Eastern Massasauga

The eastern massasauga (Sistrurus catenatus) is a federally threatened rattlesnake. It is one of only three venomous snakes in Pennsylvania. They are brown snakes with black or brown blotches, which can grow up to three feet long. Massasaugas have rattles, but they are seldom heard because their rattles are small and quiet and only used on rare occasions. Pennsylvania is the eastern edge of their range. In 2013, a survey was conducted to determine their population, and they were only found in two counties in western Pennsylvania. In the spring, fall, and winter, they are found in wetlands and wet grasslands. They spend the summer in nearby upland forests. Massasaugas spend the winter hibernating alone in crayfish burrows or burrows made by other animals.

These snakes are ambush predators that rely on their venom—a cytotoxin— to kill their prey from internal bleeding. There are few recorded instances of massasaugas biting humans, but they are venomous. If bitten, a person should immediately seek medical attention. Mature snakes eat mainly small rodents like mice, squirrels, and shrews. Young snakes mainly eat amphibians and invertebrates.

Massasaugas breed in late-July and early-August. Females store sperm until the following spring when they release it to fertilize their eggs. Females carry fertilized eggs for three months, and then give birth to live young. When females are ready to give birth, they find an abandoned animal burrow or brush pile and give birth to 5-25 hatchlings. Females leave the birthplace within hours of giving birth, leaving hatchlings to begin life on their own. Snakes begin to reproduce at three to four years old.

The largest threat to massasaugas is habit loss. Many of the wetlands, wet meadows, and prairies have been turned into human settlement and farmland. Massasaugas rely on these areas for wintering habitat, and without this habitat they cannot survive. The upland forests that have not been developed are now being managed for older forests. While older forests are good for timber, they support few small mammals, making them less suitable habitat for massasaugas. Forests and wetlands are also being invaded by invasive plant species; this reduces prey populations. Massasaugas are secretive snakes who prefer to hide from people, but when people find massasaugas, they tend to kill these beautiful snakes out of fear, despite there being few instances of massasaugas biting humans.