Cat Ba Langur, Trachypithecus p. poliocephalus

Cat Ba Langur
Trachypithecus p. poliocephalus (Trouessart, 1911)
Vietnam
(2000, 2002, 2004)
Persisting on a single small island off the coast of Vietnam, the Cat Ba langurs have no escape from rampant poaching — they have lost 98% of their population in the past forty years.

This rare Asian colobine monkey is known only from Cat Ba, the largest of more than 3,000 islands located in northeastern Vietnam’s Halong Bay. The greatest part of the islands’ mountain range, like most of the smaller offshore islands, is covered by tropical moist limestone forest. Local livelihoods are built upon subsistence agriculture and more recently on a growing tourism industry, supplemented by hunting of wildlife and the collection of firewood, medicinal plants, honey and other forest products.
Poaching has been the major threat to the golden-headed langur and has resulted in a population decline from an estimated 2,500–2,800 langurs in the 1960s to a mere 53 individuals by 2000—a 98% decline in 40 years. Langurs were poached mainly for the preparation of traditional medicines. After the implementation of strict protection measures, for the first time in decades the population of the golden-headed langur increased to a minimum of 59 individuals at present. However, population fragmentation and low reproductive output also threaten them.

The remaining population is subdivided into seven isolated sub-populations. Some of these are all-female groups. Allwetter Zoo, Münster, and the Zoological Society for the Conservation of Species and Populations (ZGAP), München, have been carrying out a conservation program for the golden-headed langur on Cat Ba since November 2000. The aim is to provide for protection, reduce population fragmentation and increase public awareness, in collaboration with Vietnamese authorities with support from Conservation International, among other NGOs. Protection of the golden-headed langur has been designated a priority project of Fauna and Flora International’s newly-created Flagship Species Fund.

The closely related white-headed langur, T. poliocephalus leucocephalus Tan, 1957, is also Critically Endangered due to hunting and habitat destruction (expansion of sugarcane plantations). It inhabits seven isolated karst regions that cover 60–80 km² (in a total distribution of approximately 400 km²) in Guangxi Province, China. The karst formations are found in three separate and isolated protected areas: the Fusui and Chongzuo Rare and Precious Animal Reserves, and the Longgang National Nature Reserve. Estimated total population is about 600–800 animals.

In 1998, populations in Longgang and Fusui were found be in decline. A more recent survey (January, 2003) in Fusui, financed by the Asian Development Bank, however, has indicated some recovery since then. Numbers in Chongzuo have risen from less than 100 to more than 200 individuals since Professor Pan Wenshi of Peking University established a biological research program there in 1996. Chongzuo currently has the second largest population after Fusui and represents an example of how scientific presence can contribute significantly to wildlife conservation strategies. Dr. Chia Tan, a research fellow for the Zoological Society of San Diego, is working with the Peking University team to conduct ecological and behavioral studies and education campaigns at Chongzuo.

William R. Konstant, Roswitha Stenke, Tilo Nadler,
Roland Wirth, Zhaoyuan Li and Martina Raffel

References
Nadler, T. 1999. Goldschopflangur (Trachypithecus poliocephalus) im Endangered Primate Rescue Center, Vietnam und die Bestandssituation in seinem Verbreitungsgebiet. Zool. Garten N.F. 69: 241–245.
Nadler, T. and Ha Thang Long. 2000. The Cat Ba Langur: Past, Present and Future. The Definitive Report on Trachypithecus poliocephalus—the World’s Rarest Primate. Frankfurt Zoological Society, Hanoi. 104pp.
Nadler, T., Momberg, F., Nguyen Xuan Dang and Lormee, N. 2003. Vietnam Primate Conservation Status Review 2002. Part 2: Leaf Monkeys, pp. 55–67. Fauna and Flora International – Vietnam Program and Frankfurt Zoological Society, Hanoi.
Roos, C., Nadler, T., Zhang, Y. P. and Zischler, H. 2001. Molecular evolution and distribution of the superspecies Trachypithecus [francoisi]. Folia Primatologica 72: 181–182.
Stenke, R. and Chu Xuan Canh. 2004. The golden-headed langur (Trachypithecus poliocephalus poliocephalus) on Cat Ba Island—status, threat factors and recovery options. In: Conservation of Primates in Vietnam, T. Nadler, U. Streicher and Ha Thang Long (eds.), pp.72–77. Frankfurt Zoological Society, Hanoi.

Suggested citation:
Konstant, W. R., Stenke, R., Nadler, T., Wirth, R., Zhaoyuan Li and Raffel, M. 2005. Golden-headed Langur or Cat Ba Langur, Trachypithecus poliocephalus poliocephalus (Trouessart, 1911). In: Primates in Peril: The World's 25 Most Endangered Primates 2004-2006, R. A. Mittermeier, C. Valladares-Pádua, A. B. Rylands, A. A. Eudey, T. M. Butynski, J. U. Ganzhorn, R. Kormos, J. M. Aguiar and S. Walker (eds.), p.27-28. Report to IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS) and Conservation International (CI), Washington, DC.