EASTERN MASSASAUGA RATTLESNAKE

Identification

The Eastern Massasauga Rattlesnake is a small, thick-bodied rattlesnake. Adults are typically 20 to 25 inches long. Its back is usually light grey to light brown, with one row of large dark brown spots running down the center, and rows of small spots to either side. These spots join together on the head to create stripes, and on the tail to create rings. The ventral The underside or bellysurface, is dark black with flecks of lighter color mixed in. The massasauga can also be black or nearly so (melanistic) in some geographic locations. Specific features that indicate that it is a poisonous snake include the presence of a triangular shaped head, rattle segments at the tip of the tail, vertical pupils, and heat sensing pits just between the eyes and the nostrils. Juvenile massasaugas look similar to adults, except they have a green or yellow color at the very tip of the tail. The youngest juveniles also only have one rattle segment, called a “button.” The massasauga is also referred to as the swamp rattler.

Distribution and Status
The massasauga is found in the province of Ontario, Canada, and across the Midwest and eastward into the following ten states: New York, Pennsylvania, Ohio, Michigan, Indiana, Illinois, Wisconsin, Minnesota, Iowa, and Missouri. MAP. In Michigan, the massasauga is listed as a species of Special Concern. In all other states, and in Ontario, the snake is listed as Endangered. It is also currently a candidate species for listing by the US Fish and Wildlife Service as Threatened. Click HERE for state by state status descriptions.

Ecology

In the Midwest, massasaugas are almost always associated with shallow wetland systems such as fens, wet prairies, and other areas often dominated by sedges or grasses. In addition, these habitats also have at least a partially open tree and shrub canopy, which affords excellent areas for basking. The massasauga's diet consists almost entirely of small rodents, though juveniles also eat small snakes, such as young garter snakes. Massasaugas are ovoviviparous. Gravid (pregnant) females move to more exposed, often drier areas during pregnancy to incubate their young. Pregnant females have also been known to take advantage of objects which permit an increased exposure to sunlight, such as building foundations and even "beached" boats! Wetland habitat is particularly important for the overwinter survival of massasaugas as they often use crayfish burrows and holes underneath vegetation to hibernate. The snakes are generally below the water table during hibernation. Because of their low metabolic rates, they do not suffocate, and the presence of water actually keeps them from freezing! Another interesting fact is that massasaugas often return to the same area to hibernate, and sometimes even to the same burrow year after year.

Habitat loss and degradation are the main reasons for the decline of this species. Wetland draining and filling and fragmentation of upland and wetland habitats are all significant contributors to this problem. Persecution by humans has had an additional negative impact to massasauga populations. Although the bite of a massasauga can be a serious matter, the Eastern Massasauga Rattlesnake, along with other poisonous snake species in the Midwest, has received some bad publicity. Contrary to popular belief, the massasauga is not aggressive and they do not bite unless stepped on or picked up. In fact, bites from massasaugas are extremely rare. Management efforts for the massasauga need to include plans for conservation and restoration of habitats, as well as plans for the continuing education of the public about this species. The Habitat Management Guidelines for Amphibians and Reptiles of the Midwest provides some excellent thoughts and recommendations on "herp" friendly management techniques.

Resources
Johnson et al. 2000. The Eastern Massasauga Rattlesnake: A Handbook for Land Managers. U.S. Fish and Wildlife Service, Fort Snelling, Minnesota.

Szymanski, J. 1998. Status assessment for the Eastern Massasauga Rattlesnake (Sistrurus c. catenatus). US Fish and Wildlife Service, Fort Snelling, Minnesota.