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Trachypithecus delacouri | Delacour's Langur


Good spot: Vân Long Nature Reserve, Ninh Bình Province, Việt Nam

Orange infant

© Catherine Workman

Van Long Nature Reserve




Taxonomy & Occurrence

Trachypithecus delacouri is a monotypic species (no subspecies). It is only found in north-central Vietnam (Hoa Binh, Ha Nam, Ninh Binh and Thanh Hoa Provinces).


IUCN Conservation Status

Critically Endangered


The Delacour's Langur, also known as "the langur who wears a pair of white shorts", has a characteristic white fur over the rump and outer thighs.


The Delacour Langur is another of the world's rarest primates, with perhaps only 250 individuals left in the wild [1]. The biggest viable population occurs in Van Long Nature Reserve (VLNR), which has approximately 150 individuals [1,2,3]. In August 2011, three captive-born individuals from the Endangered Primate Rescue Center were introduced in the VLNR for the first time ever, followed by another introduction of two individuals in November 2012 [4,5]. A second largest viable population was discovered through surveys by the Fauna and Flora International from 2016, where they found 13 groups of 73 Delacour's Langurs, with possibly up to 100 langurs in Kim Bang district, Ha Nam Province [1].


Even though they are leaf-eating primates, Delacour’s Langurs ate only a few plant species within their habitat, just 42 of 145 available species [6]. Sixteen plant species comprised more than 93% of their diet [6]!


Seeing this Species


Van Long Nature Reserve

Imagine rowing a wooden sampan boat in the pristine waters of the famous Van Long Nature Reserve, surrounded by rugged cliffs, a pair of binoculars hanging from around your neck and waiting patiently as nature unfolds before your eyes. Except you don't have to row the boat yourself.


After purchasing a ticket for a boat ride, a local (sometimes an older woman) would paddle you across the long and shallow lake separating the cliffs of the reserve from the nearest road, through enormous lilies and beneath towering limestone karst. The boat trips are something of a lottery; on one trip our boatwoman was quiet and helpful, and there was almost no-one else on the lake. On our second trip our boatwoman was loudly talkative and we were joined by another boat containing three locals who talked loudly and constantly with our boatwoman for the whole trip!


These langurs inhabit limestone habitat

© Matt and Maureen

Van Long Nature Reserve

The two hours after dawn and the two hours before sunset are by far the most likely times to see the langurs. We saw a group of five langurs, all adults, and watched them for about half an hour. They remained quite high on the cliffs, browsing occasionally, and might have been waiting for our boat to move off before coming closer to the water. Though the spotting can be difficult, the reserve is so spectacular it's worth a trip either way. 


Outside of the small reserve, however, is almost entirely surrounded by industry and lowland agriculture; quite a frightening sight given how critically endangered the langurs are. 


Van Long Nature Reserve is not far from Vietnam's oldest national park, Cuc Phuong National Park


Probability of success: ◆ ◆ ◆ ◇ ◇


Overlapping species:

  • Stump-tailed Macaque (Macaca arctoides)

  • Bengal Slow Loris (Nycticebus bengalensis

Other sites:

Cuc Phuong National Park, Ninh Binh Province, Vietnam

There are regular buses traveling between the park and Hanoi which take about 2.5 to 3 hours.


Overlapping species:

  • Stump-tailed Macaque (Macaca arctoides)

  • Assam Macaque (Macaca assamensis)

  • Rhesus Macaque (Macaca mulatta)

  • Northern White-cheeked Crested Gibbon (Nomascus leucogenys)

  • Bengal Slow Loris (Nycticebus bengalensis)

  • Pygmy Loris (Nycticebus pygmaeus

  • Indochinese Grey Langur (Trachypithecus crepusculus)


Local contacts

© Adam Hermans

Van Long Nature Reserve


[1] Knight T., 2019. Small steps and giant leaps - Signs of hope for Vietnam's primates.

[2] Ebenau A., Nadler T., Zinner D. & Roos C., 2011. Genetic population structure of the critically endangered Delacour’s langur (Trachypithecus delacouri) in Van Long Nature Reserve, Vietnam. Vietnamese Journal of Primatology 1 (issue 5): 1-15.

[3] Nadler T., 2010. Status of Vietnamese Primates – Complements and Revisions. In Nadler T., Rawson B.M. & Van Ngoc Thinh (eds): Conservation of Primates in Indochina. Frankfurt Zoological Society and Conservation International, Hanoi: 6-7.

[4] Nadler T., 2011. Reintroduction of Delacour's langur (Trachypithecus delacouri) into Van Long Nature Reserve, Ninh Binh Province, Vietnam. Report Frankfurt Zoological Society (Unpubl.).

[5] Nadler T., 2012. Reintroduction of the critically endangered Delacour’s langur (Trachypithecus delacouri) – a preliminary report. Vietnamese Journal of Primatology 2 (issue 1): 67-72.

[6] Workman C., 2010. Diet of the Delacour's langur (Trachypithecus delacouri) in Van Long Nature Reserve, Vietnam. American Journal of Primatology 72: 317-324.



Contributed by Matt and Maureen

Page Last Updated: 3 July 2022


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