
Adult male, Vietnam
Photo by Le Khac Quyet
Tonkin Snub-nosed Monkey
(Rhinopithecus avunculus)
The Tonkin snub-nosed monkey is one of five species of snub-nosed monkeys (Rhinopithecus spp.), which include the gray snub-nosed monkey (R. brelichi), black snub-nosed monkey (R. bieti), golden snub-nosed monkey (R. roxellana), and the new species Burmese snub-nosed monkey (R. strykeri) recently discovered in 2010 [1]. The Tonkin snub-nosed monkey is critically endangered and is a global priority for conservation. Endemic to northern Vietnam, it is estimated that there are only approximately 200 individuals left in the wild [2]. It is also listed as one of the top 25 most endangered primates in the world [3].

A family group of Tonkin snub-nosed monkeys, Vietnam
Photo by Le Khac Quyet
Research to date
Of the five snub-nosed species, the Tonkin snub-nosed monkey is the only one for which we lack data on genetic variability [4]. It is also the species with the lowest population estimate: R. roxellana with approximately 15,000 individuals has the largest population, followed by R. bieti with a maximum of 2,000 individuals, R. brelichi with 750-800 individuals, and R. strykeri with 260-330 individuals [1].
Adult male and female
Video by Andie Ang
References
[1] Geissmann T., Ngwe Lwin, Saw Soe Aung, Thet Naing Aung, Zin Myo Aung, Tony Htin Hla, Grindley M. & Momberg F., 2011. A new species of snub-nosed monkey, genus Rhinopithecus Milne-Edwards, 1872 (Primates, Colobinae), from northern Kachin state, northeastern Myanmar. American Journal of Primatology 73: 96-107
[2] Le Khac Quyet, Dong Thanh Hai & Nadler T., 2009. Tonkin snub-nosed monkey (Rhinopithecus avunculus). In: Mittermeier et al. (eds.), Primates in Peril: The World’s 25 Most Endangered Primates 2008-2010, 58
[3] Mittermeier R.A., Schwitzer C., Rylands A.B., Taylor L.A., Chiozza F., Williamson E.A. & Wallis J. (eds.), 2012. Primates in Peril: The World’s 25 Most Endangered Primates 2012–2014. IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS), Conservation International (CI), and Bristol Conservation and Science Foundation, Bristol, UK., p25
[4] Yang M., Yang Y., Cui D., Fickenscher G., Zinner D., Roos C. & Brameier M., 2012. Population genetic structure of Guizhou snub-nosed monkeys (Rhinopithecus brelichi) as inferred from mitochondrial control region sequences, and comparison with R. roxellana and R. bieti. American Journal of Physical Anthropology 147, 1-10