Trachypithecus geeigolden leaf monkey

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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). ("Non-Human Primates in Northeast India", 2002; Gupta and Chivers, 2000; Srivastava, et al., 2001)

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. ("Nature Wildfacts - Golden langur, golden leaf monkey", 2004; "Wildlife Database", 2003; Srivastava, et al., 2001; Wangchuk, et al., 2003)

  • Range elevation
    0 to 3000 m
    0.00 to 9842.52 ft

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. ("Nature Wildfacts - Golden langur, golden leaf monkey", 2004; "Non-Human Primates in Northeast India", 2002; "Field Guide to the Mammals of the Subcontinent", 1996; Wangchuk, et al., 2003)

  • Average mass
    8100 g
    285.46 oz
    AnAge
  • Range length
    120 to 175 cm
    47.24 to 68.90 in

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. ("A Handbook of Living Primates", 1967)

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. ("A Handbook of Living Primates", 1967)

  • Breeding interval
    The breeding interval is unknown.
  • Breeding season
    The breeding season is year-round.
  • Range number of offspring
    1 (high)
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge

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. ("A Handbook of Living Primates", 1967)

  • Parental Investment
  • 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. ("Nature Wildfacts - Golden langur, golden leaf monkey", 2004)

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. ("Nature Wildfacts - Golden langur, golden leaf monkey", 2004; Gupta and Chivers, 2000; "The Monkey With the Golden Touch", 2001; "Field Guide to the Mammals of the Subcontinent", 1996)

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. ("The Monkey With the Golden Touch", 2001; "Field Guide to the Mammals of the Subcontinent", 1996; Srivastava, et al., 2001)

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. ("Non-Human Primates in Northeast India", 2002; Srivastava, et al., 2001)

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. ("A Handbook of Living Primates", 1967)

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. ("Nature Wildfacts - Golden langur, golden leaf monkey", 2004; "A Handbook of Living Primates", 1967; Gupta and Chivers, 2000; "The Primates", 1965)

  • 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. ("The Monkey With the Golden Touch", 2001)

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. ("Non-Human Primates in Northeast India", 2002)

  • Ecosystem Impact
  • disperses seeds
  • pollinates
Species Used as Host
  • Unknown
Mutualist Species
  • Unknown
Commensal/Parasitic Species
  • Unknown

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. ("CITES-listed species database", 2004; "Non-Human Primates in Northeast India", 2002; "The IUCN Red List of Threatened Species", 2003)

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. ("Non-Human Primates in Northeast India", 2002; Gupta and Chivers, 2000; Srivastava, et al., 2001)

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. ("Wildlife Database", 2003; "Non-Human Primates in Northeast India", 2002; Gupta and Chivers, 2000)

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. ("Wildlife Database", 2003; "The Mammals of the Indomalayan Region", 1992; "The Monkey With the Golden Touch", 2001)

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.

Glossary

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

cooperative breeder

helpers provide assistance in raising young that are not their own

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

young precocial

young are relatively well-developed when born

References

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..

2004. "CITES-listed species database" (On-line). Convention of International Trade in Endangered Species of Wild Fauna and Flora. Accessed February 09, 2004 at http://www.cites.org/eng/resources/species.html.

2004. "Nature Wildfacts - Golden langur, golden leaf monkey" (On-line). BBC - Nature Wildfacts. Accessed February 09, 2004 at http://www.bbc.co.uk/nature/wildfacts/factfiles/323.shtml.

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.

2003. "Wildlife Database" (On-line). Janmanch. Accessed February 09, 2004 at http://www.janmanch.org/wildlife/kids_w_l.asp?id=65.

Gupta, A., D. Chivers. 2000. Feeding ecology and conservation of the golden langur. Journal of the Bombay Natural History Society, 97(3). December: 349-362.

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.