Walk Softly – Jaws vs. King Kong

by Geoffrey Carpentier

Let’s move on to an easy one, mammals. Wait, not so easy, as some mammals are herbivores, others carnivores, and still others are omnivores!

All animals have a mouth which opens wide and has teeth, right? Nope, baleen whales and some other marine mammals do not have teeth but rather have baleen plates. These act like a huge comb which filters food out of a column of water, trapping the prey behind the jaws, so it can be swallowed whole, while water is discarded back into the ocean. Similarly, the Crabeater Seal has modified teeth which act as sieves (like the baleen plates) to filter food out from the ocean.

Okay, are there other mammals without teeth? Yes, anteaters, pangolins, and aardvarks don’t have teeth either.

Anteaters and pangolins use their sticky tongue to catch and subdue prey, relying on grit they have swallowed or strong stomach muscles, to break the food down inside the body.

While aardvarks are born with conventional teeth, they lose them, when quite young, and develop unique, rootless teeth made of tubes, filled with vasodentin (i.e. modified dentin permeated by blood capillaries and common in the teeth of lower vertebrates). These teeth are present in the adults, as peg-like cheek teeth, at the back of the mouth and are not used for chewing, as in most mammals, but rather aid in grinding food on its way to the stomach.

Armadillos use a more traditional means to eat their soft-bodied prey, whereby little chewing is required. So the peg-like, enamel-free teeth of the armadillo act to grind up the prey, before swallowing. Sloths also have teeth, but again, they are modified and serve as a grinding mechanism, to break down tough plant fibres which are the sloth’s primary food source.

Okay so far, we have found, although these animals all have jaws and teeth (for the most part), they all use them differently. Other herbivores (plant-eaters) have jaws and teeth of course, but these do not have to be modified to grasp prey nor tear it apart. They simply must be able to separate the vegetation from the parent plant, by cutting or tearing it, then grinding it up into bite size pieces, to be swallowed. The jaws of these animals are simple, as they don’t have to open very wide nor be very flexible. Many are adapted to move side to side, to facilitate the grinding needed to process their food.

Carnivores, on the other hand, have jaws which primarily move up and down, and they have specially adapted teeth and jaws to allow them to capture and hold prey, often opening wide enough to grasp the throat of the prey to suffocate it, then tearing off large chunks of it to eat, finally chewing or grinding the food into small enough pieces to be swallowed. The power of the jaws of these carnivores is exceptional, as they must both subdue, suffocate, hold, tear flesh and break bones, to allow the predator to fully consume its prey!

Omnivores eat both plants and animals and have a more complex jaw, having to accommodate both tearing and grinding strategies.

Bite Force Quotient (BFQ) is how an animal’s bite strength is measured. A domestic cat has a BFQ of 67, a coyote of 88, 123 for a hyena, a Tasmanian Devil has a BFQ of 181, 1200 for a grizzly and humans’ range between 120 and 160. So, you can see it is quite variable and has a lot to do with the creature’s mass, anatomy, behaviour, the structure of the jaw and what and how they eat.

Just to confuse the picture, the narwhal’s tusk is a highly modified tooth which has nothing to do with eating but may aid in reproduction or assessment of the local environmental conditions.

Oh, my goodness, this is not as simple an analysis as I presumed, when I sat down to write this. Mammals are certainly complex and must adopt a variety of strategies to catch, hold and eat their food. Okay maybe birds are easier! Let’s explore that next time.

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