The western hoolock gibbon (''Hoolock hoolock'') is a

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...

from the gibbon family, Hylobatidae. The species is found in

Assam Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...

Mizoram Mizoram () is a state in Northeast India, with Aizawl as its seat of government and capital city. The name of the state is derived from "Mizo", the self-described name of the native inhabitants, and "Ram", which in the Mizo language means "lan ...

, and

Meghalaya Meghalaya (, or , meaning "abode of clouds"; from Sanskrit , "cloud" + , "abode") is a state in northeastern India. Meghalaya was formed on 21 January 1972 by carving out two districts from the state of Assam: (a) the United Khasi Hills and J ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

, and

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

west of the Chindwin River.

Classification

Mootnick and Groves stated that hoolock gibbons do not belong in the genus ''

Bunopithecus ''Bunopithecus'' is an extinct genus of primate represented by one species, ''Bunopithecus sericus'', a gibbon or gibbon-like ape. Its remains were first discovered in Sichuan, China, in strata from the Middle Pleistocene. Although the three hoo ...

'', and placed them in a new genus, ''

Hoolock The hoolock gibbons are three primate species of genus ''Hoolock'' in the gibbon family, Hylobatidae, native to eastern Bangladesh, Northeast India, Myanmar, and Southwest China. Description Hoolocks are the second-largest of the gibbons, after ...

''. This genus was argued to contain two and later three distinct species, which were previously thought to be subspecies: ''H. hoolock'', '' H. leuconedys'', and '' H. tianxing''. A larger evolutionary distance was later found to exist between these three species and the white-handed gibbons than between bonobos and chimpanzees. A new subspecies of the western hoolock gibbon has been described recently from northeastern India, which has been named the Mishmi Hills hoolock gibbon, ''H. h. mishmiensis''.

Vocalisation

Like other gibbons, hoolock gibbon pairs produce a loud, elaborate song, usually as a duet from the forest canopy, in which younger individuals of the family group may join. The song includes an introductory sequence, an organising sequence, and a great call sequence, with the male also contributing to the latter (unlike in some other gibbon species).

Habitat

In India and Bangladesh, it is found where the canopy is contiguous, broad-leaved, wet evergreen and mixed evergreen forests, including dipterocarp forests and often in mountainous terrain. The species is an important seed disperser; its diet includes mostly ripe fruits, with some flowers, leaves, and shoots.

Conservation

Numerous threats exist for western hoolock gibbons in the wild, and they are now entirely dependent on human action for their survival. Threats include habitat encroachment by humans, forest clearance for

tea Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of ''Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of southwestern China and north ...

cultivation, the practice of ''jhuming'' (slash-and-burn cultivation), hunting for food and "medicine", capture for trade, and

forest degradation Forest degradation is a process in which the biological wealth of a forest area is permanently diminished by some factor or by a combination of factors. "This does not involve a reduction of the forest area, but rather a quality decrease in its c ...

. Since the 1980s, western hoolock gibbon numbers are estimated to have dropped from more than 100,000 (Assam alone was estimated to have around 80,000 in the early 1970s) to less than 5,000 individuals (a decline of more than 90%). In 2009 it was considered to be one of the 25 most endangered primates, though it has been dropped from the later editions of the list.

References

{{Taxonbar, from=Q577084 western hoolock gibbon Primates of South Asia Mammals of Bangladesh Mammals of Myanmar Mammals of India Endangered fauna of Asia Species endangered by the pet trade western hoolock gibbon Taxa named by Richard Harlan

Classification

Vocalisation

Habitat

Conservation

See also

References