Tonkin Snub-nosed Monkey Rhinopithecus avunculus Dollman, 1912 Vietnam (2000, 2002, 2004, 2006)

The Tonkin snub-nosed monkey is one of four unusual, large Asian colobine monkeys of the genus Rhinopithecus, all of which possess a characteristic turned-up nose. The three other species are endemic to China, while the Tonkin snub-nosed monkey is found only in northern Vietnam. This species was discovered in 1911, collected on perhaps no more than two occasions over the course of the next 50 to 60 years, and subsequently presumed to be extinct by a number of primatologists until it was rediscovered in 1989. Historically the species occurs only east of the Red River between about 21°09'–23°N. Due to massive deforestation and intensive hunting in recent decades, its distribution has become dramatically restricted. Currently, there are only four known locations with recent evidence where Tonkin snub-nosed monkeys occur, and these are completely isolated. In 1992, a population was found in Na Hang District, Tuyen Quang Province. As a result of the discovery, a nature reserve was established in 1994. The nature reserve comprises two separate areas: the Ban Bung and Tat Ke sectors. A study in 1993 estimated a population of between 95 and 130 individuals in each sector, respectively, which was probably overestimated. A later study, in 2004–2005, found far lower densities, and estimated only 17–22 individuals in the Tat Ke sector. For the subpopulation of Na Hang Nature Reserve, the most serious threat was a hydropower and flood prevention dam project. Construction began in 2002. Some 10,000 workers moved into the area for dam construction, which has increased the demand for wildlife products and firewood. Conservation activities carried out by several organizations have been unsuccessful, and resulted in a reduction of this subpopulation. A population of about 70 individuals was estimated for Cham Chu Nature Reserve, also in Tuyen Quang Province. Based on local interviews during a survey reported in 1992 the population was believed to have dropped to only 20–40 individuals. A survey in 2006 provided no sightings and no reliable evidence of the survival of the population. Local reports indicate, however, a small group of 8-12 individuals still in the area. A population of about 60–90 Tonkin snub-nosed monkeys was discovered 2001 in Khau Ca, close to Du Gia Nature Reserve, Ha Giang Province. This is the only population which is not immediately threatened. There, public awareness and community participatory activities are being linked to increased protection efforts under the supervision of Fauna & Flora International (FFI). The total population of the Tonkin snub-nosed monkey is believed to be less than 150 individuals. Le Khac Quyet, Tilo Nadler & William R. Konstant

References Boonratana, R. and Le Xuan Canh. 1998. Conservation of Tonkin snub-nosed monkeys (Rhinopithecus [Presbyticus] avunculus) in Vietnam. In: The Natural History of the Doucs and Snub-nosed Monkeys, N. G. Jablonsky (ed.), pp.207–215. World Scientific Publishing, Singapore. Dong Thanh Hai, Do Quang Huy, Lu Quang Vinh, Nguyen Duc Manh, Nguyen Hai Ha, Ngo Duy Bach and Vu Duc Kham. 2006. A survey of distribution and population status of Tonkin snub-nosed monkey (Rhinopithecus avunculus) in Cham Chu Nature Reserve. Report, Forestry University of Vietnam, Department of Wildlife Manangement, Xuan Mai. Le Khac Quyet. 2004. Distribution and conservation of the Tonkin snub-nosed monkey (Rhinopithecus avunculus) in Du Gia Nature Reserve, Ha Giang Province, northeast Vietnam. In: Conservation of Primates in Vietnam, T. Nadler, U. Streicher and Ha Thang Long (eds.), pp.58–62. Frankfurt Zoological Society, Hanoi. Le Khac Quyet and S. P. Simmons. 2002. Results of surveys on Tonkin snub-nosed monkey (Rhinopithecus avunculus) in the Northeastern Vietnam. Report to Singapore Zoo and Fauna and Flora International, Hanoi. Nadler, T., F. Momberg, Nguyen Xuan Dang and N. Lormee. 2003. Vietnam Primate Conservation Status Review 2002. Part 2: Leaf Monkeys, pp.145–164. Fauna and Flora International and Frankfurt Zoological Society, Hanoi. Suggested citation: Le Khac Quyet, Nadler, T. and Konstant, W. R. 2007. Tonkin Snub-nosed Monkey, Rhinopithecus avunculus Dollman, 1912. In: Primates in Peril: The World’s 25 Most Endangered Primates 2006–2008, R. A. Mittermeier et al. (compilers), p.16. Unpublished report, IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS), and Conservation International (CI), Arlington, VA.