April 2014

Name: Hoolock Gibbon
Scientific Name: Hoolockhoolock (Western Hoolock Gibbon)
Hoolockleuconedys (Eastern Hoolock Gibbon)

Profile: Hoolocks happen to be the second-largest members of the gibbons’ family, of sizes between 60 cm to 90 cm. The male and female of the species are similar in size but vary considerably in terms of coloration. The average life expectancy of Hoolock gibbons is about twenty-five years. Hoolock gibbons possess slender, long arms which allow them to move swiftly from one tree to another at high speed.

Habitat: There are two distinct species of Hoolock gibbons; however they are often confused as one species. In terms of habitat, the species inhabit separate regions in India. The Western Hoolock gibbon appears to be far more extensive since it can be found in all the North-eastern states of India.

The presence of the Western Hoolock is limited between the south of the River Brahmaputra and the eastern part of the River Dibang. On the other hand, the Eastern Hoolock inhabits certain areas of Assam and Arunachal Pradesh.

Habits: Hoolocks are famed for their emotive call which echoes across vast distances in the forest. It is mainly used by the creatures to draw the attention of potential mates. Female Hoolocks give birth to a single offspring and the baby remains within the family group up to seven to ten years.

Diet: The diet of the Hoolock gibbon mainly comprises of fruits but they will occasionally consume shoots, flowers and leaves. In some cases, Hoolock gibbons even feed on insects.

Ecological Importance: The Western Hoolock gibbon is currently listed as an endangered species on the IUCN Redlist while the Eastern Hoolock has been marked as ‘Vulnerable’. The populations of both species, however, have been declining rapidly owing to the destruction of their natural habitats as well as the different forms of hunting which are practiced for their meat.The population of the Western Hoolock gibbon has declined significantly over the course of the past thirty years by almost 90%, and it is currently believed to be among the top twenty-five endangered primate species in the whole world. The Hoolock gibbon benefits indirectly from the protection initiatives of WWF-India.

My first encounter with the Hoolock Gibbon took place on an early December morning while I was driving towards the Burapahar Range in Kaziranga NP, with some keen wildlife enthusiasts from Germany. Our guide noticed a bunch of caped langurs and the car was halted so we could get down and take a closer look at them. Suddenly, the stillness of the air was broken by a loud sound of howling from the jungle. Our initial thought was that someone was making fun of us through such weird sounds but our guide explained to us that this was the call of the Hoolock gibbons. His words proved true as we noticed them emerging from the jungle after a few minutes. The way they swung nimbly from branch to branch reminded me of Tarzan. They started feeding on fruits from the trees. I came to know that these creatures enjoy an easy lifestyle by nature.