With their 6-foot-long arms and hand-like feet orangutans are ideally suited for an arboreal lifestyle. The apes spend most of their time in the trees. During the day, they forage for the 300 types of forest fruits, like durian, jackfruit, mangoes, and figs, which make up the bulk of their diet (the rest consists of other plant parts, plus honey, insects, eggs, birds, and lizards). At night, orangutans sleep in arboreal nests constructed from branches and foliage.
Orangutans are believed to be the most intelligent animals in the world other than humans. They are also the most solitary apes, and can be fiercely territorial, with the sexes usually coming together only to mate. Although females are fertile for about 30 years, they have offspring approximately every 8 years -- an interval that helps explains why the animals are so slow to recover from population disruption. Babies are nursed until they are about six years old; during nursing, the mother's hormone production is suppressed. Orangutan offspring have the longest period of childhood dependence of any animal in the world, and remain with their mother until after the arrival of her next baby; female offspring generally stay in the area where they were born, while males disperse, and establish home ranges that encompass those of several females.
In addition to their behavioral differences, the genders are highly dimorphic; females are much smaller than males, which have longer hair and prominent cheek pads.
Orangutans are considered critically endangered, largely because of hunting, loss of habitat, and capture for the illegal pet trade. This is particularly true in Sumatra, where only an estimated 7,000 to 7,500 animals remain in the wild.
Did you know? The name derives from the Malay and Indonesian phrase "orang hutan," which means "person of the forest."