Walk Softly: Jaws vs. Anaconda II

by Geoffrey Carpentier

In the last column, we explored the lives of some amphibians and discovered they use a variety of techniques to capture and subdue prey. This time let’s look at their reptilian cousins to see how they cope.

Reptiles have additional techniques to capture their prey. They don’t use the sticky tongue technique but rather grab and hold their prey, before taking the next step to subdue, hold or eat it. Many snakes have backward pointing teeth which are not designed for tearing or shredding prey but rather act like tiny hooks, to hold the prey, while the snake uses contractions to slowly pull it into its mouth and eventually to the stomach.

Now is a good time to dispel a widely touted myth, 'Snakes dislocate their jaws so they can eat large prey.' NOT TRUE! Snakes have a morphological adaptation, whereby, their lower jaw is split into two independent segments, allowing snakes to stretch the jaw almost 180 degrees from the resting position. Aiding this ability is a flexible quadrate bone, at the back of the mouth, and joined to the base of the skull with large, strong ligaments, adding to the flexibility of the jaw.

All quadrupeds (four-legged animals) have a quadrate bone, but it has been adapted to serve various purposes in different animals. In humans and other mammals, for example, the quadrate bone has been adapted to become a part of our inner ear. A snake’s quadrate bone is also connected to a snake’s inner ear and is instrumental in hearing, but its primary purpose is in food capture.

Snakes lack outer ears and eardrums, so they can’t hear many sounds, but they are sensitive to low-frequency sounds. By keeping their head close to the ground, they can detect low-frequency sounds, such as a rodent’s footstep, for example, through their lower jaw via their quadrate bone.

While we’re talking about snakes, if they eat large prey (bigger than their mouth) how do they breathe? Simple – many snakes can extend the breathing tube (i.e. the glottis) outside the mouth while swallowing and this allows them to eat and breathe at the same time!

Let’s look at some bigger reptiles. Crocodiles and alligators have huge mouths which can open extremely wide. Their jaws have immense power and can snap closed, lightning fast, grasping prey in a death hold. Their typical technique is to hold the prey, drag it underwater and roll over repeatedly, to start to break it into bite size chunks and then swallow it. The large and numerous teeth help with both grasping their prey and tearing it apart. Monitor lizards are a large family, of mostly African and Asian lizards (e.g. Komodo Dragon), which eat everything from fruit to birds, turtle eggs and carrion. Their mouths have bony ridges which help grasp and hold prey along with a unique type of tooth structure. Their teeth are often pointed, uniformly recurved and laterally compressed, allowing the monitor lizards to tear off chunks of meat from their prey. As the lizards mature, they develop wider and blunter posterior teeth, allowing them to effectively crush prey.

Many herptiles are venomous, and they utilize this weapon in different ways. Some snakes have hollow fangs to inject their prey with venom, as we all know. Though monitor lizards are venomous, their venom is not deadly like that of some snakes and spiders. Most species of monitor lizards have venom glands in the lower jaws. They do not have fangs, but instead, monitor lizards mix their venom with saliva which is delivered in a bite from their sharp, blade-like teeth. Their venom has either anticoagulant properties which inhibit the clotting of the prey’s blood, or it contains neurotoxins which can lead to paralysis.

Correction: In a previous column, I incorrectly indicated our Snapping Turtle has an appendage in its mouth which it uses to lure prey, so the turtle can catch and eat it. The reference should have stipulated, the Alligator Snapping Turtle does have this appendage in its mouth, but ours doesn’t. Next time we’ll look at birds, to see how they cope.

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