Before the days of soy milk lattes and green coloured smoothies, our ancestors had to forage, gather and hunt for the foods they used to fuel themselves daily. Although those days are long gone, the evolutionary process that allowed us to survive and thrive in those times still has its fingerprints all over the jaw and tooth structure we have in our mouths today.
Although the human bite is rarely tested from a standpoint of brute strength and force (our sympathies to Evander Holyfield), the truth of the matter is that when the time calls for it, our bites can be extremely potent. It seems that all those eons spent using our teeth to get through thick and thin has helped develop an efficient and effective bite that we never seem to have lost.
According to a recent study by Stephen Wroe of the University of New South Wales in Sydney, Australia, it was a long held belief within the scientific community that the advance of modern food preparation and cooking no longer required humans to pack the same power per bite. This theory was supported by the fact that our jaw muscles and skulls are both smaller in size and weight than those of both our fossilized descendants and living great ape relatives.
The fact that there was no conclusive or direct data to support such findings intrigued Wroe, who decided to form a team to study just how powerful the human bite was relative to hominids across time as well as our powerful and existent ape brethren. With the use of advanced engineering software the maximum bite force of modern humans (could be your neighbours for all you know), chimpanzees, gorillas, orangutans and gibbons were compared to those of two fossil hominids (Australopithecus africanus and Paranthropus boisei aka “nut-cracker man”). The latter two existed 3.03 million and 2.3 million years ago respectively.
Using a method known as 3D finite element analysis on CAT-scanned models, each skull was simulated biting a common hard object with the rear teeth in order to study how the force and stress was distributed. It turns out that the human jaw although relatively small was far and away the most efficient of the lot.
“When you actually look at the mechanics of it, the human jaw is highly efficient,” said Wroe. “For any given bite force you want, we can achieve it with much less muscle.”
This efficient design allows our jaws to be 40 to 50% more efficient than each of the great apes meaning that pound for pound our sandwich snap is harder than anything a chimp or gorilla can muster.. Have a laugh about it the next time you’re at the zoo.
In terms of historical context, our bite was right on par with that of nut-cracker man with body size and weight taken into consideration. The distinctive feature it seems is leverage, determined by how long our jaw is as well as how our jaw muscles are arranged at the fulcrum. It seems that the lack in size as compared to chimps doesn’t impact our single strongest bite but does for our ability to chew and bite forcefully over time as would be required for tough leaves and bamboo tubers.
Sources: Discovery News