Germain’s Langur
Germain's langur is a pale gray leaf monkey of mainland Southeast Asia. Its scientific name is Trachypithecus germaini.[1] It is also called the Indochinese silvered langur. It lives west of the Mekong River, from Thailand to southern Vietnam. It is one of the Old World monkeys. The IUCN lists it as Endangered.[2]
This Endangered langur lives in lowland forests west of the Mekong River.
- Common NamesGermain's langur, Indochinese silvered langur, Indochinese lutung, Germain's silver langur
- Taxonomy Classification Year1876
- Monkey SizeAbout 55 cm (22 in) head and body, tail 72 to 84 cm (28 to 33 in)
- Skin Color(s)Pale gray coat, slaty-black face, black hands and feet
- HabitatLowland evergreen, deciduous, mangrove, swamp and karst forest, reported to 600 m
- DietMostly young leaves, plus fruit, mature leaves and flowers
- Native CountriesCambodia, Laos, Thailand, Vietnam, Myanmar (disputed)
- Its pale gray coat contrasts with a slaty-black face.
- Long creamy-yellow hairs frame its face like a halo.
- Its infants are born with a golden-orange coat.
- Young leaves make up most of its diet.
- Hunting and habitat loss are driving its decline.
Germain's Langur Distribution
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Name and Classification
French zoologist Alphonse Milne-Edwards described this langur in 1876. He named it Semnopithecus germani. Its type locality is given as Cochin China and Cambodia. Four syntypes are kept in the Paris natural history museum.
For decades it was treated as part of the silvered langur. That species, Trachypithecus cristatus, lives on Sumatra and Borneo.
Later work gave mainland populations their own species. A 2008 study then split that species in two.[3] Researchers compared mitochondrial DNA from 115 silvered langurs. They found five distinct lineages and ranked each as a species. One was Germain's langur. Another was the Annamese silvered langur, which lives east of the Mekong.
A 2020 mitogenome study dated these splits.[4] The mainland pair split from Sundaland species about 1.25 million years ago. The two mainland species parted about 0.87 million years ago.
Together they form the cristatus species group. The Selangor silvered langur belongs to it. So do the East Javan langur and the West Javan langur. Browse more types of langurs on our hub.
Four Thai langurs studied in 2015 had 44 chromosomes.[5]
Physical Description
Germain's langur has pale grayish fur.[6] Its underside, throat and shanks are lighter still. That coat makes it one of the gray monkeys of Asia.
Its forearms are dark gray. Its hands and feet are black. The tail is black above and paler below. Those dark parts also place it among our black monkeys.
The face is slaty black. Long, creamy-yellow hairs surround it. They form a distinctive halo around the face.
Adult females have a whitish pubic patch.
Infants look completely different. They are born with a golden-orange coat. Their faces, hands and feet are white.
Compared with the silvered langur, it is larger and paler. It also has a longer tail.
Size and Weight
Few published measurements exist for this species. The Handbook of the Mammals of the World gives its size. Head and body length is about 55 cm (22 in). Its tail measures 72 to 84 cm (28 to 33 in). Adults weigh 6.5 to 7 kg (14 to 15 lb).
The handbook does not split these figures by sex. It gives no sample size either.
The tail is clearly longer than the head and body.
Similar Species Compared
Genetic studies show the Annamese silvered langur is its closest relative. The two look much alike.[7] The Annamese has a gray face, often with white eye rings. Its black forehead contrasts with its pale body. Germain's langur has a slaty-black face and a creamy-yellow halo.
The Mekong River probably divides the two species.[8] In Cambodia's Keo Seima Wildlife Sanctuary, a large population looks intermediate. It lives east of the Mekong.
The silvered langur lives far to the south, on Sumatra and Borneo.[9] It has a high, pointed crest. Its gray coat varies from silvery to almost greenish. It lives mainly in riverside, mangrove and swamp forest.[10]
| Trait | Germain's langur | Annamese silvered langur | Silvered langur |
|---|---|---|---|
| Scientific name | Trachypithecus germaini | Trachypithecus margarita | Trachypithecus cristatus |
| Range | West of the Mekong, Thailand to southern Vietnam | East of the Mekong, Cambodia, Laos and Vietnam | Sumatra, Borneo and nearby islands |
| Habitat | Lowland, mangrove, swamp and karst forest, reported to 600 m | Lowland evergreen and deciduous forest, 100 to 650 m | Riparian, mangrove and swamp forest, to 300 m |
| Coat and key marks | Pale gray, slaty-black face, creamy-yellow halo | Pale gray, gray face, black forehead, often white eye rings | Variable gray, high pointed crest, slaty-black face |
| Head and body | About 55 cm, sex not given | Not known | Males 50 to 58 cm |
| Tail | 72 to 84 cm, sex not given | Not known | Males 67 to 75 cm |
| Weight | 6.5 to 7 kg, sex not given | Not known | Males about 6.6 kg |
| Diet | Mostly leaves, 67.5% in one karst study | Mostly leaves, 61.5% in one study | Mostly leaves, 60 to 80% |
| Group size | 7 to more than 50 | Not known | Not known |
| IUCN status | Endangered (assessed 2015) | Endangered (assessed 2015) | Vulnerable (assessed 2015) |
Range and Distribution
Germain's langur lives west of the Mekong River. Its exact range limits are still unclear, the IUCN notes.
In southern Laos, it reaches north to about 15.4°N. It is widespread in Cambodia west of the Mekong. It lives in the Cardamom Mountains and the Tonle Sap flooded forests. It also ranges across the Northern Plains near Laos.
In Thailand, it extends west to Kanchanaburi Province. It occurs in Huai Kha Khaeng Wildlife Sanctuary and on Ko Chang. That makes it one of the Thailand monkeys.
In Vietnam, it survives only in the Mekong Delta.[11] A 2017 survey confirmed it at six of seven sites. They lie in An Giang, Ca Mau and Kien Giang provinces. Its southernmost record, at 8°50′N, is in Ca Mau.
Myanmar is disputed. The IUCN and MDD list it there. The 2020 mitogenome study disagrees. It says Myanmar records rest on a misassigned old name.
Habitat Needs
This langur uses a wide range of forest types. In Cambodia, it lives in evergreen and semi-evergreen patches. These patches sit within drier deciduous forest. It also uses riverside strips, gallery forest and flooded forest.
In Vietnam, its habitats are even more varied. They include mangrove, Melaleuca swamp forest and limestone karst forest. On Phu Quoc Island, it lives in evergreen forest. Those moist forests make it one of the rainforest monkeys of Indochina.
It is mainly a lowland species. No Cambodian record lies above 450 m (1,480 ft). Tran Van Bang reports it to 600 m on Phu Quoc.
Diet and Feeding
A two-year study watched langurs on Chua Hang karst, Vietnam.[12] It logged 17,040 feeding bouts from 2014 to 2016. Feeding took up 45% of their time.
Young leaves made up 58% of the plant diet. Fruit made up 22.7%, and mature leaves 9.5%. Flowers, buds, leaf stalks and other items made up the rest. That leafy diet puts it among the herbivorous monkeys.
The langurs fed on 58 plant species. Phyllanthus reticulatus was eaten most, at 13.9% of feeding time. Leaves of eight species were eaten all year, including three figs.
They chose leaves with less tannin and lignin. Those leaves held more sugar than the plants they ignored. The handbook notes they also eat soil now and then.
Behavior and Groups
Germain's langur is active by day and lives in the trees.
Its groups range from seven to more than 50 animals. An older handbook gives 9 to 30, averaging 17. Each holds several adult males and several females. Groups also split up and rejoin, a fission-fusion pattern.
Breeding is not seasonal. Hoang Minh Duc has seen orange infants most from November to May.
Population and Status
No global population estimate exists. Most counts are local estimates, not censuses.
Keo Seima Wildlife Sanctuary holds a large intermediate population. It lies east of the Mekong. Both IUCN assessments include this intermediate population. Monitoring there has run since 2010. A 2020 estimate put that population at 1,487 animals. Its 95% confidence interval was 588 to 3,758. That population appears stable. Cambodia's Northern Plains may be a stronghold.
Vietnam's total is estimated at only 362 to 406 animals. Its largest group of sites is the Kien Luong karst. A 2012 report counted at least 223 langurs there. Phu Quoc Island held an estimated 31 to 44 in 2010.
A 2011 study called it probably Laos's rarest, most threatened monkey.
The IUCN assessed it as Endangered in 2015, under criteria A2cd+3cd. It suspects a decline of more than half over 36 years. It suspects that decline will continue.
Major Threats
Hunting and habitat loss are the main threats. People hunt it for traditional medicine and the pet trade. It is also eaten locally.
In Cambodia, forests are being cleared for plantations and small farms. From 2001 to 2019, Cambodia lost 1.23 million ha of tree cover. That is about 3 million acres. About 23% of forest cleared to 2015 became rubber plantations.
In Laos, hunting is the most severe threat.
In Vietnam, limestone quarrying threatens its largest population. Quarrying will destroy habitat used by half of those langurs. Hunting and habitat loss wiped out the Mui Ca Mau population.
Only 23 were recorded in trade in Vietnam from 2008 to 2013. The true number is likely much higher.
Conservation Efforts
Germain's langur is listed on CITES Appendix II. Vietnam added it to Appendix I of Decree 64 in 2019. Laos's 2007 wildlife law lists it as Prohibited. A 2005 Thai checklist lists it as Near Threatened.
Cambodia's 2007 Prakas lists it as "Common", under an old name. Hunting in Cambodian protected areas is illegal, but rarely enforced.
It lives in many protected areas. They include Keo Seima, Prey Lang and the Cardamom parks in Cambodia. Others are Huai Kha Khaeng in Thailand and Phu Quoc in Vietnam.
The IUCN calls for wider surveys and taxonomic study. Its boundary with the Annamese silvered langur still needs mapping.
Explore more monkeys starting with G. Or browse all types of monkeys.
Common Questions
Germain's langur lives west of the Mekong, from Thailand to southern Vietnam.
Germain's langur has pale gray fur and a slaty-black face. A creamy-yellow halo surrounds the face.
Germain's langur infants are born golden-orange. Their faces, hands and feet are white.
Germain's langur eats mostly young leaves. It also eats fruit, mature leaves and flowers.
Yes. The IUCN assessed Germain's langur as Endangered in 2015. Hunting and habitat loss threaten it.
Germain's langur has a slaty-black face. The Annamese silvered langur has a gray face.
Cite this page
BioExplorer. (2026, November 2). Germain’s Langur. https://www.bioexplorer.net/animals/mammals/monkeys/germains-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.