orang-utan

The orang-utan is the only surviving species of great ape outside Africa. It split off from its close relatives, the gorillas and chimpanzees, perhaps 15 million years ago. Its long, powerful arms enable it to swing quickly through the tree branches; its legs are comparatively short and weak.

Large ape found only in Borneo and Sumatra. Up to 1.65 m/5.5 ft in height, it is covered with long, red-brown hair and lives a largely solitary life in the trees, feeding mainly on fruit. Now an endangered species, it is officially protected because its habitat is being systematically destroyed by deforestation. In 1998 there were fewer than 27,000 orang-utans in the wild, with an estimated 5,000-7,000 in Sumatra, 3,000-5,000 in Sabah (northeast Borneo), and 12,000-15,000 in Kalimantan (Indonesia). (Species Pongo pygmaeus.)

There are two subspecies: P. p. pygmaeus found in Borneo, and the smaller P. p. abelli on the island of Sumatra. Their rate of reproduction is very slow, with an eight-year gap between births. Orang-utans are slow-moving and have been hunted for food, as well as by animal collectors. The name means ‘man of the forest’.

An orang-utan population in the Suaq Balimb rainforest in Sumatra uses tools. This population is more sociable than most orang-utans and they use twigs to extract honey and insects from holes in trees and seeds from fruits protected by stinging hairs, much as chimpanzees use twigs for termite ‘fishing’. Like all orang-utans, this unique population is under threat from logging.