University of Utah researchers used a laser to examine teeth from an early ape-like relative - Paranthropus robustus. The information revealed they migrated seasonally between savannahs and forests.

Thure Cerling, a U. professor of geology and biology, co-wrote a paper in Friday's edition of the journal Science.

Ben Passey, a graduate student and co-author, worked on improving the method to take enamel samples from the ancient teeth without causing undue damage to prized artifacts.

"We're close to the damage level that we think is acceptable," said Cerling.

Passey said he can get a good sample from five brief laser bursts that leave a small crater on the tooth's surface.

As a tooth develops, enamel is added. The enamel contains chemical signatures that are influenced by the user's diet, he said.

In this case, researchers examined different types of carbon found in the enamel. More C13 suggests a grass-based savannah diet. Less C13 indicates a forest diet of leaves, fruits and vegetables, Cerling explained.

Researchers hope the new method will be enough to convince museums to provide them with ancient human teeth to learn about their diets, Cerling said.

The work also holds potential for modern forensics, as law enforcement officials could use such a test to determine if a dead body came from the area it was found or from elsewhere. Even modern diets can provide hints as to where a person lived.