Delacour's Langur Trachypithecus delacouri (Osgood, 1932) Vietnam (2000, 2002, 2004) No more than three hundred Delacour's langurs survive in Vietnam, where they are ceaselessly poached — not for their meat, but to sell their bones and organs as ingredients for traditional medicines.

Delacour's langur is one of the most highly endangered of Southeast Asia's colobine monkeys. The species is endemic to Vietnam. During the decades following the discovery of the species in 1930 there was only scanty information on its existence and distribution. The first sightings of living Delacour's langurs were reported in 1987. The most important, and for some subpopulations the only, factor for the decline in numbers is poaching, which is not primarily for meat, but for bones, organs and tissues that are used in the preparation of traditional medicines. Nineteen isolated wild populations of Delacour's langur have been confirmed over 10 years of surveys and monitoring by the Frankfurt Zoological Society. The total population comprises 280 to 320 individuals. The recorded numbers of animals hunted over the 10 years totalled 320, an annual loss of more than 30 individuals, but the real number is undoubtedly higher. Sixty percent of all existing Delacour's langurs occur in isolated populations with less than twenty animals. The loss of these subpopulations, and consequently sixty percent of the whole population, is foreseeable without management, strict regulations and law enforcement. Four areas where Delacour's langurs are protected are: Cuc Phuong National Park, Pu Luong Nature Reserve, Hoa Lu Cultural and Historical Site, and the newly-established Van Long Nature Reserve, which is believed to harbor the largest remaining population of about 50 to 60 animals. This population is well protected due to patrols and close cooperation between the provincial forest protection authorities and Frankfurt Zoological Society. Monitoring surveys in 2003 and 2004 in Cuc Phuong National Park and in Pu Luong Nature Reserve show declines in numbers. Efforts to save this species are being led by Tilo Nadler, manager of the Vietnam Primate Conservation program of Frankfurt Zoological Society and director of the Endangered Primate Rescue Center at Cuc Phuong National Park, established in the 1990s primarily to safeguard the future of this and other endangered Vietnamese primates. William R. Konstant and Tilo Nadler

References Nadler, T. 1996. Report on the distribution and status of Delacour's langur (Trachypithecus delacouri). Asian Primates 6: 1-4. Nadler, T. 2004. Distribution and status of the Delacour's langur (Trachypithecus delacouri) and recommendations for its long-term conservation. In: Conservation of Primates in Vietnam, T. Nadler, U. Streicher and Ha Thang Long (eds.), pp.63-71. Frankfurt Zoological Society, Hanoi. Nadler, T., Momberg, F., Nguyen Xuan Dang and Lormee, N. 2003. Vietnam Primate Conservation Status Review 2002. Part 2: Leaf Monkeys, pp. 145-164. Fauna and Flora International and Frankfurt Zoological Society, Hanoi. Ratajszczak, R., Cox, R. and Ha Dinh Duc. 1990. A Preliminary Survey of Primates in North Vietnam. Report to World Wide Fund for Nature - WWF, Project 3869, Gland. Suggested citation: Konstant, W. R. and Nadler, T. 2005. Delacour's Langur, Trachypithecus delacouri (Osgood, 1932). 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. Report to IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS) and Conservation International (CI), Washington, DC.