The endangered Western Hoolock Gibbons, the only ape of India, are under threat with cases of local extinction already observed in fragmented forest patches in the northeast region, a primatologist said here on Wednesday.

Habitat loss due to encroachment, unregulated resource extraction, infrastructure development, tea plantations, shifting cultivation, hunting, and wildlife trafficking are threats to these primates, he said.

'There has been a steady decline in the population of Western Hoolock Gibbons with cases of local extinction observed in fragmented forest patches of the northeastern region in India,' primatologist Dilip Chetry said after returning from Antananarivo in Madagascar, where the 30th Congress of the International Primatological Society (IPS) was held recently.