Some of the great apes - chimps, gorillas, and orangutans - could be extinct in the wild within a human generation, a new assessment concludes. Human settlement, logging, mining and disease mean that orangutans in parts of Indonesia may lose half of their habitat within five years. There are now more than 20,000 humans on the planet for every chimpanzee.

The World Atlas of Great Apes and their Conservation is published by the UN's environment and biodiversity agencies. It brings together data from many sources in an attempt to assess comprehensively the prospects for the remaining great apes; the gorillas, chimpanzees and bonobos of Africa, and the orangutans of south-east Asia. The general conclusion is that the outlook is poor. "All of the great apes are listed as either endangered or critically endangered" co-author Lera Miles from the World Conservation Monitoring Centre near Cambridge told the BBC News website. "Critically endangered means that their numbers have decreased, or will decrease, by 80% within three generations." One critically endangered species is the Sumatran orangutan, of which around 7,300 remain in the wild. Most live in Aceh province at the northern tip of Sumatra, which saw armed conflict for decades between the Indonesian government and separatist rebels, and which suffered heavily during December's tsunami.