Hoolock gibbon
Encyclopedia
The hoolock gibbons also known as hoolocks, are two primate
species from the family of the gibbons (Hylobatidae).
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 the eyes and around the mouth give their face a mask-like appearance.
The range of the hoolocks is the most northwestern of all the gibbons, extending from North-East India
, to Myanmar
. Small populations (in each case few hundred animals) live also in eastern Bangladesh
and in southwest China
. In North-East India, the hoolock is found south of Brahmaputra and east of Dibang rivers. Its range extends into seven states covering Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura..
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 seven month gestation, with a milky white or buff colored hair. After about six months the hair of males will darken and turn black, while the female hair remains buff colored throughout her life. After 8 to 9 years they are fully mature and their fur reaches its final coloration. Their life expectancy in the wild is about 25 years.
. 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 hoolocks are not closely related to B. sericus and so have been placed in their own genus, Hoolock. In the process, the two subspecies of hoolocks have been raised to species level.
There are two species of Hoolock:
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
species from the family of the gibbons (Hylobatidae).
Hoolocks are the second largest of the gibbons, after the Siamang
Siamang
The siamang is a tailless, arboreal, black-furred gibbon native to the forests of Malaysia, Thailand, and Sumatra. The largest of the lesser apes, the siamang can be twice the size of other gibbons, reaching 1 m in height, and weighing up to 14 kg...
. 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 the eyes and around the mouth give their face a mask-like appearance.
The range of the hoolocks is the most northwestern of all the gibbons, extending from North-East India
North-East India
Northeast India refers to the easternmost region of India consisting of the contiguous Seven Sister States, Sikkim, and parts of North Bengal...
, to Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
. Small populations (in each case few hundred animals) live also in eastern Bangladesh
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
and in southwest China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. In North-East India, the hoolock is found south of Brahmaputra and east of Dibang rivers. Its range extends into seven states covering Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura..
Like the other gibbons, they are diurnal
Diurnal animal
Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
and arboreal, brachiating
Brachiation
Brachiation is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms.- Brachiators :...
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 seven month gestation, with a milky white or buff colored hair. After about six months the hair of males will darken and turn black, while the female hair remains buff colored throughout her life. After 8 to 9 years they are fully mature and their fur reaches its final coloration. Their life expectancy in the wild is about 25 years.
Classification
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 SiamangSiamang
The siamang is a tailless, arboreal, black-furred gibbon native to the forests of Malaysia, Thailand, and Sumatra. The largest of the lesser apes, the siamang can be twice the size of other gibbons, reaching 1 m in height, and weighing up to 14 kg...
. 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
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
for Bunopithecus is Bunopithecus sericus
Bunopithecus sericus
Bunopithecus sericus is an extinct gibbon or gibbon-like primate. Its remains were first discovered in Sichuan, China, in strata from the Middle Pleistocene, but have since been found all over Southern Europe and Asia...
, an extinct gibbon or gibbon-like ape from Sichuan
Sichuan
' , known formerly in the West by its postal map spellings of Szechwan or Szechuan is a province in Southwest China with its capital in Chengdu...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
. Very recent investigations have shown that the hoolocks are not closely related to B. sericus and so have been placed in their own genus, Hoolock. In the process, the two subspecies of hoolocks have been raised to species level.
There are two species of Hoolock:
- Western Hoolock GibbonWestern Hoolock GibbonThe western hoolock gibbon is a primate from the Hylobatidae family. The species is found in Assam, Bangladesh and in Myanmar west of the Chindwin River.-Classification:...
, Hoolock hoolock - Eastern Hoolock GibbonEastern Hoolock GibbonThe eastern hoolock gibbon is a primate from the Hylobatidae family. The species is found in extreme eastern corner of Assam and parts of Arunachal Pradesh, Myanmar east of the Chindwin River, and in south west Yunnan of China....
, Hoolock leuconedys