[an error occurred while processing this directive]
BBC News
watch One-Minute World News
Last Updated: Tuesday, 13 February 2007, 11:12 GMT
Ancient chimps 'used stone tools'
Tool, PNAS
The tools are 4,300 years old, say researchers
Chimpanzees in West Africa used stone tools to crack nuts 4,300 years ago.

The discovery represents the oldest evidence of tool use by our closest evolutionary relative.

The skill could have been inherited from a common ancestor of chimps and humans, the authors say, or learnt from humans by imitation.

Alternatively, humans and chimps may have developed tool use independently, the Proceedings of the National Academy of Sciences journal reports.

Chimpanzees were first observed using stone tools in the 19th century.

Julio Mercader and colleagues found stone tools at the Noulo site in Ivory Coast, the only known prehistoric chimpanzee settlement.

Nut crunch

The excavated stones showed the hallmarks of use as tools for smashing nuts when compared with ancient human or modern chimpanzee stone tools.

Chimpanzee  Image: BBC
The use of stone tools may have a deep evolutionary origin
Also, several types of starch grains were found on the stones, which the researchers say is residue derived from cracking local nuts.

"Chimpanzee material culture has a long prehistory whose deep roots are only beginning to be uncovered," write the researchers in Proceedings.

The tools were found to be 4,300 years old, which, in human terms, corresponds to the later Stone Age, before the advent of agriculture in the area.

The age of the tools was determined by subjecting charcoal from the same ground layers to the technique of radiocarbon dating.




SEE ALSO
First chimpanzee fossils found
31 Aug 05 |  Science/Nature
Chimpanzee culture 'confirmed'
22 Aug 05 |  Science/Nature
Smart chimps get their reward
24 May 02 |  Science/Nature
Chimps genetically close to humans
20 May 03 |  Science/Nature

RELATED INTERNET LINKS
The BBC is not responsible for the content of external internet sites



FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

PRODUCTS & SERVICES

Americas Africa Europe Middle East South Asia Asia Pacific