The endemic Sri Lankan keelback (Balanophis ceylonensis) is a snake largely restricted to rainforests of the island. Based on an 11-years field survey covering 83 field sites and rescued specimens, we present an autecology of B. ceylonensis. We recorded 32 individuals of B. ceylonensis at 25 field sites. All snakes were found in 10 – 1000 m altitude range within or in close proximity of rainforests. This snake associated with canopy-shaded forest floor with sufficient leaf litter and a numerous other natural cover objects, and were active mostly during dusk. Our study indicated that B. ceylonensis is a rare species with a patchy distribution within the wet zone of southwestern Sri Lanka, and can be considered a rainforest specialist. The reproductive season spanned from November to February as evident by observations on copulation. The snake laid eggs in clutches of 3 – 4 underneath woody debris or inside the forest floor. Given its rarity, patchy distribution, and estimated extend of occurrence and area of occupancy, and continuing degradation of rainforests, we assessed the conservation status of B. ceylonensis as Endangered.

Behaviour, biogeography, biology, distribution, habitat loss, Natricinae, rainforests, snakes.