GIBBON

Gibbons (Hylobates). (genus Hylobates) any of about six species of small, manlike apes, family Hylobatidae, found in Indo-Malayan forests. Gibbons, unlike the great apes (chimpanzee, orangutan, gorilla), have small callosities on the buttocks and relatively longer arms. They have large canine teeth and their voices are characteristic in volume, musical quality, and carrying power. Gibbons are arboreal and progress from branch to branch with great agility by brachiation (swinging from the arms). On the ground, gibbons walk erect with the arms held aloft or behind. They are diurnal, live in small groups, and feed on shoots, fruit, and some insects, birds' eggs, and young birds. A single offspring is born after about seven months' gestation. Gibbons are long-haired, tailless apes about 4065 centimetres (1626 inches) in head and body length. They vary in colour, both within and among species, from tan or silvery to brown or black. In the concolour, or black, gibbon (Hylobates concolor) and the hoolock gibbon (H. hoolock), adult males are black and females are brown. The dark-handed gibbon (H. agilis) may be either tan or black and has white face markings. The white-handed gibbon, or Malayan lar (H. lar), is similar but also has white extremities. Kloss's gibbon (H. klossii), sometimes placed in the siamang genus, Symphalangus, is usually grayish. Gibbons are sometimes classified as the subfamily Hylobatinae, family Pongidae.