Orangutans
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Introduction | Habitat | Behaviour | Development

Great Apes
The orangutans are, together with bonobos, chimpanzees and gorillas, members of the biological family Hominidae or great apes, to which also humans belong. These four great apes are considered to be the closest relatives to humans, showing resemblance in genetic characteristics (97% similar) as well as cognitive capacities and behaviour.


Unique apes
Orangutans are the most solitary and arboreal of the great apes. They spend a large amount of their time alone and in the trees. Orangutans are actually the largest tree living mammals in the world and the only red ape. Furthermore orangutans are the only great ape species living in South East Asia. While all the other great ape species are found in Africa, orangutans are only found in the tropical rainforests on the islands of Borneo and Sumatra, in the countries of Indonesia and Malaysia.


Genus Pongo
In the Ponginae subfamily of the great apes, only two species still exist, both belonging to the genus Pongo. These two orangutan species are both characterized by their long arms and reddish fur. They are distinguished as their deviation in habitat (two islands) suggests: Pongo abelii in Sumatra and the Pongo pygmaeus in Borneo.
The phenotypic differences between the two geographically separated species are apparent. The Sumatran orangutans are thinner and have paler red coats than their Bornean relatives. Hair and face are longer, with the face diamond shaped instead of square like as in the Bornean species. Adult males of both species have prominent cheekpads, called flanges. In the Sumatran orangutans these flanges are covered with fine, white hair and point more towards the front, whereas in the Bornean orangs the cheekpads are more horizontally stretched, markedly larger, and covered with short bristly hair. The throatpouches of the Bornean males are larger as well and are more pendulous.

Except for these phenotypic differences, the two species can also be distinguished genetically and behave differently as well. Sumatran orangutans for example are more social and hardly come to the ground, as opposed to their Bornean relatives which are more solitary and regularly come to the ground. Sumatran orangutans furthermore seem to have a longer life history.

What’s in the name
The name Pongo was used by Linnaeus in 1760, who laid the foundations for the modern system of taxonomy. The name Pongo comes from a 16th century account by Andrew Battell (an English sailor held prisoner by the Portuguese in Angola), in which the name Pongo was given to refer to an anthropoid monster, of which it is now believed, a gorilla was meant. Precise descriptions of species remained quite unclear until the end of the 18th century. It was in 1799, that Lacépède, a French naturalist, used the word Pongo to refer to the genus of which the orangutan belongs to.

Another name for orangutan, primarily used by local people is Maias or Mawas, which has its origins in the Malaysian language. It is however unclear to what these words refer to: only to orangutans, or all apes in general. The word orangutan also has its origins in the Malaysian language. Here the meaning is a lot more obvious and can be easily derived from the words "orang" and "hutan" which literally mean 'man of the forest'.