Inside the Hollongapar Gibbon Reserve in Assam, a male Western Hoolock Gibbon was recorded confidently swinging across a specially built canopy bridge over the Lumding-Dibrugarh railway line, marking what scientists say is the first documented case anywhere of such a structure being used on active train tracks.
“This is the first confirmed case of a gibbon using such a structure in the reserve and the first documented case anywhere in the world of using a canopy bridge over a railway line,” said GV Gopi, a scientist at the Wildlife Institute in Dehradun in India, who headed the project.
He said five double rope bridges equipped with safety nets have been installed as a mitigation measure after the electrification of the Lumding-Dibrugarh railway line passing through the forest area. “The structures are designed to help arboreal species cross the railway track safely without descending to the ground, where they face the dangers of trains and predators,” he added.
Linear infrastructure such as railways and roads can fragment forest habitats, posing serious threats to wildlife living in the canopies, Gopi said, adding that the successful use of canopy bridges demonstrates how carefully planned mitigation measures can reduce these risks.
“Long-term conservation of gibbons will require careful infrastructure planning and selection of environmentally sensitive sites, along with restoring forest corridors to reconnect isolated populations,” he said.
Expressing his gratitude to the Assam Forest Department and partner institutions involved in designing, installing and monitoring the canopy bridges, he said, “Incidentally, it was also Endangered Species Day.”
The Western hoolock gibbon is the only species of monkey in India and belongs to the family Hylobatidae, which includes small monkeys or gibbons. It is classified as endangered on the International Union for Conservation of Nature (IUCN) Red List and is protected under Schedule I of the Wildlife Protection Act, 1972, giving it the highest level of legal protection in India.
This species is found only in the forests of northeastern India, especially in Assam, Arunachal Pradesh, Meghalaya and Nagaland, with small populations also found in Bangladesh and Myanmar. Their distribution is highly fragmented, which makes conservation efforts particularly difficult. It is completely arboreal, meaning it lives entirely in trees and relies on the continuous forest canopy for movement and survival.
