Anthropologists have found that the size of a person's teeth and the strength of his bite decreased due to the appearance in the diet of meat processed with the help of stone tools. The study was published in the journal Nature.
The evolution of the genus Homo is not fully understood, but it is known that the brain and body of Homo erectus were larger than that of previous hominids, the brain volume gradually increased, but the teeth became smaller, and the chewing muscles were weaker.
During the early Paleolithic period, Homo began to make tools. Archaeological and paleontological finds indicate that humans began to consume meat about 2.6 million years ago, and heat treatment of food appeared 2 million years later.
Despite the importance of meat consumption, little was known until the present study exactly how meat and meat processing influenced chewing apparatus modification. It is known that Australopithecines ate a lot of plant foods, and this required thorough chewing and a large expenditure of energy for food.
Scientists conducted an experiment in which adults were fed standard portions of meat (they used goat meat, since it is tough and more like wild animal meat than beef), as well as sweet potatoes, carrots and beets. The products were either not processed at all, or only slightly processed. Using electromyography, a method of studying the bioelectric potentials that arise when muscle fibers are excited, the researchers compared how much force the subjects exerted to chew different foods.
It has been found that eating unprocessed meat requires less effort than chewing root vegetables. Assuming that meat made up a third of the ancient man's diet, and he used stone tools to process meat and vegetables, people would have to chew 17% less often and use 26% less force, scientists calculated.
Thus, the researchers showed that it was meat and the availability of tools, and not the processing of food with the help of fire, that contributed to a decrease in the face and chewing apparatus of a person, which could lead to the development of speech in the future.