A pair of spectacled langurs in Thailand ©Getty Images

A pair of spectacled langurs in Thailand ©Getty Images

What are Langurs?

Langurs are leaf-eating monkeys, part of the primate family. There are different kinds of langurs, found in different countries in Asia. They are small agile monkeys with long prehensile tails, which means the tails can curl around branches and hold on.  Some species, or kinds, of langur are very rare.

Habitat and Distribution

Langurs usually live in the middle and upper canopies of tall trees in thick forests of India, Bhutan, Sri Lanka , Indonesia, Thailand, Vietnam, Cambodia and Laos. 

Appearance and Habits

Langurs are also called leaf monkeys ©Getty Images

Langurs are also called leaf monkeys ©Getty Images

All langurs have excellent sight and hearing. They have thumbs like those of humans, long legs, hands and feet. Their fur is longish, usually grey, black or brown, and they usually have black faces. They are active in the daytime and rarely come down from the trees.  Langurs generally feed in the mornings and late afternoons, and rarely leave the trees. Like all monkeys, members of a group groom each other. Grooming is an important part of all monkey life, and helps keep the relationships between them close. Many langur species have distinctive heads with their long fur coming to a peak on top. Their tails are very long.

Diet

The diet of langurs is mostly leaves, but they also eat fruit and flowers in season. This food is difficult to digest and does not have a high nutrition value, so langurs are not as active as some other kinds of monkey. Langurs have large stomachs that have several sections. This is because plant cells are surrounded by tough material called cellulose, which is very difficult to digest without special bacteria, which is found in the first section of the langur's stomach.

Behaviours

Many kinds of langur babies are apricot coloured for the first weeks. ©Getty Images

Many kinds of langur babies are apricot coloured for the first weeks. ©Getty Images

There are different ways that different langur species organise their groups, which are called troops. Most kinds of langur live in groups of one adult male and several females and young.  Some kinds of langurs have several males in a troop, organised into an order of importance from highest to lowest, living with females and young. There are also all male groups,  generally made up of males that can't take over a one-male group or have been pushed out of one.

Langur troops make loud calls to let other troops know where they are. Troops generally travel slowly through the treetops, feeding as they go. Some of their travel is by brachiation, or swinging through the branches.  Langurs play an important role in helping the forests in which they live regenerate because they eat seeds and  by the time the seeds come out in their poo, they are far away from the trees the seeds came from.  If threatened with danger, the dominant, or top, male will confront the danger while the rest of the troop escape.

Life cycle

Females usually give birth every 2 years, about 7 months after mating with a male. Twins are rare. Male young leave the group before they are fully adult, and travel to find a group they can join.  Langurs live for about 20 years.

A few langur species:

The common langur, also called grey langur or Hanuman langur©Getty Images

The common langur, also called grey langur or Hanuman langur©Getty Images

Common langurs

These are very common, found in the jungles of northern, western and central India. In fact, there are so many of this kind of langur that in some parts of India they have become a nuisance to humans.   They are considered to be gods by people of the Hindu faith. Common langurs are about 75cm long, and their tails are about 100 cm long.

 They weigh between 9 and 15 kg. At night each troop returns to a group of trees in its territory to sleep. They sleep in the outer branches to escape predators. They eat a variety of fruits, flowers, buds, shoots, leaves, and sap, but they also eat termites and other insects.  Females give birth in the cooler time of the year.Other females in the troop help look after the young.

Golden langur ©Getty Images

Golden langur ©Getty Images

Golden langurs

These very rare langurs are found in Bhutan and part of India, and were only discovered in the 1920s.  They live in groups of about nine. They eat mostly mature leaves according to the season,  and also eat young leaves and fruit.

Golden langurs rarely leave the trees and travel by brachiation, or swinging through the branches. Their water comes from dew or rain on leaves.

 

  Douc langurs

These critically endangered langurs are found in   Laos, Vietnam and Cambodia. They used to be found in China also. They are about 70 cm long, not including the tail. There are three species, or kinds, of douc langurs: the red-shanked  and the black-shanked, and now a new species found in 1998 which scientists have called grey-shanked douc langur.  A small population of this new group was found the southeastern part of Vietnam's Central Highlands and are listed as Critically Endangered, and are one of the 25 most endangered primates.  

Red-shanked douc langur looks like it wears red socks. ©Getty Images

Red-shanked douc langur looks like it wears red socks. ©Getty Images

Douc langurs are found in tropical rain forest and monsoon forests. Troops generally consist of up to 15, with several adult males and about twice as many females.  

Reasons that they are endangered include being hunted for food and for making traditional medicines, loss of forest habitat and the environmental disruption during the Vietnam War, when there was a great deal of bombing and chemicals sprayed by air.

Mentawai Langurs

These langurs are named for the only place they are found - the Mentawai Islands of Indonesia. They weigh about      6 - 7 kg and are found in mangrove forest and rainforests. Generally a troop consists of 3-4, just one adult pair and their young. This is very unusual in monkeys, and it appears that the Mentawai langurs pair for life. They are endangered, and the population is declining because of logging and being hunted for food.

Silvered leaf langur ©Getty Images

Silvered leaf langur ©Getty Images

Silvered leaf langurs

This kind of langur is found on the Indonesian island of Sumatra in forest and mangrove areas. Their fur is blackish grey with silvery tips.

Javan Langurs

These langurs come from Java in Indonesia. Some are black and some are brown. Young Javan langurs have apricot coloured fur when they are born, and darken to their adult colour after about 4-5 months. Much of their habitat has been destroyed, but Javan langurs have adapted to this by moving into commercial plantations of teak trees and feeding on teak leaves.

Cat Ba or golden-headed langurs

These langurs are one of the rarest primates in the world, and are listed as Critically Endangered. They are found only on the island of Cat Ba in Vietnam's Halong Bay, and there are possibly only 60 left. The island, and whole Halong Bay area, is limestone Karst forest. Limestone areas are riddled with caves, and these langurs shelter in caves. They spend one or two nights in a cave before moving on to another feeding area and a different cave.  They feed on leaves and shoots, flowers and some fruits that are poisonous to other animals, including humans.   A group will have about 12 caves in their territory. These monkeys were hunted for use in traditional medicines, but not for food because their meat has an unpleasant smell. 

Read about langurs:

http://www.animalstown.com/animals/l/langur/langur.php

Read about douc langurs of Vietnam, Laos and Cambodia (formerly called Indo China):

http://wwf.panda.org/about_our_earth/species/profiles/mammals/douc_langur/

Read about the golden langur of India and Bhutan, and watch videos:

http://www.arkive.org/golden-langur/trachypithecus-geei/

Read the kidcyber page:

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