Trachypithecus geei

Geographic Range

The geographic range of golden langurs is limited to Assam, India and neighboring Bhutan where they live year-round. The area they inhabit is restricted to the region surrounded by four geographical landmarks: the foothills of Bhutan (north), Manas river (east), Sankosh river (west), and Brahmaputra river (south).

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Golden langurs occupy moist evergreen and tropical deciduous forests as well as some riverine areas and savannas in Assam and Bhutan. They are very much dependent on trees, living in the upper canopy of sub-tropical forests in the south and in more temperate forests in the north. The elevations they inhabit also vary according to their geographic range. They may be found at elevations close to sea level in the south and up to 3000 m at the foothills of Bhutan in the north. Aside from their natural habitats, golden langurs can also be found in wildlife reserves in both India and Bhutan. In Bhutan, a combination of four different national parks and wildlife sanctuaries comprise most of the area in which golden langurs are found. In Assam, they inhabit the two wildlife sanctuaries there, as well as parts of fragmented reserve forests, proposed reserve forests, and other non-forested areas.

• Habitat Regions
• temperate temperate
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• rainforest rainforest

• Other Habitat Features
• riparian riparian

Physical Description

Golden langurs can be most easily recognized by the color of their fur, after which they are named. Their hair ranges from dark golden to creamy buff and their faces are black and hairless except for a long pale beard. The color of their fur differs across their bodies with a slightly darker red on the top and sides and a lighter color underneath. It has been noted that their fur changes colors according to the seasons. In the winter it is dark golden chestnut and in the summer it is more cream colored. The color of the young also differs from adults in that they are almost pure white. Color varies geographically. Golden langurs in the south tend to be more uniform in color and smaller than those in the northern regions.

The overall shape of this monkey is slim, with long limbs and tail. The tail has a tassle on the end and is notably larger in males than in females. Males also tend to be slightly larger than females, although no weights have been recorded. The head and body measures from 50 to 75 cm and the tail ranges from 70 to 100 cm.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• ornamentation ornamentation

Reproduction

Because they have been studied relatiely little, there is little known information on the reproduction of golden langurs. Scientists believe that their reproduction is similar to a close relative of golden langurs, hanuman langurs .

• Mating System
• cooperative breeder cooperative breeder

Although not much is known about the reproduction of golden langurs, it has been observed that births occur almost year-round. There may be a period of a few months where more births are concentrated, corresponding to a change in the climate and vegetation. Golden langurs give birth to a single offspring at a time.

• Key Reproductive Features
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

While parental care of the offspring has not been observed for golden langurs, it is presumed to be similar to that of hanuman langurs . In this species, all of the care for the young is provided by the mother and other females in the group. The father has no contact with his offspring.

• Parental Investment
• precocial precocial
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• extended period of juvenile learning

Lifespan/Longevity

Due to their rarity and fairly recent discovery, golden langurs have not been well studied, and as a result little is known about their lifespan.

Behavior

Unlike hanuman langurs that are not afraid to live among humans, golden langurs tend to be a shy species that avoids humans. This makes it difficult to observe many of their behaviors and what can be noted may be unnaturally influenced by the presence of humans. It is known that they are diurnal and mostly active in the early morning and afternoon, which is when they feed. They spend most of their time in the canopy of trees and move around by leaping from branches by pushing off with their hind limbs and landing with all four limbs. They may also move along quadrupedally, both when they descend and on larger branches of trees.

Golden langurs tend to live in groups that range anywhere from 4 to 40 members, with an average group size of 8. Although not much is known about the social structure of the groups, it has been noted that social grooming is a very important group activity. Golden langurs use social grooming as a way to strengthen the bonds between members of their group.

• Key Behaviors
• arboreal arboreal
• diurnal diurnal
• motile motile
• sedentary sedentary
• social social

Home Range

There is not a great deal of information about the home range of a specific group of golden langurs. Within each group, they tend to stay in the same place and do not move far from their home.

Communication and Perception

Again, little is known about the communication between golden langurs. What is certain is that vocal communication does exist between members of the species, including loud “whooping” noises heard from the male langurs.

In spite of a paucity of information on these animals, we can assume that like other primates tactile communication (such as grooming, mating, aggressive behaviors) and visual signals (such as body postures and facial expressions) play some role in communication also.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Golden langurs are both folivores and frugivores. Their diets consist of ripe and unripe fruits, young and mature leaves, leaf buds, flower buds, seeds, twigs, and flowers. Although they eat a variety of food, they mostly prefer to eat young leaves. The most popular vegetation among golden langurs are Ficus racemosa , Salmalia malabarica , and Adenanthera peuonina . Most langurs, Trachypithecus geei included, are also known as leaf monkeys; a name derived from their exclusively vegetarian diet. Due to the large amounts of leafy material that the golden langurs consume, they have a sacculated stomach, which is a common characteristic in the subfamily Colobinae . A sacculated stomach is made up of different compartments and helps to break down the cellulose in the leaves. It is a very important feature that is necessary to obtain the maximum possible nutrition from innutritious leaves.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore

• Plant Foods
• leaves
• fruit
• flowers

Predation

Predation by other animals is negligible, most likely due to the highly arboreal lifestyle of golden langurs. Their numbers are mainly threatened by humans through fragmentation and the eventual degradation of their habitats.

Ecosystem Roles

Due to the lack of research, the role that golden langurs play in the ecosystem is unknown. Researchers do suspect however, that like most primates, they are important for seed dispersal, seed predation, and pollination.

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

Because golden langurs tend to avoid human contact, little is known about the economic importance they provide for humans.

Economic Importance for Humans: Negative

Although the limited contact between humans and golden langurs restricts the amount of information available on their economic importance, the continued destruction of their habitat may lead to more encounters. In areas where their habitat is being destroyed golden langurs may be forced to move to unfamiliar places, resulting in the destruction of crops as they search for food.

• Negative Impacts
• crop pest

Conservation Status

Golden langurs as a species are in trouble, and this is reflected by their status on various environmental lists. In 2003, they were considered engendered by the IUCN Red List, and listed as Appendix I on the CITES website. They were first listed as endangered on the IUCN Red List in 1976. In the Indo-US Primate Project Survey, which looked at the species from 1994 to 1999, they were listed as critically endangered.

The main reason for low numbers of golden langurs is because of their localized habitat and the rapid loss of this habitat due to deforestation. Although the forests are supposedly protected, until recently their protection was not strictly enforced and it is estimated that approximately 50% of their habitat was lost from India in a span of 10 to 12 years. In 1998, approximately 4,500 golden langurs remained in both Assam and Bhutan. In spite of the need for immediate action, it was reported that the area the species inhabited shrunk again from 1998 to 2002.

Although at current rates of decline, the survival of these animals seems bleak, there has been some efforts to save them. Almost all of the land they occupy in Bhutan is part of four different wildlife preserves and national parks that have been set up to protect them. The Royal Manas National Park, Black Mountain National Park, Trumsingla Wildlife Sanctuary and Phipsoo WLS are home to more than half of the total number of golden langurs living today. While this is good news, in India, only approximately 95 square km of their habitat is protected by the two WLS in Assam: the Manas WLS and Chakrasilla WLS. Most of the golden langurs' habitat falls into forest reserves and proposed forest reserves or other fragmented areas where many trees have been cut down. In the past these areas were not well protected but certain conservation groups, along with the Indo-US Primate Project are working together to assure the future of these forests. Aside from protecting the forest reserves, they are also working with local residents to rebuild the forests. With all this work being done to save golden langurs, hopefully their populations will grow.

Other Comments

Golden langurs are a species that has had multiple scientific names. For now, they are associated with the genus Trachypithecus , but when they were first discovered in 1956, they were placed under the genus Presbytis . They have also been placed in the genus Semnopithecus . Golden langurs' scientific name comes from the man who discovered them, E. P. Gee. All three of the genus names fall under the subfamily Colobinae and the family Cercopithecidae .

Additional Links

Encyclopedia of Life

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Matthew Wund (editor), University of Michigan-Ann Arbor.

Shivani Raval (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

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Srivastava, A., J. Biswas, P. Bujarbarua. 2001. Status and distribution of golden langurs (Trachypithecus geei) in Assam, India. American Journal of Primatology , 55(1). September: 15-23.

Wangchuk, T., D. Inouye, M. Hare. 2003. A new subspecies of golden langur (Trachypithecus geei) from Bhutan. Folia Primatologica , 74(2). March-April: 104-108.

Academic Press Inc. 1967. A Handbook of Living Primates . London: Academic Press Inc..

K K Gurung. 1996. Field Guide to the Mammals of the Subcontinent . London: Academic Press Inc..

Britsh Museum (Natural History). 1992. The Mammals of the Indomalayan Region . New York: Oxford University Press.

Time Inc. 1965. The Primates . New York: Time Inc..

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Aranyak. 2002. "Non-Human Primates in Northeast India" (On-line). Aaranyak. Accessed October 13, 2004 at http://www.aaranyak.org/Primates.htm .

International Union for Conservation of Nature and Natural Resources. 2003. "The IUCN Red List of Threatened Species" (On-line). Accessed February 09, 2004 at http://www.redlist.org .

Indiaprofile.com. 2001. "The Monkey With the Golden Touch" (On-line). India Profile. Accessed February 04, 2004 at http://www.indiaprofile.com/wildlife/goldenlangur.htm .

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