Evolution of the Human Jaw

man with hand on jaw

Many believe that individuals with underbites have weak jaws. Others believe that the human jaw is naturally weak in comparison to the jaws of a shark, dog, or even a cat. Although a human jaw may not appear to be as strong as the jaws of other mammals, it is quite powerful. Exactly how strong is the human jaw? Our team at Lake Forest Dental Arts explores this topic.

The Human Bite vs. the Animal Bite

Most measurements regarding the strength of the human bite are based on two-dimensional models. In actuality, your jaw works in three-dimensions. Dr. Stephen Wroe, from the University of New South Wales, created a signature technique to fabricate models of animal skulls, in an effort to measure the power of their bites.

The technique Dr. Wroe used was referred to as finite element analysis, a similar technique utilized by engineers when they test the properties of machines and vehicles. After testing the virtual model of the human skull, it was revealed that the second molar in the jaw of humans can exert a bite force from 1,100 to 1,300 Newtons.

Although the human skull is relatively light, scientists have found that our jaws are approximately 40 percent more efficient than that of a chimp, gorilla, an orangutan, and two prehistoric members of the “Australopithecus africanus” and “Paranthropus boisei” family.

With this new revelation, there is now a sound explanation as to why our skulls are not as forceful as our prehistoric ancestors given our skulls are not as stressed. These new findings have now provided insight as to why our tooth enamel is so dense.

How did the Human Jaw Decrease in Size?

Scientists believe that the size of the human jaw centered around the fact that early humans processed their foods. This means that researchers believe that prehistoric humans are cut their food into more manageable pieces, and mashed their foods for easy consumption. Without large pieces of food that needed immense chewing, the prehistoric humans did not need a large jaw.

Researchers further believe that we have less teeth than early humans too. For example, wisdom teeth are now considered functionless compared to early humans, when they were necessary to chew food.  Since the human jaw size decreased throughout evolution, there is not enough room in the jaws of many individuals, to have comfortable fitting molars. Wisdom teeth were a necessity in early times, but have evolved into teeth that have no real function.

The Evolution of Teeth

Additional research indicates that not only did the human jaw shrink over time, but so did the number of individual human teeth.  While human molars pre-molars, and bicuspids are still larger and flatter than our canine teeth or incisors, they are still smaller than the teeth of prehistoric humans.

In prehistoric times, those teeth were thought to be teeth used to ground up and process grains and vegetables to eat. Then, once those early humans figured out how to use other tools to cut and mash food, the teeth less work and tools were used to process foods. Those large flat teeth were replaced with early utensils.

Problems with the Jaw

Even though our jaws may be mighty, they are susceptible to injury and damage. Just like with other parts of the body, we must take care of our jaws when issues arise. Although no one ever thinks about his/her jaw until there is a problem, there are disorders of the jaw that may need medical attention.

Additional Facts about the Human Jaw

Understanding the jaw for better health is not only imperative, but can prove to be fascinating. Here are some additional facts about the human jaw:

  • One of the bones of the human body that does lots of work for us is our jaw or mandible.
  • We use our jaw every day.
  • Our jaws not only help with eating and chewing, but with speaking and articulating words.
  • Researchers found a jawbone believed to be 2.8-million-years-old, in Ethiopia. That finding is now thought to be the earliest ancient human fossil ever found.
  • The lower mandible or jawbone is the strongest bone in the human skull.