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Trachypithecus crepusculus | Indochinese Grey Langur


Good spot: Phu Khieo Wildlife Sanctuary, Chaiyaphum Province, Thailand




Trachypithecus crepusculus is a monotypic species (no subspecies).



Southwestern China, Lao PDR, Myanmar, Thailand, northern Vietnam


IUCN Conservation Status

Endangered (under T. phayrei crepuscula)


Previously recognized as a subspecies of Phayre's Langur, the Indochinese Grey Langur is now a distinct species based on molecular data [1,2]



Seeing this Species


Phu Khieo Wildlife Sanctuary, Thailand

At least three habituated groups of grey langurs live here. Researchers note that the langurs "primarily inhabit the dry ever- green forest of Huai Mai Sot Yai [3]. However, they also used the edge between dry evergreen and dry dipterocarp forest, and they may (very rarely) cross small patches of dry dipterocarp forest on the ground." 


Probability of Success:  not bad if they're habituated...


Overlapping species: Sunda Slow Loris, Assamese Macaque, Northern Pig-tailed Macaque, Rhesus Macaque, Stump-tailed Macaque, White-handed Gibbon


Perhaps surprisingly Long-tailed Macaque does not occur here, even though the park is home to the other four of Thailand's five species of macaques [4]. 


Other sites:


Local contacts



[1] Roos C., 2004. Molecular evolution and systematics of Vietnamese primates. In: Nadler T., Streicher U. and Ha Thang Long (eds), Conservation of primates in Vietnam, Frankfurt Zoological Society, Vietnam Primate Conservation Programme, Endangered Primate Rescue Center, Cuc Phuong National Park, Hanoi, Hanoi, Vietnam.

[2] Roos C., Vu Ngoc Thanh, Walter L. and Nadler T., 2007. Molecular systematics of Indochinese primates. Vietnamese Journal of Primatology 1 (issue 1): 41-53.

[3] Gibson L. and Koenig A., 2012. Neighboring groups and habitat edges modulate range use in Phayre’s leaf monkeys (Trachypithecus phayrei crepusculus). Behavioral Ecology and Sociobiology 66: 633-643.

[4] Schülke O., Pesek D., Whitman B.J. and Ostner J., 2011. Ecology of Assamese macaques (Macaca assamensis) at Phu Khieo Wildlife Sanctuary, Thailand. Journal of Wildlife in Thailand 18: 1–15.



Page Last Updated: 28 September 2018


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