Southern White-cheeked Gibbon

Common designation for a species of gibbon endemic to Laos and Vietnam, and with the scientific names Hylobates siki and Nomascus siki. It is one of two species of White-cheeked Gibbon, the other one being the Northern White-cheeked Gibbon, which today is found only in northern Laos and northern Vietnam, though it formerly also dwelled in Yunnan, in southern China. The Southern 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. Males are overall black with a prominent tuft and distinct white patches on the lower cheeks, around the edges of the mouth. Similar to the Northern White-cheeked Gibbon, it can be distinguished by its slightly shorten body hair and the fact that the patches reach only half way to the ears and to the edges of the lips, whereas in the northern species, the white cheek-patches run along the cheeks and reach to the upper borders of the ears, and do not touch the corners of the mouth (fig.). Females (fig.) are beige to orangey-buff, with a dark brown to blackish crown and a thin edging of white around the face. Juveniles are also light brown. Also known as Southern White-Cheeked Crested Gibbon. 回