GIBBON, gibfbOn (Fr., of unknown origin). An East Indian anthropoid ape of the sub family Hylobatinte, the lower of the two divisions of the Simiidx, the other being the Simiinie, in cluding the gorillas, orangs, and chimpanzees. The gibbons are of a smaller size and more slender form than the simians, and their arms are so long as almost to reach the ground when the animal stands in an erect posture; there are also naked callosities on the buttocks. The head is well formed, while the lower jaw is remark able for the great de velopment of the chin.
The canine teeth are long. The gibbons are inhabitants of forests, their long arms en abling them to swing themselves from bough to bough, which they do to wonderful distances, and with extreme agil ity. They cannot move with ease or great ra pidity on the ground, yet when they make the attempt they walk more uprightly than any other ape, stretching out their arms on each side to balance themselves, with the hands hanging from the wrist. They never creep on all fours; and they sleep at night curled up in a ball. In captivity they display gentleness and a high degree of teachability, and learn to eat all sorts of cooked food, though their natural diet consists mainly of fruit and birds. They have va rious loud cries, expressive of different emotions.
There are two genera, Hylobates, with seven or eight species, and Siamanga. containing only one, the siamang (q.v.), which differs from the type in having the first and second digits of the hind foot united as far as the second joint. None of the gibbons is of large size. The common, or lar gibbon (Ifylobalcs /ar), black, with a bor der of gray hair around the face, is found in some parts of India, and in more eastern regions. The white-handed gibbon (Ilylobates albimana) black, the face bordered with gray, and the four hands white, is a native of Sumatra. The ac tive, or long-arined gibbon (Ifylobates agilis), found in Sumatra, is particularly remarkable for the power which it displays of flinging itself from one tree to another, clearing at once, it is said, a distance of forty feet. The wow-wow (Hylobates leueiseus) is a gibbon found in Java. The hoolock (Hylobates hooloek) is a native of the northeastern part of India and the neighbor ing parts of Assam. The fossil genus thropus (q.v.) had much resemblance to gibbons.
Consult: Hartman, Anthropoid Apes (London and New York, 1880) ; Haeckel, Aus Insulinde (Bonn, 1901). See APE; HOOLOCK ; SIAMANO; and Plate of ANTHROPOID APES.