London - Commercial hunting of mankind's closest animal relative, the bonobo or pygmy chimpanzee, may have brought the animals to the brink of extinction, the World Wildlife Fund (WWF) warned on Monday.

Urban Africans have developed a taste for "bushmeat" dishes such as bonobo stew. The bonobo is found only in the heart of the Congo basin. Much rarer than its cousin the chimpanzee, it is seen by many geologists as closest to humans on the evolutionary tree.

Scientists had earlier estimated the region's bonobo population at around 50 000 - but a new survey indicates that this is too optimistic. The educated guess is that only 10 000 still exist.

At this level, the species may not be able to sustain itself.

The survey, backed by the WWF, was conducted in Salonga National Park in the Democratic Republic of Congo. Researchers studied an area of 12 000 square kilometres, covering about a third of the park.

No sightings of live bonobos were made at all, and nests and dung were spotted in only a quarter of the region, at lower densities than had been encountered before. But the scientists found abundant evidence of poaching.

Callum Rankine, a senior international species officer for the WWF in Britain, said: "If these findings are mirrored across the park, we can kiss goodbye to our closest relative.

"Salonga National Park was created in 1970 specifically to safeguard the species and potentially represents the largest undisturbed and protected habitat for the bonobo.

"If things are this bad there, we can assume that across the Congo the species is in crisis."

The research was undertaken by the Congolese Institute for Nature Conservation (ICCN) and the Wildlife Conservation Society. Throughout the country's long-running civil war, it became almost impossible for the ICCN to protect national parks effectively.

Both local people and militia hunted bonobos during the war to eat.

The WWF has now launched a project to protect surviving bonobo populations in the northern sector of the park. As well as supplying park staff and researchers with training and equipment, it is supporting anti-poaching operations on foot and by boat.

"The war has had terrible consequences for the people and wildlife of the Congo basin," said Rankine. - Sapa-dpa