Snakes: Curiosities and Wonders of Serpent Life

by Catherine Cooper Hopley

To recapitulate the above in a few words—first, respiration warms the blood; snakes are cold-blooded because only a portion of the blood passes through the lungs to become oxygenated, and in proportion to the diminution of the quantity of blood transmitted to the lungs, so does respiration become weaker; therefore reptiles are less dependent on breathing.

Regarding the ‘voice’ of serpents, so surprising are the qualities attributed to it, that one would imagine the existence of varieties of snakes of widely differing organizations, if we were to believe all we read of the sounds they produce. ‘Hissing loudly,’ or ‘whistling,’ is the rule. No ordinary writer or traveller who says a word about a snake ever heard it hiss anything but ‘loudly,’ a statement traceable to the same sentiment which causes persons to talk of the ‘horrid forked tongue.’ A benevolently-disposed snake who would warn you away with that terrible tongue would also strengthen his argument by a prolonged hiss, and the louder the better.

But let us turn to the hard, cold, unpoetical, unimaginative language of science, and see what a snake can really do in the vocal expression of its feelings.

Says Dr. Carpenter: ‘In all air-breathing vertebrata the production of sound depends upon the passage of air through a certain portion of the respiratory tube, which is so constructed as to set the air in vibration. In reptiles and mammals it is at the point where the windpipe opens into the front of the pharynx, that this vibrating apparatus is situated. Few of the animals of the former class, however, can produce any other sound than a hiss, occasioned by the passage of air through the narrow chink by which the trachea communicates with the pharynx; but this sound, owing to the great capacity of their lungs, is often very much prolonged’ (Animal Physiology),—prolonged, but not powerful, be it observed.

Says Professor Owen: ‘The true “chordæ vocales” are absent in serpents, and the voice is reduced to a hissing sound, produced by the action of the expired air upon the margins of the glottis’ (Anatomy of the Vertebrates).

Speaking of the escape of air from the lungs, Dumeril says: ‘Lorsqu’il est passé plus vivement il laisse entendre une sorte de vibration, qui le plus souvent, ne consiste que dans le bruit d’un soufflement.’[40]

Sometimes, according to the position of a snake, or when the passage is well open and uninterrupted, the hiss partakes somewhat of a whistling sound, like the blowing through a quill. I observed this particularly in a ‘tree boa’ (Epicratis cenchris), which hissed at me angrily one day because I took the liberty of touching it when the keeper opened its cage to arrange its blanket. The ‘hiss,’ not loud, or by any means musical, differed from the ordinary blowing only as a current of air passing through a round tube would differ from the same current passing through a narrow slit. A true ‘hiss,’ such as we produce with closed teeth in prolonging the sound of s, a serpent can never express. The nearest approach to it in the human voice is when the tongue is in the position as if we are about to say ye or he, and then prolong the breath; that is to say, breathe out while the tongue is so placed before the word is uttered.

Naturally the larger the snake the stronger the ‘hiss;’ the more rapid the expiration, the more powerful will be the volume of air with its attendant soufflement.

The sound and action, as well as degree, are easily seen in the ‘puff adder’ (Clotho, or Vipera arietans). When angry or alarmed, it draws in a full breath, and its body swells perceptibly; then you hear the escaping air like a prolonged sigh or blowing till the lungs are empty. This process is repeated as long as the provocation lasts.

These alternate inspirations and expirations, with their accompanying movements, the swelling and then diminishing of the trunk and the regular soufflants, are so precisely like those of a pair of bellows, that excepting in shape, we require no more complete comparison. The degree or strength of hiss is in this reptile very perceptible. When recently imported and easily excited, its violent ‘puffing’ corresponds with a very large pair of bellows; but in time it grows less alarmed at the appearance of the human beings who unceremoniously stare at it; and at length the puffing is very slight, ceasing altogether after the snake becomes accustomed to its surroundings. But if molested and alarmed, you then see the full play of the lungs, and the whole body alternately expanding and contracting as before.