FWS Focus

Overview

Characteristics
Overview

The eastern massasauga rattlesnake is a small pit viper that occurs in the northern midwest United States and Ontario, Canada. Originally believed to be a subspecies of western massasauga rattlesnake, genetic analyses have since demonstrated it to be a distinct species that was reclassified in 2011 as Sistrurus catenatus.

Eastern massasaugas were listed as threatened under the Endangered Species Act in 2016 due to significant reductions in populations primarily due to habitat loss. The historical range of the species included New York, western Pennsylvania, southeastern Ontario, Michigan, Ohio, Indiana, Illinois, Wisconsin, Minnesota, east central Missouri and eastern Iowa.

Scientific Name

Sistrurus catenatus
Common Name
Massasauga
Eastern Massasauga
Eastern Massasauga (=rattlesnake)
FWS Category
Reptiles
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Habitat

Characteristics
Habitat

Eastern massasaugas use shallow wetlands and surrounding upland areas to forage, breed, shelter and hibernate.

Characteristic category

Physical Characteristics

Characteristics
Size & Shape

Eastern massasaugas are thick-bodied, with a triangular-shaped head and vertical pupils. The most distinguishing feature of eastern massasauga rattlesnakes is a keratinized rattle at the end of the tail, which is used to ward off potential threats.

Color & Pattern

These snakes are most often gray or light brown, but can be black, with large light-edged chocolate brown to black blotches on the back and smaller blotches on the sides. Their cryptic coloration allows them to rely on its camouflage to avoid predators and capture prey.

Characteristic category

Food

Characteristics
Food

These snakes eat small rodents like mice and voles, but will sometimes eat frogs and other snakes.

Characteristic category

Behavior

Characteristics
Behavior

This species is venomous, but because of the snake’s elusive and shy behavior, people rarely are bitten by them.

Geography

Characteristics
Range

Currently, most of the remaining populations are concentrated in the center of the range, with the strongholds being in Michigan and Ontario, Canada. New York, Pennsylvania, Ohio, Indiana, Illinois, Wisconsin and Iowa still have some robust populations, but they become fewer in number and increase in geographic isolation towards the edges of the species range.

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