How to Identify McGregor's Pit Viper (Identification Guide)

Key identifying features

McGregor's Pit Viper is a distinctive arboreal pit viper known for a series of pale, often yellowish or whitish spots scattered across a green body, combined with the family's hallmark triangular head, vertical pupils, and heat-sensing facial pits.

Coloration & pattern

The base color is green to bluish-green, contrasted by scattered pale spots or blotches, often yellow, cream, or whitish, that stand out clearly against the darker green background. This spotted appearance is more pronounced than the faint speckling seen in some closely related species. The belly is pale green to yellowish, generally unmarked or lightly mottled.

Head, eyes & scales

The head is broad and triangular, clearly set off from the neck, with small scales. Eyes are large with vertical pupils, and a heat-sensing pit is present between each eye and nostril. Body scales are keeled, adding a slightly rough texture to the vivid green coloring.

Size & body shape

The body is slender, laterally compressed, and adapted for climbing, with a prehensile tail. Overall size is modest, typical of arboreal pit vipers in its genus and region.

Range & habitat where you'll see it

This species has a restricted distribution, generally associated with specific island or montane forest habitats, where it is found resting on low branches, shrubs, and vegetation in humid forest environments.

How to tell it apart from look-alikes

The combination of scattered pale spots against a green body is more conspicuous than the subtle speckling or faint banding found in many related green pit vipers, making pattern contrast a useful diagnostic feature. Its narrow geographic range further helps confirm identification when compared with similar-looking species from other islands or regions. The triangular head, vertical pupil, and heat pit distinguish it from harmless green tree snakes in the same habitat.