The Black-Shanked Douc Langur: A Rare Jewel of Southeast Asia’s Forest Canopy

What is the Black-Shanked Douc Langur?

The Black-Shanked Douc Langur (Pygathrix nigripes) is a striking and elusive species of Old World monkey belonging to the Colobinae subfamily—commonly referred to as leaf-eating monkeys. Recognized for its vibrant facial features and glossy black limbs, the Black-Shanked Douc is one of three douc langur species, the others being the red-shanked and grey-shanked doucs.

This primate is primarily arboreal (tree-dwelling) and diurnal (active during the day), living in the high canopy of tropical and subtropical forests. Its diet consists mainly of leaves, but it also consumes fruits, seeds, and flowers, playing a vital role in forest ecology.

Where Does the Black-Shanked Douc Langur Come From?

In terms of evolutionary origin and habitat, the Black-Shanked Douc Langur is endemic to Southeast Asia, specifically parts of Cambodia and Vietnam. It is a species that evolved in the tropical forests of the Indochina region, developing unique adaptations for life in the forest canopy.

Where is the Black-Shanked Douc Langur Found?

The Black-Shanked Douc Langur is found in:

• Eastern Cambodia, especially in Mondulkiri and Kratié Provinces
• Southern and southeastern Vietnam, notably in provinces like Đồng Nai, Lâm Đồng, and Bình Phước

Its habitat ranges include evergreen, semi-evergreen, and deciduous forests, typically in hilly or mountainous terrain. The species requires large tracts of forest with continuous canopy cover to thrive.

Where is the Black-Shanked Douc Langur Most Abundant?

The largest and most stable population of Black-Shanked Douc Langurs exists in eastern Cambodia, particularly within the Seima Biodiversity Conservation Area (SBCA) in Mondulkiri Province.

A comprehensive survey conducted in 2007 estimated that over 42,000 individuals resided in the SBCA alone—representing the largest known population of any douc langur species. By contrast, populations in Vietnam are significantly smaller and more fragmented due to habitat loss and hunting.

Who First Discovered the Black-Shanked Douc Langur?

The Black-Shanked Douc Langur was first described in scientific literature by Alphonse Milne-Edwards, a French zoologist, in 1871. He initially classified it under the genus Semnopithecus based on specimens collected near Saigon (now Ho Chi Minh City), Vietnam. It was later reassigned to the genus Pygathrix as part of taxonomic revisions based on its close relationship to other douc langurs.

What is the Significance of the Black-Shanked Douc Langur on Earth?

The Black-Shanked Douc Langur is ecologically, scientifically, and culturally significant:

• Ecological Role: As a folivore, it aids in seed dispersal and maintaining forest health. Its feeding habits help shape vegetation patterns in tropical forests.
• Biodiversity Indicator: Its presence signals healthy, undisturbed forest ecosystems, making it a key species for monitoring habitat integrity.
• Flagship Species: Due to its distinctive appearance and endangered status, it is a conservation flagship for Southeast Asian forest biodiversity.
• Cultural Importance: In local folklore and regional conservation efforts, doucs symbolize the beauty and fragility of tropical forests.

Who Named the Black-Shanked Douc Langur?

The species was scientifically named by Alphonse Milne-Edwards in 1871. The species name "nigripes" is derived from Latin, meaning "black-footed"—a direct reference to its distinctive black lower limbs. Over time, the species was moved to the genus Pygathrix, which was originally defined by Étienne Geoffroy Saint-Hilaire in the early 19th century for douc monkeys.

How Many Black-Shanked Douc Langurs Are There on Earth?

Population estimates are challenging due to the species’ elusive nature and the remoteness of its habitat. However:

• In Cambodia, the Seima Biodiversity Conservation Area alone is estimated to support more than 42,000 individuals (as of a 2007 survey).
• In Vietnam, fragmented populations persist, with the largest known groups containing between 500 to 700 individuals in specific protected areas such as Cát Tiên National Park and Bạch Mã National Park.

Taking these figures into account, the total global population is likely to range between 45,000 and 50,000 individuals, though accurate, updated surveys are needed to confirm these estimates.

Summary: Where is the Black-Shanked Douc Langur Most Abundant?

• The most abundant and stable population of the Black-Shanked Douc Langur is found in eastern Cambodia, particularly in the Seima Biodiversity Conservation Area, Mondulkiri Province.
• Vietnam hosts much smaller, more fragmented populations due to extensive habitat loss and hunting pressure.

Conclusion

The Black-Shanked Douc Langur is one of Southeast Asia’s most unique and endangered primates. While it enjoys relative abundance in parts of Cambodia, its future remains uncertain due to habitat destruction, hunting, and limited conservation enforcement—especially in Vietnam. Its continued survival will depend on sustained conservation efforts, habitat protection, and transboundary cooperation between Vietnam and Cambodia.

✅ Sources of Reference

1. IUCN Red List of Threatened Species
   ➤ Pygathrix nigripes assessment
   Link: https://www.iucnredlist.org/species/39856/17922526
2. New England Primate Conservancy (NEPC) – Douc Langur Species Profiles
   Link: https://neprimateconservancy.org/douc-langurs/
3. WWF Cambodia – Wildlife at Risk: Black-Shanked Douc Langur
   Link: https://www.wwf.org.kh/our_work/wildlife_at_risk_in_cambodia/mammals/black_shanked_douc/
4. ScienceDaily – “World’s Largest Population of Globally Endangered Primate Discovered in Cambodia”
   Article on Seima Biodiversity Conservation Area
   Link: https://www.sciencedaily.com/releases/2008/08/080828120326.htm
5. Ecology Asia – Black-Shanked Douc Langur (Pygathrix nigripes)
   Link: https://www.ecologyasia.com/verts/mammals/black-shanked-douc.htm
6. Mammal Diversity Database (MDD) – American Society of Mammalogists
   Entry for Pygathrix nigripes
   Link: https://www.mammaldiversity.org/taxa.html
7. Fauna & Flora International (FFI) – Cambodia and Vietnam primate conservation efforts
   Link: https://www.fauna-flora.org
8. Vietnam Primate Conservation Program (VPCP)
   Regional studies on douc langurs in Vietnam
   Link: https://www.primate-sg.org/vietnam/