Eastern Massasauga

Eastern Massasauga (Sistrurus catenatus catenatus)

Eastern massasauga./Dan Kennedy

General: Also known as the “swamp rattler,” the eastern massasauga is a thick-bodied, small rattlesnake whose range extends from southern Ontario and western Pennsylvania west through Ohio, Michigan, and several other Midwestern states. Massasauguas live in marshes and wet meadows bordering old fields. They prey on crayfish and frogs in wetlands, and rodents and insects in uplands. They prefer upland sites with plenty of dense, low vegetation, a low to moderate density of shrubs, and few trees. The openness of such habitats provides areas where massasaugas can bask and thermoregulate; nearby dense understory vegetation offers food and protective cover. During winter, massasauguas hibernate in wet soils, often in crayfish burrows 6 to 24 inches below the ground.

Status: The eastern massasauga is considered threatened, endangered, or a Species of Greatest Conservation Need in all 10 states within its range. The U.S. Fish and Wildlife Service has listed it as threatened under the Endangered Species Act. (Threatened species are animals that are likely to become endangered in the foreseeable future.) Factors that have caused the massasauga’s population to dwindle include the loss and degrading of wetland habitats, the gradual succession of old abandoned fields into mature forest, and important wetland and upland habitats being destroyed or fragmented by roads and development.

How to Help Eastern Massasaugas: Evidence exists that eastern massasaugas benefit from habitat management activities that give rise to young forest and old-field habitats, and that reduce tree canopy cover overhead. Because individual snakes can be hurt or killed by mowing and burning, such management activities must always be undertaken in the winter, while massasaugas are hibernating. Many massasauga populations are on public land and privately owned natural areas. The U.S. Fish and Wildlife Service is working with willing land managers to carry out practices that help and do not harm massasaugas and their habitats.

Both public and private landowners can make young forest habitat. The Young Forest Guide explains how.

Click on the map at left to see a larger image.

For more detailed information on the eastern massasauga, including references to scientific papers, download Under Cover: Wildlife of Shrublands and Young Forest. This publication can also be purchased from the Wildlife Management Institute.

To view a U.S. Fish and Wildlife Service fact sheet on the eastern massasauga, click on the file attachment below.

Visit a habitat demonstration area within this species' range to increase your chances of seeing this and other wildlife that use young forest.