The Orang Utan, genus Simia, has but one definable species, viz. S. satyrus. The supposed species of Owen, S. morio, cannot be satisfactorily defined. Plenty of other specific names have also been given to what is in all probability but a single species of large Anthropoid Ape inhabiting the islands of Borneo and Sumatra.
Fig. 279.—Skeleton of Orang. Simia satyrus. (After de Blainville.)
The name Orang-Utan, now applied exclusively to the subject of the present description, was formerly applied also to the Chimpanzee, and to that animal, moreover, under the latinised version of Homo sylvestris. The Orang is a large and heavy Ape with a particularly protuberant belly and a melancholy expression. The face of the old male is broadened by a kind of callous expansion of naked skin at the sides. The colour of the animal is a yellow brown, varying in the exact shade. The ears are particularly small and graceful in appearance, pressed closely to the sides of the head. The head is very brachycephalic. The arms are very long, and when the animal is in the erect posture they reach as far as the ankle. The hallux is very short and usually destitute of a nail. It is a curious fact that the head of the thigh bone is unattached by a ligament to the socket of the pelvis in which it articulates, a state of affairs which may give the limb greater freedom in movement, but does not add to its strength;
indeed, the Orang has been described as moving with laborious caution.
This Ape inhabits flat and forest-clad ground, and lives mainly in the trees. The male leads a solitary life except at the pairing season, but the female goes about with her family. On the ground the Orang walks with no great ease, and uses his arms as crutches to swing the body along. Even on trees the rate of progress is not rapid, and is accomplished with careful investigations as to the capabilities of the branches to bear his weight. The "Man of the Woods" has been stated to build a hut in trees. This is an exaggeration of the fact that it constructs a temporary nest.
Fig. 280.—A, Skull of a young Orang-Utan. Simia satyrus. (One-third natural size.) B, Skull of an adult Orang-Utan. (One-third natural size.) (From Wiedersheim's Structure of Man.)
One of these nests has lately been described elaborately by Dr. Moebius. It was found (by Dr. Selenka) on the fork of a tree at a height of 11 metres from the ground. Every night, as it appears, or every second night, the animal constructs a new nest for himself, abandoning the old one. So numerous, therefore, are these nests in localities frequented by Orangs, that a dozen can be readily found in a day. The particular nest which Dr. Moebius examined was 1.42 metres long, and at most .80 metre broad. It was built of about twenty-five branches, broken off and laid for