Orang-utans once lived in an area ranging from southern China to the foothills of the Himalayas and south to Java. Now they only survive on the islands of Borneo and Sumatra. Orang-utan populations on the two islands have been separate for more than a million years, and scientists now consider them as two distinct species: the Sumatran orang-utan and the Bornean orang-utan.
A century ago, there were around 230,000 orang-utans in Borneo and Sumatra. But, within the last decade alone, their numbers have fallen by between 30% and 50%, and now only around 7,500 survive on Sumatra and 55,000 on Borneo.
Orang-utans spend most of their time in the treetops. Their strong arms stretch out longer than their bodies (up to 2.1m across) and allow them to swing through the rainforest canopy or to hang from branches eating fruit and leaves.
Challenges and threats
The most serious threat to orang-utans is the destruction of their rainforest habitat. In the last 20 years an estimated 80% of suitable orang-utan habitat has disappeared, and only around 2% of what remains is legally protected.
The main causes of this habitat loss are commercial logging, clearance for agriculture, conversion to plantations, and associated infrastructure development. Not only is commercial logging often done illegally but it also results in the development of roads in previously inaccessible areas, which then provide easy access to poachers.
Despite legal protection in Sumatra and Borneo, orang-utans are often killed for their meat or caught for the pet trade. Between 1994 and 2003, a total of 559 orang-utans and gibbons were found on sale in 35 wildlife markets across the islands of Java and Bali.
WWF in action
WWF is working with Borneo’s governments to conserve the area known as the Heart of Borneo, through a network of protected areas and sustainably managed forests where hunting and illegal logging are prohibited. Without the maintenance of large blocks of inter-connected forest, there is a risk that orang-utans and hundreds of other species could become extinct. WWF is also restoring degraded forest areas, such as the recently designated Ulu Segama Forest Reserve, to conserve the orang-utan habitat.
WWF works with TRAFFIC (the wildlife trade monitoring network) to improve enforcement of wildlife laws preventing the trade in live animals and orang-utan products. We also work through advocacy campaigns to reduce the demand for keeping these animals as pets.