How to Identify the Hundred-Pace Viper (Identification Guide)

Key identifying features

The hundred-pace viper (Deinagkistrodon acutus) is identified by a series of large, dark triangular or diamond-shaped blotches along its back, a boldly patterned body, and a soft, pale-colored tail tip that contrasts with the rest of the body. It has an unusually long, upturned, pointed snout compared to most pit vipers.

Coloration & pattern

The body is typically light brown, tan, or reddish-brown with a row of large dark brown to black triangular markings pointing downward along each side, sometimes meeting at the spine to form diamond shapes. The belly is white or cream with dark blotches. The tail is noticeably pale, often whitish or yellowish, near the very tip.

Head, eyes & scales

The head is large, triangular, and clearly distinct from the neck, with a somewhat elongated and upturned snout unlike the blunter heads of many other pit vipers. Heat-sensing pits sit between the eye and nostril. Pupils are vertically elliptical. Body scales are strongly keeled, giving a rough texture.

Size & body shape

Adults commonly reach 1 to 1.5 meters (about 3 to 5 feet), with a heavy, thick body and a relatively short tail. The body shape is stout and robust rather than slender.

Range & habitat where you'll see it

This species occurs in southern China, Taiwan, and northern Vietnam, typically in hilly and mountainous forested terrain, often near streams, rocky slopes, and agricultural edges at low to moderate elevations.

How to tell it apart from look-alikes

The combination of the upturned pointed snout, large triangular side blotches, and pale tail tip separates the hundred-pace viper from other Asian pit vipers, which generally have blunter snouts and different blotch shapes. Its range in Taiwan and southern China also helps narrow identification.