Mastication adaptation: easier chewing helped human ancestors evolve

A study in which people chewed on pieces of raw goat meat and vegetables smacked with a rock is shedding light on how changes long ago in the way our ancestors dined paved the way for evolutionary advances that helped make us who were are today.

Scientists said on Wednesday the advent of meat-eating combined with the use of simple tone tools to make food easier to consume meant that members of the human lineage about 2.5 million years ago all of a sudden had less need for chewing.

Without needing to spend much of the day chewing food as chimpanzees do, our ancestors underwent significant evolutionary changes, acquiring smaller teeth, jaws and chewing muscles while losing the snout possessed by their predecessors.

“Shortening the snout might have been beneficial for producing articulate speech, for having a more balanced head, especially useful when running, or perhaps for other reasons,” Harvard University evolutionary anthropologist Daniel Lieberman said.

The changes also may have enabled the development of larger brains in early human species like Homo erectus compared to earlier members of the human lineage like Australopithecus, who combined ape-like and human-like traits.

Meat compared to plants added a calorically dense food to the diet of these early humans as their brains and bodies got bigger.