Orangutan information extracted from the Orangutan Foundation International website with permission.

• Class: Mammalia
• Order: Primates
• Super family: Hominoidea
• Family: Pongidae
• Genus: Pongo
• Species: abelii (Sumatran) and pygmaeus (Bornean)
• Length: males - about 40 inches from top of head to rump; females - about 30 inches
• Weight: males - 110 to 300 pounds; females - 66 to 110 pounds
• Life Span: 60 years or more
• Gestation: about 8.5 months
• Number of Young at Birth: usually 1, very rarely 2 (in captivity)
• Size at Birth: 3.3 to 4.5 pounds
• Interbirth Interval: 8-9 years (in the wild)
• Age of Maturity: males - about 15 years; females - about 12 (in captivity)
• Conservation Status: Pongo pygmaeus (Bornean) is endangered; Pongo abelii (Sumatran) is critically endangered

Fun Facts!

• In Malay orang means "person" and utan is derived from hutan, which means "forest." Thus, orangutan literally means "person of the forest."
• Orangutans share nearly 97% of their genetic material with humans. Our close genetic relatedness with all the great apes make us sibling species.
• Orangutans’ arms stretch out longer than their bodies - over 7 ft. from fingertip to fingertip - and are used to employ a "hookgrip." When on the ground, they walk on all fours, using their palms or their fists.
• When male orangutans are about 15 years old, they develop large cheek pads, which female orangutans apparently find attractive.
• When males are fighting, they charge at each other and break branches. If that doesn’t scare one of them away, they grapple and bite each other.
• For the first few years of his/her life, a young orangutan holds tight to his/her mother’s body as she moves through the forest in search of fruit. Later, he/she will follow the mother as she moves through the trees.
• Like humans, orangutans have opposable thumbs. Their big toes are also opposable.
• Orangutans have tremendous strength, which enables them to brachiate (swing from branch to branch) and hang upside-down from branches for long periods of time to retrieve fruit and eat young leaves.

Species Information- extracted from the Orangutan Foundation UK website with permission

About a million years ago, orangutans lived throughout much of Asia, from Java in the south, right up into Laos and southern China. Today they are found only on the islands of Borneo and Sumatra.

Asia's only great ape, the orangutan has recently been re-classified as belonging to two distinct species, reflecting their geographical distribution: Pongo pygmaeus (on Borneo) and Pongo abelii (on Sumatra).

 

Orangutan Distribuition Map

The two species show slightly different physical characteristics. Sumatran orangutans have a narrower face and longer beard than the Bornean species. Bornean orangutans are slightly darker in colour and the males have wider cheek pads than their Sumatran relatives. Behavioural differences have also been observed between the two species; Sumatran orangutans are more frugivorous (fruit-eating) and there is evidence of tool use than in Bornean orangutans.

Under the IUCN (International Union for Conservation of Nature) Red List, the Sumatran orangutan is classified as critically endangered and the Bornean as endangered.

Bornean Male Orangutan

Sumatran Male Orangutan

Diet

Primarily frugivorous, orangutans have an important role as seed dispersers. They selectively choose ripe fruit whose seeds are adapted to withstand passage through the orangutans' gut. Once excreted, the seeds find themselves in their own little compost pile, which helps them to become established.

Over 400 food types have been documented as part of the orangutans' diet, and although it consists mainly of fruit, in times of scarcity orangutans will shift their eating habits to lower quality food, such as bark, leaves & termites, rather than travel to a different area. As well as acting as seed dispersers, orangutans help to open up the forest canopy. This allows light to reach the forest floor, which once again helps the forest regenerate.

Behavior

Orangutans are wholly dependent on trees for their existence. They are perfectly adapted to life in the forest - they sleep in nests, feed predominantly on fruit and travel with ease through the forest canopy, rarely descending to the forest floor.

Orangutans are almost unique amongst the primate species. All other apes and monkeys are social and gregarious, whilst the orangutan is semi solitary, the largest group being a mother and two offspring. Females are less solitary and may spend up to 25% of their time with other orangutans. In contrast, male orangutans will spend less than 9% of their time in association with other orangutans. Sumatran orangutans are more social and this social behaviour usually coincides with the simultaneous fruiting of the fig tree, which doesn't occur in Borneo .

Courtship lasts between 3-10 days and it is the female who, not wanting to share her food source, initiates the final separation. The male has no role in the raising of his offspring. It is thought that this solitary lifestyle evolved due to erratic fruiting, leading to competition for food. With a predominately frugivorous diet, containing relatively few calories for such a large body size, the orangutan needs to forage for 60% of the day, with the other 40% spent sleeping and resting.

Orangutans are the slowest breeding of all primates and, at almost eight years, have the longest inter-birth interval of any land-based mammal. The female orangutan reaches puberty at ten years and will normally have her first infant between the age of 12 and 15. Offspring are dependent on their mothers for at least five years and with a life expectancy of 45 years plus, females will normally have no more than three offspring. With these factors combined, the orangutan population, especially small fragmented populations, are at considerable risk. They don't have the capacity to recover from disasters that may strike a population. A slight rise in the adult female mortality rate by just 1-2% can drive a local population to extinction.

A larger map of the distribution of orangutans can be found here