A langur (family Cercopithecidae) that inhabits evergreen forests in the northwest of the Indochinese Peninsula (Bangladesh, China, India, Laos, Myanmar, Thailand, Vietnam). Diurnal and arboreal, it lives in the canopy 15–50 m above the ground. Body length is about 1.2 m with a tail reaching 80 cm; males weigh about 7.5 kg and females about 6 kg. Folivorous, feeding mainly on more than 80 species of leaves, and has a body adapted to digest fibrous leaves. Lives in groups of about 8–22 individuals led by one male; young males that have not reached sexual maturity may leave their natal group to form bachelor groups. Breeding occurs year-round, but births are concentrated in March–April; the gestation period is about seven months. Newborn infants have orange-colored fur. Populations are declining due to habitat loss and fragmentation from deforestation; listed as Endangered (IUCN Red List category I B).