Several times removed they may be, but we share 97 per cent of our DNA with these apes. Indeed, the Indonesians don’t refer to them as monyet or monkey, they call them orang-utan - people of the forest - hiding there to avoid slavery, or having been banished for blasphemy. But while generations ago humans came down from the trees and walked off to start civilisation, orang-utans stayed high and mighty among the treetops.

Now civilisation is coming back to haunt them, closing in on the last few square miles of land they can still call their own. Orang-utans once spread from China to Java, but now they are confined to the small remaining pockets of moist forest on the Indonesian islands of Borneo and Sumatra.

The orang-utan is unique for many reasons. The only truly arboreal ape and the only one native to Asia, it builds up a sophisticated mental map of its habitat that tells it which trees will come into fruit next and where to go for food. Because of their foraging lifestyle, orang-utans spread out across the forest to ensure they have enough to eat and are solitary creatures, coming together only when food is plentiful or to mate.

The lone ape builds a nest every night out of branches and comes down to the ground only to travel long distances, in times of drought or to avoid fires.

Orang-utan babies have the longest dependency on their mother of any mammal - living with her for up to six years. During this time, they are taught how o navigate the jungle, open fruit and catch insects.

But some infant orang-utans never learn these things. Poachers hunt down and shoot nursing females, snatch the babies and sell them to illegal pet traders. Between three and five young orang-utans are thought to die for every one that reaches the black market.

Their evolutionary proximity to humans seems to be part of the attraction and, for them, the problem. Demand increased after a 1980s television programme in Taiwan featured one as a pet, and orang-utans have starred in films with Clint Eastwood and numerous advertisements. Several hundred are known to have been smuggled into Taiwan to be kept as pets. But they are highly susceptible to human diseases and will die or outgrow their domestic confines before reaching adulthood.

But the main threat to their existence - which fossils show goes back 35,000 years or more - comes from illegal logging and mining companies that have moved in, threatening conservationists who stand in their way. The loggers started huge forest fires on the islands in 1997-98 to clear land cheaply, destroying hundreds of these placid creatures and much of their habitat in the process.

While Indonesia’s population continues to grow - from 10 million at the turn of the 19th century to 200 million today - the true number of orang-utans left in the wild may be as low as 15,000. The species is critically endangered and in another five or 10 years may be extinct. Take another good look at your cousins. Then say goodbye. Because you might not see their like again.

HARVEY McGAVIN Weblinks education site: www.orangutan.com conservation issues: www.orangutan.org general: http:natzoo.si.eduzooviewexhibitsgreatapeorangs.htm