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.
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These snakes eat small rodents like mice and voles, but will sometimes eat frogs and other snakes.
This species is venomous, but because of the snake’s elusive and shy behavior, people rarely are bitten by them.
Eastern massasaugas use shallow wetlands and surrounding upland areas to forage, breed, shelter and hibernate.
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.
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.
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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