How to Identify the Two-striped Forest Pit Viper (Identification Guide)

Key identifying features

The two-striped forest pit viper is a venomous, arboreal species of the Amazon Basin in South America, best identified by two pale, often yellowish or greenish-white stripes running along the lower sides of a predominantly green body, combined with the broad triangular head and heat-sensing pits typical of pit vipers. This lateral striping against a green background is the key feature distinguishing it from other forest pit vipers in the region.

Coloration & pattern

The dorsal background color is usually bright to emerald green, sometimes with a bluish or yellowish tinge, providing excellent camouflage among rainforest foliage. Two narrow pale stripes, typically pale yellow, cream, or greenish-white, run along each side of the body, usually positioned low on the flanks near the boundary with the belly. The belly is generally a paler green or yellowish tone, and the tail tip is sometimes reddish or rusty in color.

Head, eyes & scales

The head is broad, flattened, and strongly triangular, clearly wider than the neck, characteristic of pit vipers. Heat-sensing pits are present between the eye and nostril on each side, and the pupils are vertically elliptical. Scales are keeled, giving the body a slightly rough texture despite its otherwise smooth green appearance.

Size & body shape

Adults typically reach around 60 to 100 centimeters in length, making this a relatively slender, modest-sized pit viper. The body is slim and suited to climbing, and the tail is prehensile, aiding movement through branches and foliage in its arboreal habitat.

Range & habitat where you'll see it

This species inhabits humid lowland rainforest across the Amazon Basin and neighboring regions of northern South America. It is primarily arboreal, resting coiled among vegetation during the day and becoming active at night to hunt small vertebrates in the trees and shrub layer.

How to tell it apart from look-alikes

The combination of the triangular head, vertical pupils, and keeled scales separates this species from harmless green colubrids, which have rounded heads and round pupils. The paired pale lateral stripes along a bright green body, together with the prehensile tail and arboreal habits, help distinguish it from other green pit vipers that may lack this distinctive striping. Careful observation of the flanks, where the stripes are most visible, is often the most reliable way to confirm this particular species.