Gibbons are apes in the family Hylobatidae. The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast India to southern China and Indonesia (including the islands of Sumatra, Borneo and Java).
Also called the lesser apes or small apes, gibbons differ from great apes (chimpanzees, bonobos, gorillas, orangutans, and humans) in being smaller, exhibiting low sexual dimorphism, and not making nests. Like all apes, gibbons are tailless. Unlike most of the great apes, gibbons frequently form long-term pair bonds. Their primary mode of locomotion, brachiation, involves swinging from branch to branch for distances up to 15 m (50 ft), at speeds as high as 55 km/h (34 mph). They can also make leaps up to 8 m (26 ft), and walk bipedally with their arms raised for balance. They are the fastest of all tree-dwelling, nonflying mammals.
Depending on the species and sex, gibbons' fur coloration varies from dark- to light-brown shades, and any shade between black and white, though a completely "white" gibbon is rare.