Gibbon in a tree.

Gibbons are apes in the family Hylobatidae (pronounced /ˌhaɪlɵˈbeɪtɨdiː/). The family is divided into four genera based on their diploid chromosome number: Hylobates, Hoolock , Nomascus, and Symphalangus. The extinct Bunopithecus sericus is a gibbon or gibbon-like ape which, until recently, was thought to be closely related to the Hoolock gibbons. Gibbons occur in tropical and subtropical rainforests from northeast India to Indonesia and north to southern China, including the islands of Sumatra, Borneo and Java.