The white-headed langur (''Trachypithecus leucocephalus'') is a

Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

species of

langur The Colobinae or leaf-eating monkeys are a subfamily of the Old World monkey family that includes 61 species in 11 genera, including the black-and-white colobus, the large-nosed proboscis monkey, and the gray langurs. Some classifications split ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Guangxi Guangxi,; officially the Guangxi Zhuang Autonomous Region, is an Autonomous regions of China, autonomous region of the China, People's Republic of China, located in South China and bordering Vietnam (Hà Giang Province, Hà Giang, Cao Bằn ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Taxonomy

It was formerly considered a subspecies of the Cat Ba langur (''T. poliocephalus''), which is now thought to be

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

. Its taxonomy was previously uncertain; it has been considered a partially albinistic population of the

François' langur François' langur (''Trachypithecus francoisi''), also known as Francois' leaf monkey, the Tonkin leaf monkey, or the white side-burned black langur is a species of Old World monkey and the type species of its species group. It is one of the leas ...

(''T. francoisi''), a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of Francois' langur, a valid species (''T. leucocephalus''), or a subspecies, ''T. poliocephalus leucocephalus''. However, the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

assessors and

American Society of Mammalogists The American Society of Mammalogists (ASM) was founded in 1919. Its primary purpose is to encourage the study of mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence ...

now recognize it as a distinct species based on a 2007 study which split both species. Populations of the white-headed langur in

Chongzuo Chongzuo (; ) is a prefecture-level city in the south of Guangxi, Guangxi Zhuang Autonomous Region near the Sino-Vietnamese border. It is home to one of China's largest Zhuang people, Zhuang populations. Geography and climate Chongzuo is locate ...

and

Fusui County Fusui County is a county (China), county in the southwest of Guangxi, China. It is the easternmost county-level division of the prefecture-level city of Chongzuo. Geography Fusui is located in southwestern Guangxi and in eastern Chongzuo City. I ...

display notable genetic divergence from the rest of the species, and it has thus been proposed they be treated as evolutionarily significant units.

Description

The white-headed langur is blackish in color with white crown, cheeks, and neck (in contrast to the similar ''T. poliocephalus'', which has a golden crown, cheeks, and neck).White-headed langur (''Trachypithecus poliocephalus'').
ARKive. Accessed 2008-07-15

Distribution

The white-headed langur has a very small range in the province of

in southernmost

, endemic to karst hills, where it is known from a few scattered populations. The

Zuo River The Zuo River (,) is a river of Guangxi, China. It begins from the confluence of the Bằng River and Kỳ Cùng River near Longzhou and joins the You River ("Right River") near Nanning to form the Yong River. These rivers form part of the P ...

separates its range from that of the François' langur farther north.

Status

The white-headed langur is listed as

on the

and is thought to have a population of no more than 600 individuals with roughly 250 mature individuals. None of the subpopulations has more than 25 individuals. It is mainly threatened by

poaching Poaching is the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the huntin ...

and to a lesser extent

habitat destruction Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

. In addition, François' langurs have been released within its range, and they have been known to hybridize with white-headed langurs, which may be genetically detrimental to it. The species has very low genetic diversity.

Habitat fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological proces ...

and anthropogenic land modification have negatively affected this, while other reasons may include its relatively short evolutionary history and restricted population size.

References

{{Taxonbar, from=Q28466511 white-headed langur Primates of East Asia Mammals of China Endemic fauna of China Critically endangered fauna of Asia white-headed langur Critically endangered fauna of China