The orangutan, or orangoutan, is a large manlike ape related to the gorilla and chimpanzee. Orangutans are very intelligent animals whose numbers are decreasing due to the destruction of their habitat by humans.

Where orangutans live

Orangutans are now only found in lowland swamp forests in Borneo and a small part of Sumatra. They used to live in the jungles of mainland Southeast Asia as well. The main reason that they are no longer as widespread seems to be that they have been hunted extensively by humans. Orangutans spend most of their time in trees.

Physical characteristics

Orangutans have a short, thick body, long arms, and short legs. Their coat is shaggy and red. Like their relatives the chimpanzees and gorillas, their arms are longer than their legs.

Adult male orangutans are about 4 ¹/₂ feet (1.4 centimeters) tall and weigh about 185 pounds (85 kilograms). Females usually weigh only about 90 pounds (40 kilograms). The male orangutan looks much different from the female. Not only is he bigger, he also has cheek flaps made up of fat and an air sac that forms a baglike swelling that hangs from the throat.

Behavior

Orangutans are active in the daytime. They use all four limbs to walk and climb along tree branches. Adult male orangutans sometimes must move along the ground to travel long distances, because smaller tree branches cannot support their weight. When walking, orangutans place the clenched fist—rather than the knuckles—on the ground to help them move.

Orangutans eat wild figs and other fruits picked from trees. They also eat leaves, bark, and even insects. Each night orangutans build a new sleeping platform out of branches in the trees.

Orangutans are very fairly silent. When they do make noises, they may grunt or smack the lips. The adult male has a “long call” made up of loud roars that he uses to communicate his location to other orangutans.

Reproduction

Unlike almost all other apes and monkeys, adult orangutans like to live alone. They come together only briefly before mating. A single young is born after about 275 days. The mother orangutan nurses her young and carries it at her breast or on her back. The young ape is usually on its own at the end of 3 years, by which time the mother has had another baby. Baby and young adult orangutans are more social than adults are. Orangutans may live longer than 30 years—at least in captivity.

Survival

The orangutan is considered an endangered animal. Hunting and the destruction of its habitat by humans have contributed to its declining numbers. The animal is protected by law in Indonesia and Malaysia.