How to Identify the Eastern Massasauga (Identification Guide)

Key identifying features

The eastern massasauga (Sistrurus catenatus) is a small, thick-bodied rattlesnake found in scattered wetland and prairie habitats across the Great Lakes region and parts of the midwestern United States. It is recognized by its gray to grayish-brown body marked with rows of large, dark brown or blackish blotches, a small rattle that produces a faint buzzing sound, and nine large plate-like scales on top of the head, unlike most other rattlesnakes which have many small scales there.

Coloration & pattern

The dorsal ground color is typically gray, tan, or light brown, patterned with a row of large, rounded to oval dark brown or black blotches running down the back, with smaller alternating blotches along the sides. This creates a strongly contrasting, somewhat checkered appearance. The belly is usually black or heavily marked with dark blotches on a lighter background.

Head, eyes & scales

The head is broad and triangular, distinct from the neck, with vertically elliptical pupils typical of pit vipers. A key identifying feature is the presence of nine large, symmetrical scales on top of the head, a trait shared with other massasaugas and pygmy rattlesnakes but differing from most larger rattlesnake species, which have small, fragmented head scales. Dorsal body scales are keeled.

Size & body shape

This is a small rattlesnake, with adults typically reaching only 45 to 75 cm in length. The body is relatively thick for its length, and the rattle, while present, is small and produces a quiet, insect-like buzz rather than the loud rattle associated with larger rattlesnake species.

Range & habitat where you'll see it

The eastern massasauga is found in scattered populations across the Great Lakes region, from parts of the northeastern and midwestern United States into southern Ontario, favoring wetland edges, wet prairies, bogs, and adjacent upland habitats. It often basks near open, sunny patches close to water or damp ground.

How to tell it apart from look-alikes

The combination of nine large head scales, a small overall size, and a strongly blotched gray-brown pattern distinguishes the massasauga from larger rattlesnakes, which typically have small, numerous scales on the head. Its association with wetland and prairie habitats, rather than dry rocky terrain, also helps narrow identification within its range.