Snakes: Curiosities and Wonders of Serpent Life

by Catherine Cooper Hopley

After becoming better acquainted with the nature of that tube which had impressed me so strangely, I lost no opportunity of making further observations, and on the following feeding day at the Gardens I saw the air-tubes of several snakes plainly. In September of that year, a new ‘Horseshoe’ snake (Zamenis hippocrepis) arrived from Morocco. It was a small and very pretty snake, and while enjoying the privilege of a private inspection, the keeper got its mouth open for me, enabling me to see the glottis, as well as to both see and feel the four upper rows of its beautiful little teeth, closely placed, and as sharp as the finest pins. But the action of the air-tube was very distinct. Probably little Zamenis was breathing harder and nervously under the detention, but no word better describes the formation of the aperture of the perfectly rounded tube, and the movement of it, than the petite languette.

Subsequently, there were opportunities of observing the air-tube in two of the large African vipers, the ‘River Jack’ or ‘Nose-horned’ vipers (Vipera rhinosceros) occupying the same cage. Each struck a guinea-pig and held it. One of them began to eat his before it was quite dead, and had finished it before his friend had begun. In his case, the air-pipe was at the side of his distended jaws. In the other, it projected more than half an inch beneath, nearly in the centre.

This happened on a mild, damp day in November 1873, and after that I saw the tube in ‘several snakes,’ but I regret the names were not entered in my notebook at the time. In the smaller non-venomous snakes, or in the lacertines—of which there were then a large number—I do not remember to have observed it. They despatch their frog or mouse so quickly that they would scarcely need a fresh supply of air meanwhile. In the larger vipers, rattlesnakes, and constrictors, the air-tube was undoubtedly witnessed. Winter then terminated my observations, and afterwards a prolonged absence from town. Unfortunately, when observations were about to be resumed, the change of the plans at the Zoological Gardens, and the exclusion of the public, defeated my intentions, though on one occasion I did see the windpipe of little Natrix torquata very distinctly; and this was the smallest snake in which I had ever observed it. Natrix had nearly disposed of a large frog. The whole of it was in his mouth, which was widely expanded, and the air-tube was protruded sideways, not out of the mouth, but sufficiently forward to enable one to distinguish its form, and the action of the petite languette. The prey being unusually large, the snake had needed air while swallowing it.

On several occasions in snakes recently dead, and of various sizes, one has been able to notice how admirably this tube, which lies along the mouth like a soft cushion, somewhat in the form of a parrot’s tongue, is supplied with space in the roof, arched to fit it, the palate teeth enclosing it on each side, while the opening, or glottis, exactly meets the nostrils, les arrières nez, bringing it into communication with the outer air.

In a little Coluber, just dead, I again had an opportunity of making observations. The membranous coating was so thin and transparent that the rings of the windpipe could be very distinctly traced from a quite forward position in the mouth, and beginning on and over the tongue sheath. The surrounding skin or membrane was also loose and abundant, so that with the point of a needle the upper part of the windpipe could be easily drawn forward beyond the lips. In life the little snake could thus have voluntarily protruded it as occasion required.

Another day the large reticulated python seemed to intentionally gratify my curiosity by affording me a most leisurely and excellent opportunity for observation. His head was raised, and so close to the glass that the process of swallowing could be watched conveniently. The final swallow, or successive efforts at the last were, as usual, attended with frequent yawns. The glottis, as could on these occasions be distinctly seen, was repeatedly opened and closed, and after being extended beyond the mouth, it gradually resumed its natural position. While the prey occupied the entire space between the gaping jaws, one could see the air-tube pushed forward beneath; but as by degrees the duck disappeared down the throat, the interior of the mouth could be better and better observed. In this large snake the membrane or skin was too thick to enable one to discern rings as in the little Coluber; but as the larynx is merely the upper part of the trachea, and as the glottis is the mere membranous opening to the larynx, it seems evident that the windpipe itself is also extensible, the windpipe being, indeed, the only portion of the air-tube sufficiently firm and resisting to aid the purpose of respiration under such conditions.

The exact distance which the tube is extended cannot be accurately stated. It would not be equally protruded in snakes of different sizes nor under different conditions. Broderip saw it ‘as much as a quarter of an inch.’ Bingley, an earlier and a less safe authority, says ‘the windpipe projected three inches beyond his jaws.’ The keeper at the Gardens thought he had sometimes seen it ‘as much as two inches in the largest snakes;’ and my own impression was, one inch, at least, in the python, and almost that in the large vipers.

It is undoubtedly one of those interesting features worthy of further investigation, and one is surprised that more accurate information regarding it has not appeared in our later encyclopedias and in the ‘Proceedings of the Zoological Societies.’

So long ago as 1826, it was observed and confirmed by the distinguished author of Zoological Researches, and Leaves from the Notebook of a Naturalist. The author of British Reptiles, who conducted the Zoological Journal when Mr. Broderip contributed the valuable paper above quoted, added a note by special request, stating that his own ‘not unfrequent observations have on every point been completely confirmatory of those above recorded’ by W. J. Broderip, Esq.