Brenda de Groot

Germain’s Langur

The very first primate article is a fact! And how to start this series of happiness featuring a species that I studied myself? That’s right – I love monkeys so much that I completed a Masters course in primatology. And this monkey species was the chosen one for my final project. Let me introduce to you: the Germain’s langur.

What is a Germain’s Langur?

Indochinese silvered langur illustration - Vegan MonkyPerhaps you’ve never heard of a ‘langur’ before. In that case you are lucky, because then you have a whole lot still to explore about my all time favourites. In short, a langur is a monkey that primarily feeds on leavens and lives in Asia. There are many different species of langurs, of which the Germain’s langur is one.

The Germain’s langur has a grey coat and black hands and forearms. It’s face is black as well, and because of the high eyebrow-ridge, the monkey has a permanently surprised look on its face. Now there are a lot of leaf-eating Asian primates that look alike the Germain’s langur, but the feature that makes this monkey stand out are the long white whiskers that form a triangle around its face.

Sadly, this animal is still quite unknown. At the time I started my research, even data on its behaviour and biology lacked for this species. And that while they are seriously threatened with extinction! Without basic information it is difficult for scientists and conservationists to take action to protect them.

The lack of information and their Endangered conservation status were the most important reasons that I chose this species of langur to conduct research on during my Primate Conservation course. So everything I write here is shameless self-promotion, since the majority of the information comes from the artikel I got published 🙂 .



Scientific name:
Trachypithecus germaini

Other names:
Indochinese lutung, Indochinese silvered langur, Indochinese leaf-monkey


Kingdom: Animalia (animals)
Phylum: Chordata (vertebrate)
Class: Mammalia (mammals)
Order: Primates (monkeys/apes)
Family: Cercopithecidae (Old World monkeys)
Subfamily: Colobinae (leaf-monkeys)
Genus: Trachypithecus (lutungs)
SpeciesTrachypithecus germaini


Germain’s langurs live in southeast Thailand, Cambodia, southern Vietnam, Myanmar and southern Laos. They roam around lowland forests of different types:

  • Evergreen forests
  • Semi-evergreen forests (that shed their leaves in dry season)
  • Mixed forest
  • Riverine forests

Click here to view an interactive map of their range.

Behaviour and Biology

Like all other langurs, the Germain’s langur spends most of its time high up in the trees, where they love to feed on fresh, young leaves. The langur group I studied quite often descended to the ground to eat grass, leaves of shrubs, or to go – as I called it – mushroom hunting (I’ll come back to that in a minute).

The langurs live a life Garfield would be jealous of:

  • 47% of their waking time they spend munching away food
  • 44% of the time they rest (sit in the tree)
  • They walk, climb, jump or run only 5% of their time
  • Grooming takes about 4% of their time, which is less then for frugivorous primates


Germain’s langurs mainly eat young leaves, supplemented with fruit and flowers. A langur’s stomach is specialised in processing fibrous and sometimes poisonous leaves. The bacteria in their stomachs break down the material more effectively than those of other monkey species.

But this monkey also shows some curious eating habits. I have seen them eating raw mushrooms and soil more than once! Thanks to their specialised stomachs, langurs can digest the nutrients from mushrooms. And the do not pick them thoughtlessly from the ground: the group I observed really went on mushroom hunting sessions. About once every week they would spend about half of the afternoon searching and eating mushrooms.

Social Structure

Germain’s langurs live in small family groups, like other langurs do. The langur groups are generally led by one adult male. Every other year, females give birth to one orange baby. Yes, you heard that right. This amazing characteristic is one of the reasons why I love langurs so much:

Orange babies



Langur babies (or actually only those of the genus Trachypithecus) has a bright orange coat for the first 6 months of his new life. As the monkey grows older, the colour of its fur changes, and after half a year all the orange fluff made place for grey hairs. Why langur babies have such a bright orange fur, I’ll tell you all about in another article on the genus Trachypithecus.

Unknown monkey species

Although it looks like there is quite some data on Germain’s langurs, there still is a lot more research needed on their biology and behaviour in the wild. When you would compare the information there is on apes and frugivorous monkey species, the data available for langurs – especially Germain’s langus – is modest to say at least. The lack of data is due to a combination of factors, most likely being:

Logo-11. They are a little bit boring

Langurs eat leaves, and they need to eat lots of them to gain enough energy. Therefore they spend a big part of their waking lives eating. After they fed on the leaves, the langus need to digest the food. So the next big chunk of time goes to sitting on a branch. There is not much time left for grooming, squabble or power struggles, for which frugivorous monkeys are so popular for. Researchers are human too, and the apes (chimpanzees!) and fruit-eating monkeys are the uncontested front runners when it comes to information and attention.

I personally find this lack of group friction what makes langurs so beautiful. They are very peaceful primates. And in the rare event of a quarrel, one of them would slap the other – who then slaps back or screems once, and that was it. Then they just continue their lives like nothing happened. No continuous stress or pseudo friendships for the sake of power, like the way their frugivorous relatives live. That it means that there is less going on is really fine by me.

2. They are difficult to study

Germain’s langurs are hard to find because of their arboreal and quiet way of living. You really have to look hard to spot them high up in the trees. Many frugivorous monkeys and apes are louder and can be found on the ground most of the time.

Besides that, Cambodia was trapped in the regime of Pol Pot, just by the time primatology as a study began to thrive. As a foreigner and intellectual, you really didn’t want to be found by the Red Khmer, somewhere in a deserted forest..


Like I mentioned before, the Germain’s langur is threatened with extinction, and like almost all Endangered animal species, humans are the cause of this.

Germain’s langur threats:

  • Illegal hunting for meat
  • Illegal hunting for traditional ‘superstition’ medicine
  • Illegal hunting for (likewise illegal) wildlife trade
  • Habitat loss

If you want to take action to do something about this: you can. You can always make a donation to a charity that devotes its time and effort to protect the Germain’s langur, such as the Endangered Primates Rescue Centre in Vietnam, or larger conservation organisations like Greenpeace and WWF. You can also take action yourself, by studying primatoloy or primate conservation! Especially the latter I highly recommend 😉


Arkive: https://www.arkive.org/germains-langur/trachypithecus-germaini/
WWF Cambodia: https://cambodia.panda.org/projects_and_reports/endangered_species/mammals/silver_langur/
IUCN Red List of Threatened Species: https://www.iucnredlist.org/details/39874/0

Some More Pictures I’d Love to Show You

Indochinese langoer illustratie

This post is also available in NL

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