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Sumatran orangutan

Scientific name: Pongo pygmaeus abelii

CLASS: Mammalia
ORDER: Primates
FAMILY: Hominidae

STATISTICS: Weight 77-220 lbs.; Height 2.4-4.6ft

Orangutans have long, sparse, coarse hair that covers most of their bodies. The hair of younger orangutans is bright orange in color and the skin is pink, while the hair of the adults is maroon or dark brown in color and the skin is almost black. Fine, white hair covers the male’s cheek pads. What appears to be a bored appearance is due to the lack of muscles in the face, thus making expressions non-existent. Adult males may have large cheek pads. Males are larger than females.

Northern Sumatra, a large Indonesian island.

Small area of the fragmented forest in the northern tip of the island. Orangutans are mostly found in the lowland and hilly tropical rainforest, which includes the peat swamp.

Orangutans are highly intelligent and adept at problem solving. They make tools to probe for food and use leaves to hold water or protect themselves from rain. An orangutan will make a nest of leaves and twigs 30 to 70 feet high in the trees. Each nest takes about five minutes to create and is generally abandoned after one use. The nest is often built with a roof structure to protect it from the rain. This is not normally seen in other great apes.

Orangutans have extremely long arms, which is a wonderful adaptation for living in the trees. An adult male’s arm span can be up to ten feet wide. In general, an orangutan’s arms are 1.5 times as long as its legs.

Orangutans are solitary animals and rarely leave the trees. Older males occasionally get too large to live in the trees and spend more time on the ground.

Breeding may occur all year long. A male will sometimes remain with a female for a number of days after mating. The pregnancy lasts 8.5 months. In the wild, an average female will have three or four infants in the 20 to 50 years of her reproductive life. Young stay with mom for eight years, become sexually mature at eight years, and breed before 15 years.

Sexual aggression is common among orangutans. Young males will try to force a female into copulation. However, mature females can generally fend off younger males, so they are rarely impregnated during these interactions.

Prey to humans and tigers
Predator to insects

Fruits, leaves, bark, bird eggs, insects and mineral rich soil

The Sumatran orangutan is listed as Critically Endangered with IUCN and is listed as CITES Appendix I. It’s estimated that only 6,500-7,500 remain. This is mostly due to human activities such as overpopulation, logging, and agriculture, which are destroying the orangutan forest environment. In fact, over the last 20 years, approximately 80 percent of the orangutans’ habitat has been destroyed. Much of their habitat has been converted to palm oil plantations. Palm oil is used in many products we use every day. Current estimates show that four times more land is in palm oil production than is reserved for orangutans.

The illegal pet trade and constant poaching are also endangering the orangutan population. If the uncontrolled destruction of their forest habitat continues, very soon there will be none of these shy and secretive apes left in the wild.


  • This orangutan is the rarer of the two species of orangutans, Sumatran and Bornean. The Sumatran orangutan, in comparison to the Bornean orangutan, is thinner and has a pale red coat. Its hair and face are longer. It also eats more fruit and less bark than the Bornean. It is thought to be slightly more social than the Bornean orangutan, and will occasionally gather in small groups near fig trees.
  • The orangutan’s nickname is “old man of the forest.”


  1. Nowak, Ronald M. Walker’s Mammals of the World, 5th Edition, Volume 1.
  2. Durrell Wildlife Conservation Trust. 2008.  July 2008.
  3. Singleton, I., Wich, S.A. & Griffiths, M. 2007. Pongo abelii. In: IUCN 2007. 2007 IUCN Red List of Threatened Species.  September 2008.
  4. UNEP-WCMC. UNEP-WCMC Species Database: CITES-Listed Species. September, 2008.

Published: March 2009

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