| Hoolock gibbons [1] [2] | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Haplorhini |
| Infraorder: | Simiiformes |
| Family: | Hylobatidae |
| Genus: | Hoolock Mootnick & Groves, 2005 |
| Species | |
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.
Hoolocks are the second-largest of the gibbons, after the siamang. They reach a size of 60 to 90 cm and weigh 6 to 9 kg. The sexes are about the same size, but they differ considerably in coloration; males are black-colored with remarkable white brows, while females have a grey-brown fur, which is darker at the chest and neck. White rings around their eyes and mouths give their faces a mask-like appearance. The Oxford English Dictionary says that the name "hoolock" is from "a language of Assam."
In northeast India, the hoolock is found south of Brahmaputra and the North Bank areas and east of the Dibang Rivers. [4] Its range extends into seven states covering Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura (The seven northeastern states of India). [5] [6] The species are protected in India in the Hollongapar Gibbon sanctuary, which support 125 Individuals of the species, as of 2023. [7] In Bangladesh, the western hoolock gibbons were distributed across 35 forest fragments. The largest of these (Lawachara and Kaptai) supported 42 and 84 individuals respectively, but 17 of the fragments had less than ten individuals. For a better overview the forest fragments are grouped into 13 areas. All areas are located within Chittagong and Sylhet divisions, mostly near the eastern border of the country. In China, in historical times, the skywalker gibbon was recorded in nine counties in the west bank of the Salween River in westernmost Yunnan province. Based on more recent interview surveys conducted in October–November 2008 and field surveys conducted in Mar, Apr, and Aug 2009, the current Chinese population of hoolock gibbons was found to be restricted to three counties (Baoshan, Tengchong, and Yingjiang). The population size was estimated to be less than 200 individuals. In Myanmar, all three species of hoolock gibbon can be found in the forested areas west of Thanlwin river. Of all four distribution countries, Myanmar holds the key population of all three species. [8]
Like the other gibbons, they are diurnal and arboreal, brachiating through the trees with their long arms. They live together in monogamous pairs, which stake out a territory. Their calls serve to locate family members and ward off other gibbons from their territory. Their diet consists mainly of fruits, insects and leaves.
Young hoolocks are born after a 7-month gestation, with milky white or buff-colored hair. After about 6 months, the hair of males darkens and turns black, while the females' hair remains buff-colored throughout their lives. After 8–9 years, they are fully mature and their fur reaches its final coloration. Their life expectancy in the wild is about 25 years.
The classification of this gibbon has changed several times in the past few years. Classically, all gibbons were classified in the genus Hylobates, with the exception of the siamang. After some studies, the genus was divided into three subgenera (including the siamang's Symphalangus), and then into four (recognizing Bunopithecus as the hoolock subgenus distinct from other gibbon subgenera). These four subgenera were elevated to full genus status. However, the type species for Bunopithecus is Bunopithecus sericus , an extinct gibbon or gibbon-like ape from Sichuan, China. Very recent investigations have shown that the hoolock gibbons are not closely related to B. sericus, so they have been placed in their own genus, Hoolock. In the process, the two subspecies of hoolock gibbons have been raised to species level. [1] [2] 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. hoolock mishmiensis. [9] A further new species, H. tianxing, with an estimated population of about 200, was discovered in southwest China in 2017. [10]
The species of hoolock are: [2] [10]
| Common name | Scientific name and subspecies | Range | Size and ecology | IUCN status and estimated population |
|---|---|---|---|---|
| Western hoolock gibbon | Hoolock hoolock (Harlan, 1834) | India, Bangladesh, and Myanmar | Size: Habitat: Diet: | EN |
| Eastern hoolock gibbon | Hoolock leuconedys (Groves, 1967) | China(Yunnan) and India | Size: Habitat: Diet: | VU |
| Skywalker hoolock gibbon | Hoolock tianxing [3] Fan et al., 2017 | Myanmar and southwestern China | Size: Habitat: Diet: | EN
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Gibbons are apes in the family Hylobatidae. The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforests from eastern Bangladesh to Northeast India to southern China and Indonesia.
Apes are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia, which together with its sister group Cercopithecidae form the catarrhine clade, cladistically making them monkeys. Apes do not have tails due to a mutation of the TBXT gene. In traditional and non-scientific use, the term ape can include tailless primates taxonomically considered Cercopithecidae, and is thus not equivalent to the scientific taxon Hominoidea. There are two extant branches of the superfamily Hominoidea: the gibbons, or lesser apes; and the hominids, or great apes.
The siamang is a endangered arboreal, black-furred gibbon native to the forests of Indonesia, Malaysia, and Thailand. The largest of the gibbons, the siamang can be twice the size of other gibbons, reaching 1 m (3.3 ft) in height, and weighing up to 14 kg (31 lb). It is the only species in the genus Symphalangus. Fossils of siamangs date back to the Middle Pleistocene.
The lar gibbon, also known as the white-handed gibbon, is an endangered primate in the gibbon family, Hylobatidae. It is one of the better-known gibbons and is often kept in captivity.
Müller's gibbon, also known as the southern grey gibbon, is a primate in the gibbon family, Hylobatidae.
The genus Hylobates is one of the four genera of gibbons. Its name means "forest walker", from the Greek hūlē and bates.
Nomascus is the second-most speciose genus of the gibbon family, Hylobatidae. Originally, this genus was a subgenus of Hylobates, with all individuals considered to be one species, H. concolor.
The Nokrek National Park, the core area of the Nokrek Biosphere Reserve, is a National park located approximately 2 km away from Tura Peak in West Garo Hills district of Meghalaya, India.The Nokrek Biosphere Reserve along with the Nokrek National Park was added by UNESCO to its list of Biosphere Reserves in May 2009. along with the Balpakram National Park in South Garo Hills. The Nokrek area is a hotspot of biodiversity in Meghalaya. Established in 1986, the National Park area comprising around 47.48 square kilometres is looked after by the Northern Nokrek Range and the Southern Nokrek Range under the East & West Garo Hills Wildlife Division of the Meghalaya State Forest Department under the administrative control of the Government of Meghalaya, India.
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.
The Hollongapar Gibbon Sanctuary, formerly known as the Gibbon Wildlife Sanctuary or Hollongapar Reserved Forest, is an isolated protected area of evergreen forest located in Assam, India. The sanctuary was officially constituted and renamed in 1997. Set aside initially in 1881, its forests used to extend to the foothills of the Patkai mountain range.
The eastern hoolock gibbon is a primate from the gibbon family, Hylobatidae. It is one of three species of hoolock gibbon. This species is found in east of the Chindwin River, such as the Mahamyaing Wildlife Sanctuary, and in south west Yunnan of China. Recent study published in April, 2021, in International Journal of Primatology confirmed that this species is not found in India as it was thought to be.
The western hoolock gibbon is a primate from the gibbon family, Hylobatidae. The species is found in Assam, Mizoram, and Meghalaya in India, Bangladesh, and Myanmar west of the Chindwin River.
Balpakram is located in South Garo Hills district in Meghalaya, India.
Ficus neriifolia is a species of fig (Ficus). It is native to Asia, including Bhutan, Burma, China, India, and Nepal.
The Mizoram–Manipur–Kachin rain forests is a subtropical moist broadleaf forest ecoregion which occupies the lower hillsides of the mountainous border region joining Bangladesh, China's Yunnan Province, India, and Myanmar. The ecoregion covers an area of 135,600 square kilometres (52,400 sq mi). Located where the biotas of the Indian Subcontinent and the Indochinese Peninsula meet, and in the transition between subtropical and tropical regions of Asia, the Mizoram–Manipur–Kachin rain forests are home to great biodiversity. The WWF rates the ecoregion as "Globally Outstanding" in biological distinctiveness.
The Yunnan lar gibbon, also known as the Yunnan white-handed gibbon, is a subspecies of the lar gibbon, a primate in the gibbon family, Hylobatidae. This Chinese subspecies is thought to be extinct.
Anwaruddin Choudhury is an Indian naturalist, noted for his expertise on the fauna of North-East India.
The phylogenetic split of the superfamily Hominoidea (apes) into the Hylobatidae (gibbons) and Hominidae families is dated to the early Miocene, roughly 20 to 16 million years ago.
The Skywalker hoolock gibbon or Gaoligong hoolock gibbon is an arboreal primate in the gibbon family, Hylobatidae. It is one of three species of hoolock gibbon and was first described in January 2017 in the American Journal of Primatology. The Skywalker hoolock gibbon is one of two species of Eastern hoolocks: H. tianxing and H. leuconedys. Researchers estimate H. tianxing diverged from H. leuconedys roughly 490,000 years ago. The Eastern hoolock is vulnerable on the IUCN Red List, with a population of 310,000–370,000 individuals. Of this population, H. tianxing makes up less than 150 individuals, making the Skywalker hoolock gibbon an endangered species.
