The living primates at Gibbon Wildlife Sanctuary

Ahom Dynasty, who ruled the civilization of Brahmaputra Valley for nearly 60 decade’s during the 12th Century AD; their last capital was Jorhat, “The Cultural Capital of Assam”. Jorhat is now the gateway for the first island district of India ‘Majuli’. Out of the way from Jorhat locates the Gibbon Wildlife Sanctuary a.k.a. Hollongapar Gibbon Sanctuary or Hollongapar Reserve Forest which is approximately 24 kilometers away from its Town Centre. Surrounded by tea gardens, Gibbon Wildlife Sanctuary is an isolated protected area covering an area of only 20.98 sq km. It might fall under the category of Small Sanctuary but is one of the rare sanctuaries active under the tropical region. It got its recognition in the year 1997 and is the home to some of the living primates the western hoolock gibbon and the capped langur.


The western hoolock gibbons are a primate from the gibbon family, Hylobatidae. Hoolocks are the second-largest of the gibbons. Hoolock gibbon is the only Ape which does not have a tail and lives on trees. They have long and slender arms and are swift creature which results them barely needing to step on the ground. They reach a size of 60-90 cm and weigh 6 -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. 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 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 eight to 9 years, they are fully mature and their fur reaches its final coloration. Their life expectancy in the wild is about 25 years. Like other gibbons, hoolock gibbon pairs produce a loud, elaborate song, usually sung as a duet from the forest canopy, in which younger individuals of the family group may join in. The song includes an introductory sequence, an organizing sequence, and a great call sequence, with the male also contributing to the latter.


The capped langur is an herbivore that specializes in eating leaves, but fruit also is a major component of their diet. In northeastern India, capped langurs mainly fed on young leaves of various trees, shrubs, and climbers, and on seeds and flowers. This species eats a large amount of mature leaves as well as immature leaves when they are available. Bark of tender twigs has been observed to be consumed by this species. They are diurnal and an arboreal species.

Extinction of this wonderful species completely depends on the behavior of human actions, as threats are always high for them to survive. Some of the threats include habitat encroachment by humans, forest clearance for tea cultivation, the practice of jhum cultivation etc. We humans as being a part of the primate’s family should be responsible to save the hoolock from extinction.  Over the past 40 years, population of western hoolock gibbon is estimated to have dropped by 90% and 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. That is the reason on 1997 the Government of Assam upgraded the status of the Hoollongapar Reserve Forest to Gibbon Wildlife Sanctuary, making this the first Protected Area ever named after a primate species.

Pic Credit – Jishnu Bora

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