Northern White-cheeked Gibbon

Common designation for a species of gibbon found only in northern Laos and northern Vietnam, and formerly also in Yunnan, in southern China. It has the scientific names Hylobates leucogenys and Nomascus leucogenys and is one of two species of White-cheeked Gibbon, the other one being the Southern White-cheeked Gibbon, which is endemic to Laos and Vietnam. The Northern White-cheeked Gibbon is also closely related to the Golden-, Yellow- or Buff-cheeked Gibbon (Nomascus gabriellae), a species native to Indochina, and to the Black Crested Gibbon (Hylobates concolor), found in southern China, Laos, and northern Vietnam. Whereas males are overall black with distinct white patches on the cheeks and a prominent tuft (fig.), females are reddish-brown, with a dark brown to blackish crown (fig.). Similar to the Southern White-cheeked Gibbon, it can be distinguished by its slightly longer body hair and the shape of the white cheek-patches in males, which reach to the upper borders of the ears and do not touch the corners of the mouth, whereas in the southern species, the patches reach only half way to the ears and to the edges of the lips (fig.). 回