Snakes – A Primer

by Geoffrey Carpentier

Many people fear and loathe snakes, but, if pressed, they wouldn’t even know why. Let’s see if we can learn more about them and their complex development to what they are today.

Historically, the snake’s tubular shape and flexible bones allowed them to persist mostly as subterranean animals which therefore ensured their survival, during, what's referred to as, the Cretaceous extinction which killed most of the dinosaurs. Even though many species have skeletal indications of vestigial leg-like bones, how do they now exist and move without legs? The answer is the adaptation of elongated bodies over time, developing more flexible and numerous vertebrae as they wriggled, to enable movement, instead or walking or running. 

As they moved through the soil the head was prone to damage, so they developed forms of amour to protect the face and body. The external ear canal is closed, so a snake has no ability to hear; the eyes are recessed or protected by supraorbital projections, so many species also have no ability to see, referred to categorically as, simply, Blind Snakes. The nose, as such, is superfluous with respect to the ability to smell which doesn't exist.

As snakes stills need to find food, and they can't rely on auditory clues, so they use their forked tongue which allows them to ‘taste’ the air and read vibrations in the soil around them, to spot prey. In many, the complexities of a thin weakened body presents issues with digestion and respiration. To help with eating food, many species have mechanisms whereby the lower jaw unhinges itself from the upper jaw and the expanded space allows large prey to be consumed. The body, being flexible and expandable, also allows them to take in much larger prey than a thin body structure would normally be able to consume.

A snakes heart is not protected by a breastbone so injury potentially is high and damaging when it occurrs. Their heart is also a single chambered structure, unlike, let's say, reptiles.

Finally, like in the majority of animals, they do not have the more normal complex dual lung system but a single chambered lung, as it fits best in the body.

All this sounds like a design doomed to cause the extinction of all snakes, but history shows something very different. Snakes thrive in all parts of the world except Antarctica and some of the nearby islands. They occupy deserts, rain and temperate forests, mountains, lakes, oceans and just about everything in between! They live in burrows, under rocks, and in trees, caves and myriad other habitats. They truly have adapted to virtually every ecosystem on earth, except permanently ice-bound ones. Not only are they virtually cosmopolitan, but they are incredibly diverse in how they hunt. Many are constrictors which rely on stealth to wait for prey to come close and then they simply suffocate them and slowly consume the entire animal head first. Others pursue their prey with surprising agility and speed, ‘running’ them down. Still others slowly move through habitats, looking for unwary prey, striking out with fangs exposed to poison them.

In any event the outcome is always the same, prey is eaten whole and over a period of days they are slowly digested, as the snake’s enzymes break down their bodies and tissues.

So, there’s a little look into some of the fascinating aspects of snakes! Next time I’ll bring it closer to home.

Geoff Carpentier is a published author, expedition guide and environmental consultant. Visit Geoff on-line on LinkedIn, Facebook and Instagram.