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Contact information
For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
For information on Wisconsin's rare invertebrates, contact:
Jay Watson
Conservation Biologist

Eastern Massasauga (Sistrurus catenatus)



Eastern Massasauga (Sistrurus catenatus) is a State Endangered Species and a Federally Threatened Species. This rattlesnake is strongly associated with floodplain habitats along medium to large rivers, especially near river confluences, where they primarily occupy open canopy wetlands, such as sedge meadows, fresh wet meadows, shrub-carrs, and adjacent upland prairies, floodplain forests, and old fields. Overwintering usually occurs in terrestrial crayfish burrows or rotted out root channels in open canopy wetlands, shrub-carrs, and lowland hardwood forests. Massasaugas begin to emerge in spring, usually in early April, from overwintering habitats. They can remain active until mid-November, depending on air temperatures. This species breeds primarily in August and females give birth in late July or August the following year.

For management activities with the potential to impact this species, please refer to the Eastern Massasauga Land Management Guidance document [PDF].

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Eastern Massasauga (Sistrurus catenatus). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Sistrurus catenatus in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusEND
Federal Status in WisconsinLT
State RankS1
Global RankG3
Tracked by NHIY

Species guidance

Eastern Massasauga (Sistrurus catenatus) has very few known occurrences in the state and is of the highest priority for conservation; we encourage you to consult with your District Ecologist or an NHI Zoologist for specific recommendations for your site.

Eastern Massasauga Land Management Guidance document [PDF]



Eastern Massasauga

Population declines of the eastern massasauga rattlesnake are due to habitat loss and human persecution. A few populations persist in the Central Sand Plains.

Photo by Rori Paloski, WDNR.

Eastern Massasauga

Close-up of eastern massasauga head.

Photo by Rori Paloski, WDNR.

Eastern Massasauga

Close-up of eastern massasauga rattle.

Photo by Rori Paloski, WDNR.

Eastern Massasauga

Photo © Dan Nedrelo.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Eastern Massasauga. Only natural communities for which Eastern Massasauga is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Ecological landscape associations

The table below lists the ecological landscape association scores for Eastern Massasauga. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Eastern Massasauga occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

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Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

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Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

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Last revised: Thursday, October 08, 2020