In a distressing event that has raised alarm among conservationists, an endangered hoolock gibbon was electrocuted on a railway line those traverses one of Assam’s biologically significant forests. This incident underscores the critical threats that the electrified railway poses to wildlife, particularly to tree-dwelling species such as hoolock gibbons. The recent electrification of the railway line, executed without adequate protective measures, has exacerbated the risks to these animals. Forest officials confirmed that the deceased was an adult male gibbon found in the Hollongapar Gibbon Wildlife Sanctuary, located near Mariani in Jorhat district. Arboreal species like gibbons typically avoid descending to the ground to evade predators and human activity, yet the railway line has fragmented the forest canopy, compelling them to traverse hazardous areas. As a consequence, gibbon families residing on either side of the railway — particularly the four to five groups in the smaller Compartment I — now find themselves isolated from each other.
The hoolock gibbon, which is India’s sole ape species, is afforded the highest legal protections under Schedule I of the Wildlife (Protection) Act of 1972. Despite numerous appeals from conservation experts advocating for the rerouting of a 1.65-kilometer section of the railway outside the sanctuary, authorities have proceeded with electrification, raising serious concerns regarding the long-term survival of the species. Organizations such as the Wildlife Institute of India (WII) have proposed the installation of artificial canopy bridges at strategic points to enable arboreal animals to cross the railway safely. Nonetheless, many experts contend that relocating the short railway segment entirely outside the sanctuary represents the most effective and sustainable solution. Primatologist Dr. Dilip Chetry emphasized that the railway line has effectively transformed the sanctuary into a “forest island,” isolating it from adjacent habitats, which notably affects gibbons reliant on a continuous forest canopy. This fragmentation also diminishes genetic exchange between gibbon groups, exacerbating their risk of decline.
Previous efforts to establish artificial canopy bridges have faltered, as prior designs failed to accommodate the unique brachiation movement characteristic of gibbons. The WII had recommended the construction of seven appropriately designed bridges, but experts warn that any future expansion of the railway could render these mitigation strategies ineffective. Spanning merely 20.98 square kilometers, the Hollon apar Gibbon Wildlife Sanctuary exhibits the highest richness of primate species in Assam, hosting approximately 125 hoolock gibbons organized into 26 groups.