Genus and Species: Pongo
(Bornean) and Pongo abelii
The world's largest tree-dwelling animal, the orangutan
relies upon its intelligence and well-adapted body to survive
in the tropical rainforest.
These orangish-red-haired great apes have long arms and curved hands
and feet, which they put to good use when traversing the treetops.
Older orangutans usually move through the trees on all fours,
while young ones often brachiate, or swing hand over hand.
Males have longer hair than females and disc-like cheek pads.
Both sexes have throat pouches that make their calls resonate
through the forest. The males' pouches are more developed.
Orangutans crush tough foliage and hard-shelled nuts with
their strong teeth and jaws. Two species exist: P. pygmaeus of Borneo, and the Sumatran species, P. abelii. Outside
of their native ranges, they can be differentiated only through
chromosomal or DNA analysis.
Orangutans are Asia's largest primates, and males are larger than females. Males stand about four and a half feet tall and
weigh 130 to 200 pounds. Females stand about four feet tall and weigh 90 to 110 pounds. Zoo animals are
Once more widely distributed, orangutans now live only
in forests on the Southeast Asian islands of Sumatra and Borneo.
The Sumatran species is listed as critically endangered and the Bornean species is listed as endangered on the World
Conservation Union's Red List of Threatened
in tropical rainforests, including hill forests and swamp
feed primarily on forest fruits, including durians, jackfruits,
lychees, mangos, and figs. Leaves and shoots make up the remainder
of their diet, supplemented occasionally by small animals,
tree bark, and soils rich in minerals. Researchers have documented
more than 400 different foods eaten by wild orangutans.
establish home ranges that embrace those of several females.
Females reach maturity at around ten years of age and can
remain fertile for more than 30 years. Recent research suggests
that, on average, wild females give birth only every eight
years. Young orangutans may nurse until age six, and stay
close to their mothers until the next offspring comes along.
live about 35 years in the wild, and up to 60 in zoos.
Active during the
day, orangutans spend much of their lives high in the trees.
Solitary, they rarely encounter others of their kind unless
sharing a fruiting tree or mating. Each night, orangutans
bend branches into nest platforms that support the apes while
they sleep in the trees.
Orangutans move slowly through the forest, seeking fruiting
trees, which they may find by following the movements of hornbills
and other fruit-eaters. When heavily fruiting trees are found,
orangutans will spend many hours feeding.
widespread in Asian tropical forests, orangutans now live
only on Sumatra and Borneo, where forest loss is the greatest
threat to their existence. Naturally occurring forest fires,
and those set by farmers and large companies to clear the
way for plantations of oil palm, fast-growing pulpwood, and
other crops, devastate forests. The destruction spreads even
further during dry years. In 1997, an area the size of New
Jersey burned in Indonesia, and many of the fires occurred
in orangutan habitat. Large reserves and strictly enforced
wildlife protection laws are needed to keep orangutans safe
A Few Orangutan Neighbors:
proboscis monkey (Nasalis
larvatus): A large vegetarian that lives in forests near water
only on Borneo. Males are twice the size of females and have
Asian small-clawed otter
(Amblonyx cinerea): This small, social otter frequents streams
and swamp forests, where it eats crabs and other small animals.
(Aceros comatus): One of five species of large, long-billed
fruit-eating birds that share forests with orangutans on
Sumatra and Borneo.
By saving orangutan habitat, we protect these and many other
In Malay, "orang utan" means "person of the forest."
An adult orangutan's arms can be well over seven feet from fingertip to fingertip.