Order Squamata ; Suborder Serpentes
In Sri Lanka, the family Viperidae is represented by two species of highly venomous true vipers and five species of moderately venomous pit vipers. All members of this family have comparatively large heads and stout, rather short bodies. The Green pit viper and the three Hump-nosed vipers have a special organ called the loreal pit in-between the nostril and the eye in either side of the head. It is sensitive to IR (Infrared) radiation, thus allows the snake to.
locate warm-blooded prey. The Russell's viper is a highly venomous snake and is known to contain the longest venom fangs of any Sri Lankan snake. The Saw-scaled viper is mainly confined to the coastal areas of the Northern, North-western & Eastern dry zone and can produce sound by scale abrasion. The Green pit viper is endemic to the country and the wet zone and dry zone specimens shows a remarkable difference in the colour pattern, where the dry zone specimens are much dull in colour with less amount of black markings. The Hump-nosed vipers are considered to be moderately venomous, but severe envenoming is possible, thus are potentially lethal! These small snakes (Hump-nosed vipers) account for the highest percentage of snake bites in the country.