Adventurous Eating Helped Human Ancestors Boost Odds Of Survival

By Nancy Shute

Published November 13, 2012 at 11:12 AM CST

The first prehistoric chef who looked out at a field of grass in Africa and said, "dinner!" may have helped our ancestors use new resources in new locations.

Picture, if you can, a prehistoric Bobby Flay — an inventive 3 million-year-old version of the Food Network star chef. He's struggling to liven up yet another salad of herbs and twigs when inspiration strikes. "We've got grass here, and sedge," he says. "Grass and sedge, that's what this dish needs!"

His pals take a tentative taste of this nouvelle cuisine. Sedges usually aren't considered gourmet fare, after all, by these human ancestors. They're tough grasslike plants that grow in marshes. But wow! Not only is this a new taste sensation, it's found in many places.

This kind of discovery of new foods may have upped the odds of survival for human ancestors, archeologists say in a new paper.

Archaeologists are intensely interested in what those ancestors ate, and how changes in the diet may have influenced how we became humans.

By analyzing the carbon in fossil teeth of Australopithecus bahrelghazi, a hominin that lived about 3 million years ago in what is now Chad, scientists were able to figure out that they ate grasses and sedge, not the bush-and-herb diet typical of early primates, or today's great apes.

It's progress, but was it tasty? Probably not, says Julia Lee-Thorp. "Bleah. That's about the right response." They also weren't very nutritious, adds Lee-Thorp, a professor of archeology at the University of Oxford in England, who led the new research. Her report is published in the Proceedings of the National Academy of Sciences.

That hasn't discouraged fans of the paleo diet, who argue that eating these so-called C4 plants — corn and grasses that typically grow in warmer savanna climates and are named for the way that plants fix carbon as they photosynthesize— are a lot healthier than plants that make the C3 form of carbon. C3 plants include beans, rice, and potatoes.

Broadening their diet to include a variety of plants may have made it more likely that these early primates could expand into new territory. "It's possible that they were driven" to eat new foods, Lee-Thorp tells The Salt. "But it's more likely that this was a new niche, a new opportunity that arose. "

So dietary adventures could have led early human ancestors on the first steps of migrations through Africa and beyond.

Corrected: November 13, 2012 at 11:00 PM CST

C4 plants are named for the way the plants fix carbon as they photosynthesize, not for the isotopes used to identify them. The text has been corrected.