Plants and Animals

Sistrurus catenatus Eastern massasauga

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Jim H. Harding
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John T. Legge
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Lisa Hallock
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Lisa Hallock
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Lisa Hallock
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Jim H. Harding
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John T. Legge
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John T. Legge
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Lisa Hallock
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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

US Status: LT - Listed Threatened
State Status: T - Threatened (legally protected)
Global Rank: G3 - Vulnerable
State Rank: S3 - Vulnerable


CountyNumber of OccurrencesYear Last Observed
Alcona 5 2020
Allegan 20 2020
Alpena 6 2010
Antrim 3 2006
Arenac 2 1986
Barry 19 2023
Benzie 1 1976
Berrien 9 2021
Branch 2 2010
Calhoun 9 2019
Cass 9 2021
Cheboygan 3 2017
Clare 3 2020
Clinton 4 2006
Crawford 9 2023
Eaton 3 1980
Emmet 2 2022
Genesee 5 2020
Grand Traverse 2 2006
Hillsdale 3 2020
Huron 3 1908
Ingham 2 2001
Ionia 1 1960
Iosco 15 2020
Jackson 23 2022
Kalamazoo 19 2022
Kalkaska 8 2023
Kent 2 2006
Lake 7 2023
Lapeer 3 2021
Lenawee 4 2022
Livingston 23 2021
Mackinac 1 2020
Macomb 1 2021
Manistee 4 2022
Mason 6 2023
Missaukee 2 2020
Montcalm 2 2005
Montmorency 6 2019
Muskegon 6 2005
Newaygo 4 2023
Oakland 33 2023
Oceana 1 2016
Oscoda 1 1964
Presque Isle 7 2019
Roscommon 3 2020
Saginaw 4 2009
Shiawassee 1 1928
St. Joseph 4 2019
Van Buren 12 2021
Washtenaw 17 2023
Wayne 1 1858

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: BogCoastal plain marshDry northern forestDry sand prairieDry southern forestDry-mesic northern forestDry-mesic prairieDry-mesic southern forestEmergent marshFloodplain forestIntermittent wetlandMesic northern forestMesic prairieMesic southern forestNorthern fenNorthern hardwood swampNorthern shrub thicketNorthern wet meadowOak barrensOak-pine barrensPine barrensPoor conifer swampPrairie fenRich conifer swampSouthern hardwood swampSouthern shrub-carrSouthern wet meadowWet prairieWet-mesic sand prairie

Snag/cavity needed in: Hardwood-conifer swampMesic sand prairieRich tamarack swamp

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.

Management Recommendations

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.

Visual encounter survey during spring emergence

Survey Period: From first week of April to second week of September

Time of Day: Daytime
Cloud Cover: Overcast
Air Temperature: Above 60 degrees
Wind: Light Breeze


Survey References

  • Casper, G.S., T.G. Anton, R.W. Hay, A.T. Holycross, R.S. King, B.A. Kingsbury, D. Mauger, C. Parent, C.A. Phillips, A. Resetar, and R.A. Seigel. 2001. Recommended standard survey protocol for the eastern massasauga, Sistrurus catenatus catenatus. U.S. Fish and Wildlife Service, Fort Snelling, MN. 9 pp.
  • Karns, D.R. 1986. Field Herpetology: Methods for the Study of Amphibians and Reptiles in Minnesota. Occ. Pap. No. 18. J.F. Bell Museum of Natural History, University of Minnesota, Minneapolis.

Technical References

  • Hallock, L. A. 1990. Master's Thesis: Habitat utilization, diet and behavior of the eastern massasauga (S. c. catenatus) in southern Michigan. Dept. of Zool., Michigan State Univ., E. Lansing, MI. 31 pp. (S. c. catenatus) in southern Michigan. Dept. of Zool., Michigan State Univ., E. Lansing, MI. 31 pp.
  • Harding, J.H. 1997.Amphibians and Reptiles of the Great Lakes Region. The University of Michigan Press, Ann Arbor. 378pp.
  • Johnson et al. 2000. The Eastern Massasauga Rattlesnake: A Handbook for Land Managers. U.S. Fish and Wildlife Service, Ft. Snelling, MN 55111-4056 52 pp. + appx.
  • Johnson, B. and V. Menzies, eds. 1993. Proceedings of the International Symposium and Workshop on the Conservation of the Eastern Massasauga Rattlesnake Sistrurus catenatus catenatus, May 8-9, 1992. Metro Toronto Zoo, Ontario, Canada. 136 pp.
  • Johnson, G. 1995. Spatial ecology, habitat preference, and habitat management of the eastern massasauga, Sistrurus c. catenatus, in a New York weakly-minerotrophic peatland. Dissertation. SUNY, College of Environmental Science and Forestry, Syracuse, NY. 222pp.
  • Lee, Y. and J. T. Legge. 2000. Special animal abstract for Sistrurus catenatus catenatus (eastern massasauga). Michigan Natural Features Inventory, Lansing, MI. 4 pp.
  • Reinert, H. K. and W. R. Kodrich. 1982. Movements and habitat utilization by the massasauga, S. c. catenatus. J. Herpetol. 16: 162-171.
  • Seigel, R. A. 1986. Ecology and conservation of an endangered rattlesnake, S. catenatus, in Missouri, U.S.A. Biol. Conserv. 35: 333-346.
  • Szymanski, J. A. 1998. Status assessment for the eastern massasauga (Sistrurus c. catenatus). U.S. Fish and Wildlife Service, Fort Snelling, MN. 19 pp + apps.

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