|Scientific Name:||Pygathrix nemaeus|
|Species Authority:||(Linnaeus, 1771)|
|Taxonomic Notes:||This species is strongly suspected to hybridize in the wild with both P. cinerea and P. nigripes. However, knowledge of the zones of transition between the three taxa is limited, with little other anecdotal data to make assessments of its taxonomic significance (Timmins and Duckworth 1999; Nadler et al. 2004). Both these species have at times been considered conspecific with P. nemaeus.|
|Red List Category & Criteria:||Endangered A2cd+3cd+4cd ver 3.1|
|Assessor(s):||Ngoc Thanh, V., Lippold, L., Timmins, R.J. & Manh Ha, N.|
|Reviewer(s):||Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)|
Listed as Endangered as this species is believed to have undergone a decline of more than 50% in the last three generations (30–36 years, based on a generation length of 10–12 years), due to forest loss and hunting, and the decline is predicted to continue at the same rate or slightly higher in the next 30–36 years.
|Range Description:||This species occurs in east-central Lao PDR and northern and central Viet Nam and has recently been recorded in northern Cambodia. In Viet Nam, the southern limit is Kon Tum province and the northerly limit is Nghe An Province. This species is the only one of its genus found for certain in Lao PDR (Nadler et al. 2004), ranging from Nam Kading National Biodiversity Conservation Area in Bolkhamsay in the north south to the Xe Kong River in Attapeu Province. Doucs occur south of the Xe Kong, but pelage characteristics are ambiguous making identification problematic (Timmins and Duckworth 1999). The species was recently confirmed for northern Cambodia in Voensei district, Ratanakiri through genetic analysis, however, the extent of the species distribution in Cambodia is still to be determined. It should, however, be noted that these individuals show the same pelage characteristics as those described from southernmost Lao PDR (Timmins and Duckworth 1999; B. Rawson pers. comm.).|
Native:Cambodia; Lao People's Democratic Republic; Viet Nam
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population in Lao PDR is likely to be large, and is much more stable than that in Viet Nam, where after several decades of intense human pressure, populations have undergone significant declines. However, a recent survey conducted in the Son Tra Nature Reserve, revealed twelve groups of red-shanked douc langurs with at least 171 individuals at high densities (Lippold and Thanh 2008). In Lao PDR, the largest population occurs in the Nam Theun basin and surroundings, and encompasses several protected areas, representing the most important global population of the species (Timmins and Duckworth 1999).|
|Habitat and Ecology:||
This species occurs in undisturbed primary and secondary evergreen and semi-evergreen broadleaf forests (Lippold 1989); it is also associated with forests on limestone (karst). It is diurnal and arboreal (Timmins and Duckworth 1999), although the animals are sometimes seen on the ground. In Lao PDR, the species was recorded at up to 1,600 m in elevation (Timmins and Duckworth 1999).
They are mainly folivorous (Nadler et al. 2003), with an estimated 75% of their diet consisting of small tender leaves (Lippold 1989). They will also eat buds, fruit, seeds, and flowers (Nadler et al. 2003). Behavioral characteristics of this species make it easy to hunt (Nadler et al. 2003). Recent fieldwork has substantiated that groups vary in size, and that this variation may be related to environmental and human disturbance, especially hunting (Lippold 1989), although this may also be attributable to a fission-fusion social structure.
|Major Threat(s):||Hunting is currently the major threat to this species, most often for subsistence use and traditional “medicine”, as well as sometimes for the international pet trade, especially from Lao PDR to Viet Nam and Thailand (Timmins and Duckworth 1999; Nadler et al. 2004). Destruction of its natural habitat is also a threat to this species; a large portion in the central part of Viet Nam has suffered from post-war human demographic explosion and extensive logging for coffee, rubber, and cashew plantations (Nadler et al. 2004), as well as wood collecting. The translocation of some three million people from the north of Viet Nam to the central highlands is likely to exacerbate rates of habitat loss through the Vietnamese range of the species. In Lao PDR and Viet Nam, general infrastructure development, and specifically the construction of the Ho Chi Minh Highway, poses a major threat to the habitat of this species.|
This species is listed on CITES Appendix I, as well as under Appendix 1B of Decree 32 (2006) in Viet Nam. Both Viet Nam and Lao PDR have legislation regarding the hunting of this species, but this is not enforced (Lippold 1989; Timmins and Duckworth 1999).
P. nemaeus has been recorded from a number of protected areas throughout its range, including Nakai Nam Theun National Biodiversity Conservation Area, Hin Namno National Biodiversity Conservation Area, Phou Xang He National Biodiversity Conservation Area, Xe Bang Nouan National Biodiversity Conservation Area, Xe Sap National Biodiversity Conservation Area (Lao PDR); Bach Ma National Park, Phong Nha-Ke Bang National Park, Pu Mat National Park (Viet Nam). The species also occurs in Viet Nam in the proposed Khe Net Nature Reserve (M. Richardson pers. comm.) and Son Tra Nature Reserve (Lippold and Thanh 2008).
There is an ongoing captive-breeding program at the Endangered Primate Rescue Centre at Cuc Phuong National Park in Viet Nam.
Fooden, J. and Feiler, A. 1988. Pygathrix nemaeus in Hainan? New evidence, no resolution. International Journal of Primatology 9(3): 275 – 279.
Groves, C. P. 2001. Primate taxonomy. Smithsonian Institution Press, Washington, DC, USA.
IUCN. 2008. 2008 IUCN Red List of Threatened Species. Available at: http://www.iucnredlist.org. (Accessed: 5 October 2008).
Lippold, L. 1989. Reproduction and survivorship in douc langurs Pygathrix nemaeus in zoos. International Zoo Yearbook 28: 252–255.
Lippold, L. K. and Vu Ngoc Thanh. 2008. The Time is Now: Survival of the Douc Langurs of Son Tra, Vietnam. Primate Conservation 23: 1-5.
Nadler, T., Momberg, F., Nguyen Xuan Dang and Lormée, N. 2003. Vietnam Primate Conservation Status Review 2002. Part 2: Leaf Monkeys. Fauna and Flora International- Vietnam Program and Frankfurt Zoological Society, Hanoi, Vietnam.
Nadler, T., Streicher, U. and Ha Thang Long. 2004. Conservation of primates in Vietnam. Haki Publishing, Hanoi, Vietnam.
Timmins, R.J. and Duckworth, J.W. 1999. Status and conservation of Douc Langurs (Pygathrix nemaeus) in Laos. International Journal of Primatology 20(4): 469 – 489.
|Citation:||Ngoc Thanh, V., Lippold, L., Timmins, R.J. & Manh Ha, N. 2008. Pygathrix nemaeus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 03 September 2015.|
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