Orangutans are found in the tropical rain forests of only two islands in the world: Sumatra (in Indonesia) and Borneo (in Malaysia and Indonesia).
They are the largest arboreal (tree dwelling) animal in the world, reaching heights of four to five feet and weights of 125 to 235 pounds or more. Orangutans are reddish-brown in color and some males grow white or yellow beards. Also characteristic are their bare faces with round eyes and small ears; their long, shaggy hair; long arms; and curled fingers and feet.
Males are much larger than females and develop large pads on their cheeks called “flanges” and large throat pouches at the age 15 to 20. They spend most of their time in trees and subsist mainly on fruit, leaves, flowers, buds, bark and insects.
Distinctive habits and characteristics of Orangutans
- Adult males lead mostly solitary lives (except when consorting with females).
- Females associate with their infant and juvenile offspring and occasionally an adult sister or mother for short periods of time.
- Males communicate by the "long call" for territorial and courting purposes.
- Both sexes are arboreal, spending most of their time in trees, building nests at night, swinging through the trees, and eating in the trees.
- The lighter weight an orangutan is, the more active. As they grow older and heavier, they become slower and more cautious, testing each branch before putting their full weight on it.
- They rarely descend from treetops to ground; when they do, they usually walk on all fours (quadrupedal).
- Orangutans’ arms are stronger and longer than their legs (one-and-a-half times longer).
- Their reach from fingertip to fingertip can be as long as eight feet.
- They pucker up their lips to feel the texture of a piece of fruit or food before they bite into it. .
- While they are primarily herbivorous and love jungle fruits like durian, jackfruit, and lychee nuts, orangutans have been observed in the wild catching and eating a small animal called a slow loris.
- Females only give birth every seven to nine years, and their gestation period is about nine months (227 to 275 days).
- Infants nurse on their mothers for four to five years and stay in their mother’s nest for about seven to eight years.
- Females raise their infants alone.
- Orangutans can live 40 years in the wild and over 50 years in captivity.
Other Interesting Facts About Orangutans
There are three separate species of orangutan:
- Sumatran Orangutan (Pongo abelli)
- Bornean Orangutan (Pongo pygmaeus)
- Tapanuli Orangutan (Pongo tapanuliensis)
- Infant: Birth-to-four years (carried by mother)
- Juvenile: Four-to-eight years (still with mother)
- Early Adolescence: For females, eight-to-15 years and for males, eight-to-13 years
- Sub-adult: 13-to-18 years (males only)
- Adult: For females, 15+ years and for males, 18+ years
Critically Endangered Status
The current population of orangutans is less than 60,000 individuals (about 53,000 in Borneo and roughly 6,000 in Sumatra). They are gravely threatened to extinction due to habitat destruction (logging, farming, gold mining) and poaching for the exotic pet trade. When poached, mothers are killed, and if the baby survives the fall of the mother from the tree, the baby is taken by poachers.
One of the biggest threats today to orangutans is palm oil. Virgin forests where orangutans live and find all their food are cut down in order to plant the cash crop for palm oil. This oil is widely used in foods and consumers should be aware of ingredients in cookies, ice cream, and other foods and not buy products that use palm oil. More threatening now is the use of palm oil in biofuels. Nearly 5,000 orangutans a year have been killed or died over the past few years as palm oil plantations take up their habitat.