How to Identify the Sri Lankan Hump-Nosed Pit Viper (Identification Guide)

Key identifying features

The Sri Lankan Hump-Nosed Pit Viper is a small, terrestrial pit viper endemic to Sri Lanka, closely related to other hump-nosed pit vipers of South Asia. Its most distinguishing feature is an upturned, somewhat pointed snout, combined with the classic pit viper traits of a broad triangular head, heat-sensing pits, and vertical pupils.

Coloration & pattern

The body pattern is cryptic, typically composed of brown, gray, or reddish-brown background coloration overlaid with darker, irregular blotches, triangles, or zigzag-like markings along the back. This patterning provides effective camouflage among leaf litter and forest floor debris. The belly is usually pale, often cream or light gray, sometimes with scattered dark speckling.

Head, eyes & scales

The snout is distinctly upturned or hump-shaped, a defining feature of this and closely related species, giving the face a somewhat pointed profile from the side. The head overall is broad and triangular, clearly wider than the neck, with a heat-sensing pit between each eye and nostril. The eyes show vertical pupils. Dorsal scales are strongly keeled, giving the body a rough, textured surface.

Size & body shape

This is a small pit viper, with adults typically measuring roughly 30 to 45 centimeters in total length. The body is relatively stout for its length, an adaptation suited to a terrestrial, leaf-litter-dwelling lifestyle rather than climbing.

Range & habitat where you'll see it

This species is endemic to Sri Lanka, where it inhabits forested areas, particularly in wet zone and hill country forests, often found among leaf litter, low vegetation, and forest floor debris rather than in trees. It is largely nocturnal and relies on camouflage, often remaining motionless when approached.

How to tell it apart from look-alikes

The upturned snout is the most reliable field mark distinguishing this species from most other pit vipers, though care should be taken since other closely related hump-nosed pit viper species occur in the wider South Asian region; endemic range within Sri Lanka is a useful additional clue for this particular species. Its muted, blotched, ground-colored patterning clearly separates it from bright green arboreal pit vipers found elsewhere on the island. The broad triangular head, vertical pupils, and heat-sensing facial pits confirm identification as a pit viper rather than a harmless terrestrial colubrid snake found in similar habitat.