Air Date: Week of May 9, 2008

Chimps like carb-heavy comfort foods like yams and potatoes, and scientists have discovered they use tools to get to them. Alexandra Gutierrez reports.

Transcript

GELLERMAN: Just ahead – we talk trash. But first, this note on emerging science from Alexandra Guttierrez.

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GUTIERREZ: Humans find foods like baked potatoes and yams particularly comforting. New scientific discoveries suggest that our nearest primate relatives, the chimpanzees, share our taste for these vegetables.

A team of anthropologists say they've found evidence from Western Tanzania that chimps use tools to dig for roots and tubers. A University of Southern California researcher studying chimp behavior found dirt-covered sticks and knuckle prints in the mud at numerous sites.

This was a surprise, as humans were thought to be the only species that used tools to dig up root vegetables. Not only that, it suggests the chimps search out tasty tubers during the rainy season when food is plentiful. Most researchers previously thought the chimps relied on roots only during the hungry dry season.

The team believes this finding may also shed light on the diet of our ancient hominid ancestors who roamed the savannah three and a half million years ago. Anthropologists say the teeth and jaws of these ancestral humans changed to enable them to chew tougher food. Scientists claim these developments reflect dietary changes, and many think it shows the critical importance of hunting and meat eating for early humans. But this team argues that the new discoveries suggest early humans enjoyed a mixed and varied diet, including roots rich in carbohydrates.

One intriguing fact: the modern chimps are eating roots that African hunter-gatherers today only use as medicines, suggesting that our nearest relatives understand how to eat to keep themselves healthy. Perhaps there's a lesson there for us modern humans.

That's this week's note on emerging science. I'm Alexandra Gutierrez.

GELLERMAN: Coming up – the fuel crisis. The light at the end of the tunnel could be a train. Just ahead on Living on Earth.

ANNOUNCER: Support for the Environmental Health Desk at Living on Earth comes from the Cedar Tree Foundation. Support also comes from the Richard and Rhoda Goldman fund for coverage of population and the environment. This is Living on Earth on PRI: Public Radio International.