T he Agricultural Revolution is one of the most pivotal historical moments in the evolution of the human species. The surpluses of food allowed people to settled down and consolidate, divide labor responsibilities, create a hierarchy of government, and develop currency and uniform trade. In short, it allowed humans to civilize. However, it also have an unintended consequence that is just now being uncovered by anthropologists. Those early farmers, in creating food surpluses, also created an evolutionary trend by which the human jaw became shorter, making people’s teeth for the next 12,000 years crooked. Early farmers also, consequently, created job security for modern orthodontists.

Geneticists and anthropologists have determined that the natural differences in the facial shape and characteristics of people around the world are largely due to “genetic drift”, or random genetic mutations over the course of thousands of years. However, one characteristic that is strikingly similar across the various ethnicities is the shape of our lower jaw. When other genetic modifiers seem to be governed by chance, but another seems consistent, the logical next step is to look at what social and environmental variables may be contributing to the similarity. What does every civilization across the globe have in common? Agriculture.

Some researchers believe that the Agriculture Revolution, which resulted in a change in diet from coarse foods to softer foods, lead to a modification in the lower jaw from a diet requiring less chewing. Noreen von Cramon-Taubadel, a researcher at the University of Kent in the UK, tested the theory by studying the jaws and skulls of 11 ancient populations from all over the world, some agricultural specimens and some hunter-gatherer. What she found was that the farmer’s jaws tended to be wider and shorter, while hunter-gatherer jaws were narrower and longer. In addition, the upper palate of the skulls reflected, to a degree, the shape of the lower jaws as well, while the rest of the cranial shape was unaffected.

After testing these results against historical context; climate variation, geography, and genetic history, von Cramon-Taubadel concluded that it was not until the society had moved from hunting and gathering to farming that jaws began to shorten, becoming weaker and less robust. Research also indicated that this change was not a product of natural selection, but an occurrence of each new infant raised on the diet of softer foods. However, the body continues to produce as many teeth as our larger jaws would accommodate, which is why many of our modern agrarian jaws cram so many crooked teeth into a smaller space.

This begs the question, as we become an increasingly hands off society, are our arms going to shorten and atrophy into little T-Rex-like stubs?