How to Identify the Short-Tailed Mamushi (Identification Guide)

Key identifying features

The Short-Tailed Mamushi is a small to medium pit viper distinguished from its close relatives by a notably short, thick tail relative to overall body length. It has the classic pit viper build: a heavy, muscular body that tapers abruptly, a large triangular head clearly wider than the neck, and vertically elliptical pupils visible in good light. A deep heat-sensing pit sits between each eye and nostril, one of the most reliable field marks for any pit viper.

Coloration & pattern

Base coloration ranges from grayish-brown to reddish-tan, overlaid with a series of dark, rounded or oval blotches running down the back. These blotches are often edged with a lighter halo, giving a somewhat scalloped appearance, and may alternate slightly from side to side rather than aligning perfectly. The belly is pale gray to cream, often speckled with darker flecks. Older individuals sometimes appear duller and more uniformly brown as the pattern fades with age.

Head, eyes & scales

The head is broad and distinctly triangular, covered in small irregular scales rather than large plates, typical of pit vipers. A dark stripe frequently runs from behind the eye toward the jaw. The eyes have vertical, cat-like pupils. Body scales are keeled, giving the skin a rough, dull rather than glossy texture.

Size & body shape

Adults are generally modest in size, typically under two feet in length, with a stocky, thick-bodied build. The tail is proportionally shorter than in related mamushi species, ending relatively abruptly rather than tapering to a long, thin point.

Range & habitat where you'll see it

This species favors rocky hillsides, grassy slopes, and forest edges at moderate elevations, often basking on sun-warmed rocks or hiding beneath surface debris. It is most active during warmer months and tends to avoid deep forest interiors in favor of more open, exposed terrain.

How to tell it apart from look-alikes

Compared to other mamushi species, the short, blunt tail is the most useful distinguishing feature in hand or in close photographs. Overall blotch shape and head triangularity separate it from non-venomous colubrids, which lack heat pits and have round pupils. Its stockier build and duller coloration help distinguish it from more slender, brightly patterned pit vipers found in the same region.