Orangutan Facts

by Liz Osborn CurrentResults.com

Listed here are over 20 interesting facts about orangutans. You can learn the basics about where these jungle primates live and what they eat.

Plus you'll find some surprising information about how smart orangutans are, and the ways they communicate and socialize with each other.

Orangutan Intelligence

Orangutans are among the few animal species with a sense of self. They recognize themselves in mirrors.
Orangutans in the wild use tools made from branches and leaves to scratch, scrape, wipe, sponge, swat, fan, hook, probe, scoop, pry, chisel, hammer, cover, cushion and amplify. Orangutans are innovators. They'll often take a tool and give it a new use. Or they'll solve a problem in a new way. The inventiveness of orangutans has in fact often surprised scientists who've spent hours observing the animals.
An animal keeper who whistled while working at the Smithsonian National Zoological Park in Washington, D.C inspired Bonnie, a female orangutan living at the zoo. She taught herself how to whistle tunes, in the same manner that humans do, with variations in the duration and number of notes. Scientists had never before heard an ape or monkey teach themselves to imitate a human sound. Bonnie has caused researchers to rethink their theories about orangutans' ability to learn.
Highly intelligent, orangutans perform as well as chimpanzees in problem-solving tests.
At zoos, orangutans apply their smarts to devise elaborate escapes. One clever female at the Adelaide Zoo in Australia disabled the electric fence around her enclosure by jamming a stick into the wires. Once through that barrier, she piled up debris that she then used as a ladder to climb a concrete wall.

Two species of orangutans exist in southeast Asia. The Sumatran Orangutan (Pongo abelii) lives on the northern part of Indonesia's Sumatra Island. The Bornean Orangutan (Pongo pygmaeus) has three subspecies, all found on Borneo in Malaysia and Indonesia.
Sumatran orangutans are in fact the most endangered of any great ape species. Perhaps 6,500 remain and their numbers are dropping. Populations of Bornean orangutans, which number about 50,000, are also endangered and in decline.
Among the main threats to orangutan survival is loss of their rainforest habitat. Logging and converting forests to crops, particularly oil palms, have recently destroyed orangutan habitat at a rapid rate.

Sumatran Orangutan (Pongo abelii). Photo: Anup Shah

Wild orangutans live almost entirely in trees. In fact, Sumatran females never travel on the ground. Orangutans are the largest tree-living mammal on earth.
Although tree dwellers by nature who avoid ponds and streams, orangutans that live semi-wild on Kaja Island in Kalimantan's Rungan River enjoy playing in water and some even swim.
Orangutans inhabit mountainous regions, but keep to lowland forests, below 1,000 metres (3,300 feet) elevation. A female's home range extends up to 15 square kilometers (6 square miles), while male territories are several times larger.
As gymnasts of the rainforest, orangutans use many different maneuvers to move around. To get across a wide gap between trees, for instance, an orangutan climbs high up the trunk of a slim tree and makes the tree sway. As the swaying becomes more vigorous, the tree takes the orangutan farther across the gap. Once the tree bends far enough over the gap, the great ape crosses easily to the next tree.

Wild orangutans eat over 500 species of plants. Fruit forms most of their diet, but they also eat leaves, bark, flowers and insects.
Orangutans make tools to help them get at food. They'll take a live branch and strip off leaves, twigs and bark to fashion a probe to scoop honey from bees' nests, pull ants and termites out of tree holes, or extract seeds from husks equipped with stinging hairs.

Adult orangutans mostly live alone. Females occasionally socialize with neighboring female orangutans.
Females raise one youngster at a time. They first give birth at around 15 years of age and a new sibling arrives every 6 to 9 years
During the first three years, young orangutans rely heavily on their mother to find food and move through the jungle. They continue to learn from mom about food foraging and share her nest until they're 6 or 7 years old.
Two different forms of mature adult males exist. Flanged males grow to twice the size of females and develop cheek flanges and a throat sack that's used for making calls which can be heard over long distances. Unflanged males do not have these characteristics and are the size of adult females, yet still father offspring. An unflanged male can turn into a flanged male at any time, even when over 30 years old.
Orangutans typically live to over 50 years of age.

Orangutans invent and learn from each other. So each group of wild orangutans develops unique ways of doing things, forming a community culture.
The orangutan vocabulary contains at least 32 different sounds. Some sounds are dialects, made only by members of certain communities.
Orangutans in a few wild groups hold a handful of leaves in front of their lips while creating a "kiss squeak" alarm call, to make their call sound deeper. The lower-frequency call tricks intruders into believing the orangutan is bigger than it acutally is. Scientists have never before come across an animal, besides humans perhaps, who exaggerates its size by using a tool to modify its call.
Every day, each orangutan builds a nest for sleeping in a tree. But nest architecture varies among orangutan groups. Orangutans in some places build a canopy over their nest to shield themselves from the sun. In one community, orangutans line their nests with leaves from a plant that repels insects.