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The 'hoolock gibbons' (''Hoolock''), 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 genders 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 Assam in North-East India, to Myanmar. Small populations (in each case few hundred animals) live also in the eastern Bangladesh and in southwest China. 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 fur. After about six months their fur turns black. 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.

Contents

Classification

References

External links

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 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 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 Gibbon, ''Hoolock hoolock''

★ Eastern Hoolock Gibbon, ''Hoolock leuconedys''

References

External links

★ ARKive - images and movies of the hoolock gibbon ''(Bunopithecus hoolock)''

★ Hoolock Gibbon photos

★ Hoolock Gibbon songs

★ Gibbon Conservation Center