By Helen Briggs

BBC News science reporter



Tool use in wild chimpanzees (Image: David Bygott)

By training captive chimps to use tools in different ways, they have shown experimentally that primates develop cultural traditions through imitation.

This has long been suspected from observations in the wild, but has not been shown directly.

It suggests that culture has ancient origins, scientists write in Nature.

The study was carried out by a team at the University of St Andrews in the UK and the National Primate Research Center of Emory University in Atlanta, US.

They presented two different groups of chimps with a problem relevant to their wild cousins: how to retrieve an item of food stuck behind a blockage in a system of tubes.

One chimpanzee from each group was secretly taught a novel way to solve the problem. Ericka was taught how to use a stick to lift the blockage up so that the food fell out.

A chimpanzee watches her mother retrieve food (Drawing by Amy Whiten)

Another female chimp, Georgia, was shown how to poke at the blockage so that the ball of food rolled out of the back of the pipes.

Each chimp was then reunited with its group, and the scientists watched how they behaved.

They found that the chimps gathered around Ericka or Georgia and soon copied their behaviour. By the end of two months, the two different groups were still using their own way of getting at the food and two distinct cultural traditions had been established.

"This is the first time that any scientist has experimentally created two different traditions in any primate," Professor Andrew Whiten of the University of St Andrews told the BBC News website.

"Moreover, it is the first time anyone has ever done this with tool use in any animal."

Ancient origins

The research adds weight to decades of field studies on wild primates suggesting that they have rich cultural traditions unmatched in species other than our own.

Chimpanzees in West Africa, for example, use stones and pieces of wood to crack open nuts for food; but this has never been observed in chimps living in East Africa.

It suggests that the common ancestor of chimps and humans, living some four to six million years ago, probably also had a desire to conform - the hallmark of human culture.

"If both species have elements of culture, it is highly likely the ancient ancestor had too," said co-author Dr Victoria Horner, "so culture probably has a deep-rooted ancient origin."

The research is published in the online edition of the journal Nature.