Snakes: Curiosities and Wonders of Serpent Life

by Catherine Cooper Hopley

Illustration of eye covering.

For the process of sloughing or casting the skin, the term desquamation—literally, an unscaling—is often used; but this word seems rather to imply an unhealthy action, as if the cuticle peels off in pieces, than the normal operation, which is to shed it entire.

It is a matter of surprise—if we are to believe what we read—that few naturalists seem to have witnessed this process, so as to be able to describe it from their own observations; but this must be due more to lack of interest than of opportunity, since the occurrence is very frequent. Those in the vicinity of Zoological Gardens have no excuse for not observing it; yet so lately as Oct. 1879, we find a writer in Nature, vol. xx. p. 530, attempting to describe the ‘skin-shedding,’ with the admission that he has never witnessed the process, nor, he believes, ‘has any observer’! He thinks snakes shed the skin ‘as if you turned a narrow hem, or a glove-finger by a knotted thread fastened at the tip,’ and which of course would draw the tip inside the finger. The glove tip is to represent the tail of the snake, which, as he supposes, adhering at the tip, is drawn along inwards as the snake proceeds to crawl out of its own mouth, or its cuticle’s mouth—which has already become loosened round the lips. This, in the mind of that writer, satisfactorily accounts for the skin being usually found reversed! Can he have never seen a silkworm change its skin; or found the slough of a common caterpillar adhering to its tail; or observed the appearance of its mouth previous to the moulting? True, a slow-worm sometimes leaves its slough in a crumpled-up condition, exactly like the silk-worm’s. This I have seen. On the other hand, the same little reptile, on another occasion, crawled out of its coat, leaving it perfect and unreversed through its entire length. Both sloughs have been preserved. As a more general rule the slough is reversed; but in the process it folds back and over the body, outside of it, in the manner of a stocking drawn off from knee-wards, and turning back till entirely reversed it leaves the foot. This common and apt illustration is easily understood if we suppose the top of the stocking to be the mouth of the slough, and the toe its tail. But as the toes might sometimes slip out of a stocking when nearly off, so does the tail of a snake sometimes slip out; this portion therefore is often found unreversed. More than a hundred years ago the sloughing of snakes was understood and described in the Phil. Trans. for 1747, vol. xl.; as also of lizards ‘slipping off their skins as vipers do.’ Some young vipers changed at six weeks old, and again in two months after that. ‘They always began at the mouth,’ said the writer. The process has been witnessed and described by many since that, though more by foreign than by English naturalists.

Some of the older writers have told us that ‘a snake frequents the spot where it has cast its skin,’ or, in other words, that it selects that locality for its nest—a fact as curiously stated as if you related of a person that he chose for his home the house in which he performed his toilet. Snakes have a strong affection for locality; and where their nest is, there, or near it, their garments are naturally renewed.

Another mooted question has been the precise period of sloughing; formerly the accepted opinion was that once a year, viz. in the spring, was the usual habit. This was probably from so many coils of skins being found at this season. That they do change in the spring may be established as an almost invariable rule; but not then only. No precise periods can be given with certainty, because it depends on the individual, its health and surroundings. The ophidian is a fastidious creature, and when his garment becomes soiled or uncomfortable he discards it. Thus after hibernation, when for some months numbers of snakes have been coiled in masses in a cave or under stones and rubbish, and they emerge into daylight, aroused by the sun’s revivifying rays, what more natural than to cast off the old winter garb for a more comfortable suit?

Almost invariably, soon after a long journey, and on being established in a new home, a snake re-attires. We have seen what their travelling cages are! Closely nailed up, and often in air-tight boxes in which the poor things are tumbled over and over with as little mercy as ceremony during removal from one conveyance to another, they arrive—as in the case of the African viper (coloured illustration)—in such a pitiable plight that it is next to impossible to identify them. Another almost invariable rule is sloughing soon after birth—that is, in from a week to a fortnight; also, during early and rapid growth, the young snake will change frequently. Most ophiologists fix upon two months as an average time, taking one snake with another; for while one may desquamate every few weeks, another may keep his coat unsoiled for six months.

Sir Joseph Fayrer made careful notes on this subject. He had one cobra which changed in rather less than a month—viz. first on Oct. 17th, next on Nov. 10th, and again on Dec. 7th. A Liophis at the London Gardens changed every few weeks, and a Ptyas—he of the lecture exhibition (p. 214)—changed almost once a month on an average.

A curiously beautiful object is the cast-off coat, and well worth an examination. You discern the exact form of the reptile’s head, mouth, and nostrils, the exquisitely transparent eye-covering, the various forms of the overlapping or imbricated folds or ‘scales,’ and how admirably the broad ventral plates are adapted for locomotion; particularly noteworthy too is the perfect reversion of this coat of some feet or some yards in length, turned inside out as you may turn a sleeve.