How to Identify Wirot's Pit Viper (Identification Guide)
A guide to recognizing Wirot's Pit Viper by its triangular head, heat-sensing pits, keeled scales, and green coloration found in Southeast Asian forests.
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Key identifying features
Wirot's Pit Viper (Trimeresurus wiroti) is a venomous pit viper native to Southeast Asia, identifiable by its broad triangular head, heat-sensing facial pits, vertically elliptical pupils, and rough keeled scales, consistent with the arboreal green pit vipers of the region.
Coloration & pattern
The body is typically green to yellowish-green, often with a faint bluish or turquoise tint, and may show a thin white or pale lateral stripe running along the lower side of the body, particularly prominent in males of similar related species. Faint darker speckling can also be present, aiding camouflage among leaves and vines in its forest habitat.
Head, eyes & scales
The head is broad, triangular, and clearly set apart from the neck, characteristic of pit vipers, with a heat-sensing pit located between each eye and nostril used to detect warm-blooded prey in low light. The eyes have vertical, cat-like pupils, and the scales are keeled, giving the body a rough, matte texture.
Size & body shape
This is a small to medium pit viper, generally reaching 50–80 cm (20–31 inches), with a moderately slender body suited to arboreal life, and a prehensile tail tip that helps the snake grip branches and vines while climbing.
Range & habitat where you'll see it
Wirot's Pit Viper is found in parts of mainland Southeast Asia, inhabiting forested regions, often at moderate elevations, where it lives an arboreal and largely nocturnal existence, typically found coiled on low branches, shrubs, or vegetation near forest edges and streams.
How to tell it apart from look-alikes
The broad triangular head, heat-sensing pits, and vertical pupils distinguish this species from non-venomous green tree snakes that share a superficially similar green coloration but lack these venomous pit viper features. Differentiating Wirot's Pit Viper from other closely related green pit vipers in the same region, such as various other Trimeresurus species, often depends on subtle differences in lateral striping, precise coloration, and geographic range, making locality an important clue alongside general pit viper morphology.
Frequently asked questions
Is Wirot's Pit Viper venomous?
Yes, it is a venomous pit viper found in Southeast Asia.
How can I tell it apart from a non-venomous green tree snake?
Look for the broad triangular head, heat-sensing facial pits, and vertical pupils, which non-venomous tree snakes lack.
Where is Wirot's Pit Viper found?
It occurs in forested regions of mainland Southeast Asia, often at moderate elevations.
Is this species active during the day or night?
It is largely nocturnal, typically found coiled on low branches or vegetation after dark.
What color is Wirot's Pit Viper?
It is typically green to yellowish-green, sometimes with a bluish tint and a pale lateral stripe.