Siamang

The Siamang (Hylobates syndactylus) is an arboreal black furred gibbon native to the forests of Malaysia and Sumatra. The largest of the lesser apes, the siamang can be twice the size of other gibbons, reaching 1 m in height, and weighing up to 23 kg. The Siamang and all the gibbons are classified in the genus Hylobates, some primatologists place the siamangs in their own genus, Symphalangus.

The Siamang is distinctive for two reasons. The first is the fact that two fingers on each hand are fused together (hence the name "syndactylus"). The second is the large "gular sac", a throat pouch which can be inflated to the size of the head, allowing siamangs to make loud resonating calls.

There are two subspecies of Siamangs: the Sumatran Siamang (H. s. syndactylus) and the Malaysian Siamang (H. s. continentis).

Siamangs can live up to 20 years in captivity.