Hollongapar Gibbon Sanctuary

Hollongapar Gibbon Sanctuary (formerly Gibbon Wildlife Sanctuary) is a 20.98-square-kilometer wildlife sanctuary near Mariani, Jorhat District, Assam, at 100 meters elevation. It is India's only protected area named after its primary resident, the Western Hoolock Gibbon (Hoolock hoolock), and boasts the highest density of gibbons in Northeast India.

The Call of the Canopy: A Morning in Hollongapar

Step into the sanctuary at 6:00 AM, and you are greeted by a heavy, cool mist rising from the surrounding tea estates, immediately swallowed by the dark, dense foliage of the evergreen forest. As the first rays of sunlight pierce the multi-layered canopy of giant Hollong trees, a rising, haunting duet of whooping calls echoes through the canopy. This is the morning song of the Western Hoolock Gibbon family, marking their territory with vocalizations that can be heard up to two kilometers away.

Walking silently along the leaf-strewn forest floor, the scent of damp moss and wild cardamom filling the air, you look up to see a family of black and golden-brown gibbons effortlessly swinging through the branches. Unlike most wildlife sanctuaries where you are separated from the wilderness by the metal body of a jeep, Hollongapar invites you to walk its trails on foot, creating a deeply intimate encounter with one of India's most endangered primates.

Natural Ecology and the Forest Island

Characterized as the Assam Valley tropical wet evergreen forest type, Hollongapar is a vital ecological sanctuary. The forest structure is defined by its distinct layers. The emergent layer is dominated by the majestic Hollong tree (Dipterocarpus macrocarpus), which reaches heights of over 40 meters, while the middle canopy is filled with Nahor (Mesua ferrea), known for its hard wood and fragrant white blossoms. The undergrowth is a dense tangle of bamboo, cane, ferns, and wild lianas.

However, this rich ecosystem is also one of the most fragmented in Northeast India. Hollongapar is a "forest island," entirely encircled by tea estates like Meleng and human settlements. This isolation restricts the migration of its residents and presents long-term genetic challenges. According to the Wildlife Institute of India, maintaining the canopy continuity is absolutely critical for the survival of the strictly arboreal Hoolock Gibbons, who refuse to descend to the ground to travel.

A Sanctuary of Seven Primates

While the Western Hoolock Gibbon is the star of Hollongapar, the sanctuary is exceptionally unique for hosting seven distinct primate species in an area of just 20.98 square kilometers.

Alongside the Hoolock Gibbon, you can spot the Capped Langur (Trachypithecus pileatus) with its pale golden coat and distinct dark face cap, and the Stump-tailed Macaque (Macaca arctoides), recognizable by its short tail and bright pinkish face. The canopy is also home to the Pig-tailed Macaque (Macaca leonina), the Assamese Macaque (Macaca assamensis), and the common Rhesus Macaque (Macaca mulatta). Deep in the shadows of the night, the Bengal Slow Loris (Nycticebus bengalensis), India's only venomous primate, hunts silently among the branches, though it is rarely seen by daytime visitors.

Wildlife and Birding in the Undergrowth

Beyond its primates, Hollongapar is a paradise for birdwatchers, with over 200 bird species recorded in its boundaries. The multi-layered canopy provides nesting sites for the Great Indian Hornbill, the Wreathed Hornbill, the Collared Falconet, and the colourful Green-billed Malkoha.

Mammals like the barking deer, wild boar, jungle cat, and leopards also roam the undergrowth. A herd of 40 to 50 wild elephants regularly traverses the sanctuary. These elephants use Hollongapar as a temporary refuge and foraging ground, often leading to dramatic encounters when they cross into the neighboring tea gardens.

Exploring Hollongapar on foot

Unlike Kaziranga National Park, where visitors view wildlife from jeeps or elephant backs, Hollongapar is explored strictly on foot. A walking safari offers a quiet, slow-paced immersion into the wet evergreen jungle.

Under the mandatory escort of armed forest guards and experienced local guides, visitors follow one of three primary nature trails. The popular 3-kilometer railway loop takes you past the sanctuary's most active Hoolock Gibbon family territories. For those seeking a deeper trek, the 6-kilometer primary forest trail penetrates deeper into the evergreen interior, offering a higher chance of spotting capped langurs and rare hornbills. Leeches (Haemadipsa sylvestris) are extremely active on the damp forest floor; wearing thick leech socks is mandatory for a comfortable walk, especially from May to October.

The Divided Forest: Lakhimpur-Mariani Railway Line

The most significant conservation challenge in Hollongapar is the Lakhimpur-Mariani broad gauge railway line, which bisects the sanctuary, cutting off a 2.8-hectare fragment from the main forest body.

Because Hoolock Gibbons are strictly arboreal and will not walk on the ground, this railway track created a complete genetic barrier for the gibbons in the isolated fragment. To address this, the Assam Forest Department, in collaboration with conservation groups, installed artificial canopy bridges made of thick ropes over the tracks, successfully encouraging the gibbons to cross. The railway line also poses a regular threat to the sanctuary's wild elephants, who must cross the tracks to forage, leading to strict speed limits for trains passing through this critical corridor.

What NOT to Expect

Hollongapar is not a destination for rapid-fire wildlife spotting or open-country safaris. You will not see rhinos, and while leopards are present, they are virtually never spotted. Sighting gibbons requires patient walking and looking straight up into the high canopy, which can be physically tiring. The sanctuary is small, and you will occasionally hear the distant sounds of tea garden workers or trains passing through the center of the forest. The Bengal Slow Loris is strictly nocturnal, so do not expect to see one during standard daylight visiting hours.

When Is the Best Time to Visit Hollongapar?

The best season to visit is from November to March when the weather is cool and dry. Daytime temperatures average a pleasant 22°C to 25°C, while mornings can drop to 10°C, requiring a light jacket.

Avoid the monsoon months from June to September when the sanctuary receives over 2,500 mm of rain. During this period, the walking trails become extremely muddy and slippery, and terrestrial leeches emerge in massive numbers, making trekking highly uncomfortable.

Getting There and Itinerary Context

Hollongapar Gibbon Sanctuary is located 19 kilometers from Jorhat town (45 minutes by road) and 5 kilometers from Mariani Junction railway station. Mariani is a major railway hub with overnight trains connecting to Guwahati. Jorhat Rowriah Airport (JRH), located 25 kilometers away, offers daily regional flights.

Hollongapar is typically visited as a day trip from Jorhat, or as a scenic stopover when traveling between Kaziranga destination guide and Majuli Island. It is featured as a key primate experience in the 9-Day Assam & Meghalaya Wildlife Tour.