White-headed langur  (Trachypithecus poliocephalus)

The Cat Ba langur (T. p. policephalus) is endemic to Cat Ba Island, the largest of more than 3,000 islands in Halong Bay off the northeastern coast of Vietnam (4). There is no evidence that this subspecies has ever lived on the mainland (3). The white-headed black langur (T. p. leucocephalus) is found in south China where it occupies seven karst regions in Guangxi Province. These regions are spread across three isolated, protected areas known as the Fusui Rare and Precious Animal Reserve, the Chongzuo Rare and Precious Animal Reserve, and the Longgang National Nature Reserve (5).

In common with many members of the Trachypithecus genus, the white-headed langur is associated with the striking lush green hill forests on a limestone base that have become an icon of the southeast Asian landscape. They prefer altitudes of between 70 and 100 metres above sea level (4) and will regularly sleep within the complex cave systems of the karst landscape, particularly to shelter from poor weather (3).