The gibbon is the only anthropoid ape to walk on its hind limbs only, usually raising its arms for balance. They are quiet during the day but commonly howl at sunrise and sunset. Deciduous monsoon and evergreen rainforest of the islands and mainland of southeast Asia. Found in the subequatorial forests of India, Indochina, and the Malay Archipelago. The gibbon's most notable characteristic is its long arms, by which it swings from tree to tree with great agility, using its hands as hooks rather than grasping the limbs.
Gibbons are very territorial.
A pair maintains and defends a territory through a series of calls and vocalizations. They also use an elaborate system of calls to keep track of family members within the territory. When a juvenile becomes five or six years old, it is driven out of the family unit to establish its own territory. Card by Henson Robinson Zoo Education Department.