Sistrurus catenatus
Eastern massasauga
Image of Sistrurus catenatus

Photo by Terrence M. Cox 

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Key Characteristics

The Eastern Massasauga is a small to medium-sized (average 18-30 in/46-76 cm), thick-bodied, gray, gray-brown or brown snake with a distinctive color pattern of dark brown rectangular or saddle-shaped blotches down the back and two or three additional rows of dark spots along the sides of the body. The underside of the snake is either solid black or black with some light mottling. The tail has alternating dark and light bands and a segmented rattle at the end. It also has a triangular-shaped head (i.e., widens at the back of the head and narrows at the neck), vertical slit-shaped pupils, and large, heat-sensing pits or openings between the nostrils and the eyes. Newborn massasaugas range in length from 7-10 in (18-25 cm) and have a single button or rattle at the end of their tails.

Status and Rank

  • State Status: SC
  • US Status: LT
  • State Rank: S3
  • Global Rank: G3


County NameNumber of OccurrencesYear Last Observed
Grand Traverse22006
Presque Isle62008
St. Joseph32015
Van Buren122016
Distribution map for Sistrurus catenatus

Updated 5/15/2018. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Eastern Massasaugas have been found in a variety of wetland habitats. Populations in southern Michigan are typically associated with open wetlands, particularly prairie fens, while those in northern Michigan are known from open wetlands and lowland coniferous forests, such as cedar swamps. Some populations of Eastern Massasaugas also utilize open uplands and/or forest openings for foraging, basking, gestation and parturition (i.e., giving birth to young). Massasaugas usually hibernate below the frost line in crayfish or small mammal burrows, tree root networks or rock crevices in or along the edge of wetlands or in upland areas with presumably high water tables. Massasauga habitats generally appear to be characterized by the following: (1) open, sunny areas intermixed with shaded areas, presumably for thermoregulation; (2) presence of the water table near the surface for hibernation; and (3) variable elevations between adjoining lowland and upland habitats.

Specific Habitat Needs

Downed woody debris needed in Emergent marsh, Northern wet meadow, Southern wet meadow, Intermittent wetland, Coastal plain marsh, Wet prairie, Wet-mesic sand prairie, Prairie fen, Northern fen, Bog, Poor conifer swamp, Rich conifer swamp, Northern hardwood swamp, Southern hardwood swamp, Floodplain forest, Northern shrub thicket, Southern shrub-carr, Mesic southern forest, Dry-mesic southern forest, Dry southern forest, Mesic northern forest, Dry-mesic northern forest, Dry northern forest, Oak barrens, Oak-pine barrens, Pine barrens, Mesic prairie, Dry-mesic prairie, Dry sand prairie Snag/cavity needed in Rich tamarack swamp, Hardwood-conifer swamp, Mesic sand prairie

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.


Protection of extant populations and suitable wetland and adjacent upland habitats is crucial for successful conservation of the Eastern Massasauga. Maintaining or restoring open habitat conditions is critical for this species. Fragmentation of suitable wetland-upland habitat complexes by roads or other barriers should be avoided or minimized. Land management practices such as timber harvesting, mowing, disking or prescribed burning should be conducted in such a manner so as to minimize the potential for adverse impacts to massasaugas (e.g., conducting management activities during the snakes’ inactive season (November through early March) or on days when snakes are less likely to be active on the surface during the active season). Protecting suitable hibernation sites also is critical. Hydrological alterations such as drawdowns should be conducted prior to or after hibernation to reduce the potential for causing winter mortality due to desiccation or freezing. Sudden and/or permanent increases or decreases in water levels during the active season also can cause adverse impacts. Education and outreach efforts to raise public awareness and understanding of the Eastern Massasauga also are critical for conserving this species. Any suspected illegal collection of Eastern Massasaugas should be reported to local authorities. Massasaugas that need to be moved or translocated should be relocated to suitable habitat as close to where snakes were found and ideally within the snake's home range and within the same wetland complex.

Active Period

Active from first week of April to fourth week of October

Breeding from second week of July to fourth week of August

Parturition from first week of August to second week of September

Survey Methods

Massasaugas typically are active between April and late October, and can be seen anytime during the active period. However, the best times to survey for this species are during spring emergence (i.e., April-mid-June) and during the mating, gestation and birthing period in mid- to late summer (i.e., late July, August and early September) for gravid females and young-of-the-year. Another survey window for this species is during fall ingress when snakes are moving to and congregating around hibernacula. Visual encounter surveys for this species consist of walking through suitable habitat and looking for snakes basking, foraging, traveling or resting under cover, particularly along the edge of open wetlands and uplands and near shrub, woody debris or other vegetative cover or cover objects. Massasauga observations should be documented with photographs and/or verified by a species expert.

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Sep 23, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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