Color is variable. They all have a pronounced and complete white face ring, white hands and feet. Male song is simple with quaver-hoots, female song is longer, rising to climax, about 18 seconds long. Fur is extremely dense, providing protection from rain. Arms are very long , fingers are long and hook-like, and thumbs are thin and somewhat reduced.
Ischial callosities are present.
Middle and upper stories of deciduous monsoon and evergreen rain forest in southern Burma, Thailand, the Malay Peninsula, Sundaland to North Sumatra. Recently extirpated in Lancang county, China. May visit 16 or more widely spaced food trees in a day's foraging. Rest of diet consists of leaves, young plant shoots, flowers, birds' eggs, birds, insects, and spiders. Zoo diet is primate chow, fruits, vegetables and browse.