Wild You Were Sleeping Episode 5: Meet The Western Hoolock Gibbon

North-East India (northeast) is the most biodiverse region in the country. The interaction of the Indo-Malayan and Palearctic biogeographic regions with the influence of the Himalayas makes the northeast one of the major biodiversity hotspots in the world. The seven states of the northeast host large swathes of dense, tall evergreen forests which are home to a large variety of mammals and birds. Assam, the largest state in the northeast, has some of the last remaining lowland rainforests of India. These astoundingly tall Hollong (Dipterocarpus retusus) tree-dominated rainforests of Assam situated south of Brahmaputra, host seven species of primates. Among these primates, the most unique is the Western Hoolock Gibbon, the only non-human ape in India.

The Western Hoolock Gibbon, an exclusively arboreal primate is a charismatic entity of these rainforests. With long slender arms and hook-like grip, they easily navigate through the high canopies of the forests. The smooth swinging movement across the branches comes at the expense of evolutionarily reducing the thumb to a vestigial structure. They are known to jump large distances to move from one tree to another with ease. These abilities help them to forage and disperse efficiently in the forest.

They live in very small families comprising males, females and their young ones. Being monogamous, the gibbon pairs declare and defend their territories through intricate songs and calls that reverberate through the forest. Their territories may comprise many fruiting trees as their diet largely depends on them. Many times such fruiting trees are far from each other, which eventually pushes gibbons to have large territories.

Unfortunately, these rainforests have drastically reduced over the past century due to human actions, and whatever forests remain, are fragmented or isolated. One such habitat island is the Hoollongapar Wildlife Sanctuary. A haven for primates, it holds an increasing population of the Western Hoolock Gibbon. Although the sanctuary provides safety to these species, the impacts of linear infrastructure pose challenges for the species inside the sanctuary. A 1.6 Km long railway line cuts through the sanctuary dividing it into two parts. This critical and active railway line acts as a barrier for the species to travel, often posing threats to their life.

In many places, such fragmentation and habitat degradation has created isolated pockets of gibbon populations. Such populations are often forced to use the human modified landscapes and interact with humans. In Barekuri village of Tinsukia district of Assam, twenty-four gibbons reside in such situation. Here, these gibbons are loved by the local community as the gibbons have a special place in their culture. This love for the species has invoked conservation efforts such as plantation drives to restore the forests to improve connectivity among the forest patches. But this love and proximity have also started provisioning the gibbons with unnatural foods, which puts the gibbons at the risk of contracting diseases and even spreading some of these to humans

Although the intentions for conservation exist, only a clear understanding of the species’ requirements and behaviour can ensure sustainable ways to do it. The biggest threat for gibbons today is the severe reduction of their habitats and issues with dispersal due to fragmentation of habitat. With engagement from local communities and scientific conservation planning, we can attempt to protect this unique primate.

The Habitats Trust and Trippintoe productions present the story of these Western Hoolock Gibbons and the people who strive to protect them through an episode in their docuseries “Wild You Were Sleeping”. Hoping to elicit empathy and awareness among the general public, the series tries to bring people closer to the nature around them. Catch the episode on the Western Hoolock Gibbons here.