Endangered Species
Midwest Region



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Eastern massasauga


Eastern Massasauga (Sistrurus catenatus)

Status: Threatened

The U.S. Fish and Wildlife Service listed the eastern massasauga rattlesnake (Sistrurus catenatus) as a threatened species under the Endangered Species Act. We also determined that designating critical habitat for the eastern massasauga is not prudent. The final rule to list the eastern massasauga as threatened publishes in the Federal Register on Sept. 30, 2016 - a public inspection version is available on Sept. 29. 


The eastern massasauga is a small, thick-bodied rattlesnake that lives in shallow wetlands and adjacent uplands in portions of Illinois, Indiana, Iowa, Michigan, Minnesota, New York, Ohio, Pennsylvania, Wisconsin, and Ontario. The species, a candidate for listing since 1999, has been declining over the past few decades due to loss and fragmentation of its wetland habitat. Nearly 40 percent of the historical populations are now extirpated and an additional 15 percent are of uncertain status.  Of those known remaining populations, most are experiencing ongoing threats, meaning additional population losses are anticipated in the future.

Eastern massasaugaPhoto courtesy of Joe Crowley

Eastern Massasauga

Status: Proposed as Threatened; 2015


Habitat: Open to forested wetlands and adjacent upland areas


Lead Region: 3


Region 3 Lead Office: Chicago, Illinois Field Office


Range: Illinois, Indiana, Iowa, Michigan, Minnesota, New York, Ohio, Pennsylvania, Wisconsin, and Ontario



from the Michigan DNR


From the Michigan DNR Natural Features Inventory


About Massasaugas


Identification and Look-Alikes


Life History and Ecology


Safety Tips and Snakebite Treatment


Report an Observation in Michigan



News Release


Final Rule (Federal Register) Adobe PDF Icon




Fact Sheet


Species Status Assessment (117-page PDF Adobe PDF Icon; 2.4MB)

This report summarizes the results of an assessment of the eastern massasauga's overall viability. The assessment begins with a description of the snake’s ecological requirements for survival and reproduction as they relate to its overall viability. We generally defined viability as the ability of the species to maintain self-sustaining populations over the long-term. Using the principles of resiliency, representation, and redundancy, we considered the species’ needs at the individual, population, and species scales. We also identified the beneficial and risk factors influencing the species’ viability. We considered the degree to which the species’ ecological needs are met both currently and as can be forecasted into the future, and assessed the consequences of any unmet needs as they relate to species viability.


Range wide Extinction Risk Modeling for the Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus) (66-page PDF Adobe PDF Icon; 2.3MB)


Life History and Ecology

Live and Let Live - Oakland County, Michigan Blog


Species Spotlight: Eastern Massasauga - USFWS Chicago Field Office


Eastern Massasauga - Michigan Society of Herpetologists


Species Survival Plan

AZA Species Survival Plan - A Species Survival Plan® is a collaborative science-based management program of the Association of Zoos and Aquariums (AZA).


Michigan is Main Focus of Eastern Massasauga Rattlesnake Survival Plan


Lincoln Park Zoo Recovery Efforts


Conservation and Research

Managing for Massasaugas - Edward Lowe Foundation | Land Stewardship. 4-page PDF. 2012


Long-term Research on Rattlesnake Life History Will Help Managers Plan Habitat Restoration August 7, 2012


Species Action Plan - Pennsylvania Fish and Boat Commission (PDF). June 2011


Learning to Live with the Eastern Massasauga Rattlesnake: Expanding Outreach and Education in Southern Michigan Dec. 31, 2009. 171-page PDF


Spotlight Species Action Plan October 2009. 9-Page PDF


Restoring Southeast Michigan’s High Diversity Landscapes Through Collaborative Stewardship – Hillsdale, Jackson, Lenawee, Oakland, and Washtenaw Counties, Michigan. Private Stewardship Grant (May 2007):


Reforestation and Wetland Restoration for Permanent Native Habitat in the St. Joseph River Watershed – Hillsdale County, Michigan; Defiance and Williams Counties, Ohio; Allen, Dekalb, and Noble Counties, Indiana Private Stewardship Grant. May 2007


Response to Habitat Management by the Eastern Massasauga (Sistrurus catenatus) at Carlyle Lake, lllinois S6 Grant Project. 2006


Molecular Diversity among Massasauga Rattlesnakes: Nuclear Intron Analyses S6 Grant Project 2006


Rome State Nature Preserve Candidate Conservation Agreement with Assurances Ashtabula County, Ohio. August 2006


Final Environmental Assessment for Eastern Massasauga Candidate Conservation Agreements in the Midwest. July 26, 2005


Survey and Management Guidances

A Handbook for Land Managers (PDF 1.2 MB)


Recommended Standard Survey Protocol





Midwest Endangered Species Home


Last updated: October 4, 2016