The Eastern Massasauga Rattlesnake is a small, venomous snake recently listed as threatened by the U.S. Fish and Wildlife Service. It persists in only a few locations in Illinois, Indiana, Iowa, Michigan, New York, Ohio, Pennsylvania, and Wisconsin. The Fish and Wildlife Service describes the Massasauga as “a small snake with a thick body, heart-shaped head and vertical pupils.” Adults can grow to be about two feet long. They occupy upland areas part of the year and wet marshy areas during winter months. They often hibernate in crayfish burrows. Their main prey is small rodents.