1911 Encyclopædia Britannica/Orang-Utan

ORANG-UTAN (“man of the woods”), the Malay name of the giant red man-like ape of Borneo and Sumatra, known to the Dyaks as the mias, and to most naturalists as Simia satyrus. The red, or brownish-red, colour of the long and coarse hair at once distinguishes the orang-utan from the African apes; a further point of distinction being the excessive length of the arms, which are of such proportions that the animal when in the upright posture (which it seldom voluntarily assumes) can rest on its bent knuckles. Very characteristic of the old males, which may stand as much as 51/2 ft. in height, is the lateral expansion of the cheeks, owing to a kind of warty growth, thus producing an extraordinarily broad and flattened type of face. Such an expansion is however by no means characteristic of all the males of the species, and is apparently a feature of racial value. Another peculiarity of the males is the presence of a huge throat-sac or pouch on the front of the throat and chest, which may extend even to the arm-pits; although present in females, it does not reach nearly the same dimensions in that sex. More than half-a-dozen separate races of orangutan are recognized in Borneo, where, however, they do not appear to be restricted to separate localities. In Sumatra the Deli and Langkat district is inhabited by S. satyrus deliensis and Abong by S. s. abongensis.

In Borneo the red ape inhabits the swampy forest-tract at the foot of the mountains. In confinement these apes (of which adult specimens have been exhibited in Calcutta) appear very slow and deliberate in their movements; but in their native forests they swing themselves from bough to bough and from tree to tree as fast as a man can walk on the ground beneath. They construct platforms of boughs in the trees, which are used as sleeping-places, and apparently occupied for several nights in succession. Jack-fruit or durian, the tough spiny hide of which is torn open with their strong fingers, forms the chief food of orang-utans, which also consume the luscious mangustin and other fruits. (See Primates.)