes could be easily distinguished. Nothing further appeared on the subject, and I have little doubt but that, in both cases, the ‘shoals of sea snakes’ were land species that had been merely carried out to sea by force of rivers. I have since been more strongly inclined to this opinion on learning from Dr. Stradling that similar transportations of snakes occur through the force of some of the South American rivers. ‘Do you know the snakes which belong to the River Plate proper?’ he asks me by letter. ‘So many are brought down by floods from Paraguay—even the big constrictors—that it is difficult to determine from occasional specimens.’

I could not, unfortunately, refer to any books that afforded much information on this subject; for amongst the greatest literary needs experienced by an ophiologist is some complete and special work on the South American snakes, corresponding with GÜnther’s Reptiles of British India, and Krefft’s Snakes of Australia.

Other writers have mentioned the occurrence of boa constrictors and anacondas far out at sea occasionally, beguiling the unsophisticated into reporting a veritable ‘sea serpent’ to the Times by the first homeward-bound mail.