Early Human Ancestors Shifted from Tree Diet to Grass: The Evolution of Taste

Millions of years ago, our early ancestors shifted from a diet based on trees to a diet based on grasses. Now, scientists have taken a closer look at this shift to better understand the array of changes that took place during the Pliocene era, which occurred 2.6 to 5.3 million years ago.

"A refined sense for when the dietary changes took place among early humans, in relation to changes in our ability to be bipedal and terrestrial, will help us understand our evolutionary story," said Naomi E. Levin, lead author of the new study, in a news release.

In this latest study, the researchers analyzed fossil teeth found in Ethiopia. These teeth showed the shift from a diet based on trees and shrubs to one that included grass-based foods, which occurred 3.8 million years ago. That's about 400,000 years earlier than the date supported by previous research.

This shift in diet was extremely important for human evolution. It would have improved our ancestors' capacity for survival and would have allowed them to range wider.

"This research reveals surprising insights into the interactions between morphology and behavior among Pliocene primates," said Yohannes Haile-Selassie, one of the researchers. "The results not only show an earlier start to grass-based food consumption among hominins and baboons but also indicate that form does not always precede function. In the earliest baboons, dietary shift toward grass occurred before its teeth were specialized for grazing."

The researchers actually attribute the dietary expansion to changes in relations among members of the African primate communities, such as the appearance of new species of primates.

The findings reveal a bit more about the evolution of early primates and humans. This may tell researchers a bit more about our roots and how we, as a species, became so successful.

The findings are published in the journal Proceedings of the National Academy of Sciences.

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