Gray-Shanked Douc Langur
The gray-shanked douc langur is a leaf monkey of central Vietnam. The species may also occur in adjacent Cambodia. It is one of the world's most threatened primates. The IUCN Red List classes it as Critically Endangered.[1] Science first named it in 1997, from confiscated animals. Its gray shanks separate it from its red-shanked and black-shanked cousins.
A Critically Endangered douc of central Vietnam's evergreen forests.
- Common NamesGray-shanked Douc Langur, Gray-shanked Douc, Voọc chà vá chân xám
- Taxonomy Classification Year1997
- Monkey SizeHead and body 51 to 66 cm (20 to 26 in); tail 54 to 65 cm; weight 4.7 to 12.5 kg
- Skin Color(s)Gray-agouti body, white throat with an orange collar, black hands and feet, white tail; orange to yellow-brown face
- HabitatEvergreen lowland and montane forest, about 200 to 1,500 m
- DietHerbivorous (young leaves, fruit, seeds)
- Native CountriesVietnam
- Named in 1997 from animals confiscated by a rescue center.
- Young leaves make up about half of the yearly diet.
- Groups merge into bands of up to 88 animals.
- A 2016 survey in Kon Plong found about 500 more animals.
- Nearly 2,000 have been recorded across six Vietnamese provinces.
Gray-shanked Douc Langur Distribution
)Gray-shanked Douc Langur Guide:
Names and Taxonomy
Tilo Nadler described this monkey in 1997. He named it Pygathrix nemaeus cinereus, a subspecies of the red-shanked douc. The type locality is Pleiku in Gia Lai Province.[2] The epithet cinerea means ash-colored.
The animals behind the description had been seized from traders. The first known animal was confiscated from a restaurant in 1995.[3] Later authors raised the taxon to a full species. The Mammal Diversity Database now lists Pygathrix cinerea as valid.
The monkey is one of the Old World monkeys, family Cercopithecidae. Within it, the leaf-eating subfamily Colobinae holds the doucs. The site covers the wider group under types of langurs. Doucs are odd-nosed monkeys. Their closest relatives are the proboscis monkey and the pig-tailed langur. Vietnam's Tonkin snub-nosed monkey is a more distant cousin.[4]
Genetic work shows a close tie to the red-shanked douc langur. Nuclear DNA places the two as sister species. They split about 660,000 years ago. The black-shanked douc langur branched off earlier. Mitochondrial DNA tells a messier story. Some gray-shanked lineages group with red-shanked animals. The researchers considered past secondary gene flow the likeliest explanation.
The Vietnamese name is voọc chà vá chân xám.[5]
Appearance and Coat
The gray-shanked douc is a medium to large colobine. Males measure 55 to 66 cm from head to rump. Females measure 51 to 56 cm. The tail is about as long as the body. Males weigh 8 to 12.5 kg and females 4.7 to 11.7 kg.
The back, nape and crown are gray-agouti. That color runs down the arms. The chest, belly and throat are very pale whitish gray. Below the white throat sits a broad orange collar. A black line borders the collar and joins the black shoulders. The legs range from light gray-agouti to nearly black. Hands and feet are black. The tail is white with a thin tassel.
The bare face is orange to yellow-brown. The mouth and chin are white. Long white cheek whiskers frame the face. A small black band crosses the forehead. Males and females share the same coat. Males carry a pair of white tufts above the tail root. Females lack them. Male whiskers are also much longer.
Coat tone varies, from light gray to dark charcoal.[6]
Newborns look quite different. They have a pale gray-agouti back and a white belly. The head and outer legs carry a light chestnut tinge. That tinge fades to gray within about three months. The dark face turns yellow-orange over about three years.
The three doucs are told apart by shank color. The red-shanked douc has rust-colored lower legs. The black-shanked douc has fully black hind limbs and a blue-gray face.[7] The gray-shanked douc is the palest of the three. Its body tone places it among the gray monkeys.
Distribution and Range
The species lives in central Vietnam between about 16°N and 13°38′N. It spans Quang Nam, Quang Ngai, Binh Dinh, Kon Tum, Gia Lai. A 2025 note adds Phu Yen as a sixth province.[8] The 2025 note describes it as primarily Vietnamese, with adjacent Cambodia. The Handbook gives a small part of northeastern Cambodia. The Mammal Diversity Database marks Cambodia with a question mark. This page maps Vietnam only.
The range sits between the two other doucs. The red-shanked douc lives to the north. The black-shanked douc lives to the south. In northern Quang Nam the gray-shanked and red-shanked ranges overlap. Some hybridization occurs there.
Kon Ka Kinh National Park in Gia Lai holds the best-studied population. Other sites include Kon Cha Rang, Kon Plong and Song Thanh. Mom Ray, Ngoc Linh, A Yun Pa and Ba To hold more.
New populations keep turning up. In 2016 Fauna & Flora surveyed Kon Plong district in Kon Tum. The team found about 500 animals. That almost doubled the known global population.[9] In 2018 the group GreenViet found an isolated population near the coast. It lives in Tam My Tay forest in Quang Nam. It lies about 80 km east of the known range.[10] The animals survive in four forest islands among acacia plantations.[11]
In June 2024 surveyors found another group in Khe Lim Forest. It lies in Dai Loc district, Quang Nam. Seven animals lived in a 17 ha patch at mid elevation. Two more occupied sites followed in August 2024.
Habitat Preferences
It is one of the rainforest monkeys of Vietnam's central highlands. It uses evergreen lowland and montane moist forest. It can persist in some heavily degraded forest. Records run from about 200 m to about 1,500 m.
Diet and Feeding
The gray-shanked douc is one of the herbivorous monkeys. Leaves dominate the diet. Fruits and seeds add variety. Over a year, young leaves make up about half of feeding. Ripe fruit supplies about 22 percent. Unripe fruit adds 10 percent. Mature leaves contribute roughly 10 percent.
The menu shifts strongly with the seasons. Young leaves reach about 80 percent in the dry season. They fall to about 18 percent in the wet season. Fruit then climbs from under 10 percent to about 35 percent. Researchers at Kon Ka Kinh recorded 166 food plant species. They came from 40 plant families.
Digestion creates a high demand for water. A captive study found about 60 percent came from food. The remainder came from drinking, which increased with temperature. Wild doucs drink from ground water sources.
Behavior and Social Life
The species is diurnal and mostly arboreal. Animals come down to drink and lick minerals. The day begins between 05:00 and 06:00. It ends between 17:00 and 18:45.
Movement is mostly quadrupedal. Yet doucs often brachiate through the canopy. Captive gray-shanked doucs at Cuc Phuong arm-swing as often as red-shanked ones.[12]
Social life is layered. The basic unit is one male with several females. All-male groups, multi-male groups and lone males also occur. At Kon Ka Kinh one-male groups averaged about 15 animals. Up to six groups can merge into a band. Bands of up to 88 animals have been counted. This is a fission-fusion system. Males and females both leave their birth groups. The sex ratio is roughly one male to two females.
Group size sets the daily walk. Groups under ten animals move under 500 m a day. Groups over 20 move more than 2,000 m. A band of six one-male groups used 984 ha.
Resting fills about a third of the day. Males socialize more than females.
Reproduction and Lifespan
Births occur throughout the year. They peak between January and March. Females are receptive every 28 to 30 days. Gestation lasts 165 to 190 days. A single infant is born.
Longevity data for this species are thin. Captive red-shanked doucs have lived into their mid-twenties.
Breeding in captivity began at the Endangered Primate Rescue Center. The center sits in Cuc Phuong National Park. The center runs the species' captive breeding program.[13]
Population and Threats
The assessment inferred a decline of over 80 percent across three generations. A 2004 survey estimated 550 to 700 animals. The 2020 assessment estimated 1,450 to 1,700 animals globally. That figure allows for unsurveyed habitat.[14] The 2025 Oryx note reports nearly 2,000 animals already recorded. About half were outside protected areas. The true global population remains uncertain.
The 2020 assessment recognized 14 isolated subpopulations. Kon Ka Kinh National Park holds the largest protected group.
Hunting, trapping, habitat loss and fragmentation drive the decline. Doucs are shot for meat and for traditional medicine. A bone glue called cao drives much of the trade. Hunted doucs freeze in the canopy instead of fleeing. That makes them easy targets. Snares catch them when they come to the ground.
Forest loss compounds the problem. The IUCN assessment cites a loss of almost 10,000 ha yearly. Logging, farming and hydropower take their share. Roads fragment what remains.
Conservation Status
The species is Critically Endangered on the IUCN Red List. It is listed on CITES Appendix I. Vietnam protects all three doucs in Group IB. Decree 84/2021 amended the original 2019 list.[15]
The IUCN primate group named it among the 25 most endangered primates. It appeared on the 2012 to 2014 list.[16] The Handbook notes listings back to 2000.
Frankfurt Zoological Society runs a long-term study at Kon Ka Kinh. A corridor to Kon Chu Rang is a stated priority. At Tam My Tay, GreenViet guards the forest islands. It plants corridors and runs community ecotourism. The Khe Lim group now has its own survey project.
This site profiles many other types of monkeys. Readers can browse other monkeys starting with G.
Gray-shanked Douc Langur FAQ
The gray-shanked douc langur lives in central Vietnam. Records span Quang Nam, Quang Ngai, Binh Dinh and Kon Tum. Gia Lai and Phu Yen hold more.
Nearly 2,000 gray-shanked douc langurs had been recorded by 2025. The true total remains uncertain. The IUCN lists the species as Critically Endangered.
The gray-shanked douc langur eats mainly young leaves. Fruit and seeds make up the rest. Young leaves reach 80 percent of the diet in the dry season.
A male gray-shanked douc langur measures 55 to 66 cm. It weighs 8 to 12.5 kg. Females are smaller.
Hunting, trapping, habitat loss and fragmentation drive its decline. Doucs are taken for meat and traditional medicine.
The gray-shanked douc langur has gray lower legs and a paler body. The red-shanked douc has rust-colored lower legs and a thicker tail tassel.
Cite this page
BioExplorer. (2026, November 2). Gray-Shanked Douc Langur. https://www.bioexplorer.net/animals/mammals/monkeys/gray-shanked-douc-langur/
About the author
Wildlife Writer and Photographer, BioExplorer.net
Arjun is a science writer and wildlife photographer at BioExplorer.net. He turns new research on animals into clear, accurate reads for curious readers. His work covers animal behavior, ecology, and newly described species. He holds a Cornell Lab of Ornithology certificate in bird biology. He is pursuing an HBSc at the University of Toronto Mississauga.