Chimp "Dinner Conversation" Proof of Ape Speech?

Adrianne Appel
for National Geographic News
October 20, 2005

Scientists say they have discovered the first evidence that chimpanzees speak to each other about objects in their environment.

Chimps at the Edinburgh Zoo in Scotland use a crude language of grunts to talk to each other about their food, say primate experts at the University of St. Andrews in Scotland.

The chimps utter high-pitched noises (hear the audio) or low-pitched grunts (hear the audio) to tell each other about the food they find in their pen, the researchers say.

The finding could lead to better understanding of the origins of human speech, the scientists say.

Previous studies have found that monkeys, as opposed to apes, communicate with each other through sound about events in their environment and that great apes can use hand signals. The new chimp finding, however, may be the first evidence of great apes using vocal communication.

Humankind's closest genetic relatives, the great apes include gorillas, chimpanzees, and orangutans.

Bread Good, Apples Bad

At the Edinburgh Zoo the chimps make high grunting noises when they find bread, a food they seem to like, and low grunting sounds when they find apples, which they apparently don't care for very much, according to the study, published last week in the journal Current Biology.

After noting the different types of grunts, the researchers set out to see if other chimps listening to the grunts interpreted them the way the researchers had ("bread" and "apple"). The researchers found that the listening chimp did seem to understand what the grunts mean.

The scientists recorded the grunts and played them to a chimp in the pen. When the chimp heard the "bread" grunt, the ape looked in the place in the pen where bread is usually found. When the "apple" call was played, the chimp searched appropriately for an apple.

"It shows that, by simply listening to each other's calls, chimpanzees can infer what kind of food the caller has found," said researcher Katie Slocombe, who worked with colleague Klaus Zuberbuhler on the project.

More Experiments Planned

Continued on Next Page >>


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