Eastern Massasauga Rattlesnake

Sistrurus catenatus catenatus

Massasauga rattlesnake

The eastern massasauga rattlesnake (Sistrurus catenatus catenatus) is a unique and fascinating part of Michigan's natural heritage. It is Michigan's only venomous snake, and one of only two rattlesnake species that occur in the Great Lakes region. It is a small- to medium-sized snake, with adult lengths averaging 2 to 3 feet. The eastern massasauga is primarily associated with wetland habitats but some populations also utilize adjacent upland habitats for parts of its life history. Although it's venomous, the massasauga is a timid snake. It prefers to avoid detection by hiding under vegetation, woody debris or other cover or remaining motionless and relying on its cryptic coloration. When it is disturbed or encountered in open habitat, the massasauga prefers to move to a more hidden location. Most people in Michigan may never even see a massasauga in the wild because of its secretive behavior. The massasauga also appears to have strong site fidelity, often returning to the same hibernation site or area each year. Studies to date also have found that massasaugas were not be able to survive the winter when moved to a new area outside their home range presumably because they were not able to find suitable hibernation sites.

Massasauga rattlesnake habitat

Michigan appears to be the last stronghold for this species with more massasauga populations currently than any other state or province within the species' range. Thus, the eastern massasauga's long-term viability in Michigan has important implications for this species' persistence rangewide. However, Michigan's massasauga population also has declined. The primary reasons for the massasauga's decline in Michigan and rangewide are habitat loss and fragmentation, human persecution or indiscriminant killing, and illegal collection.

Massasauga rattlesnake Photo by Steve Crescenzo

The purpose of this website is to help increase public knowledge and awareness of the eastern massasauga in Michigan by providing comprehensive information about this often misunderstood species as well as additional resources and contacts where further assistance can be obtained. This website also is designed to help facilitate and coordinate ongoing massasauga education and outreach efforts in the state by providing educational resources and a forum for disseminating consistent, accurate and up-to-date information about the massasauga. The ultimate goal of this website is to provide people with the knowledge and skills they need to make an informed decision about how they can safely co-exist with the eastern massasauga. We hope that this effort will help keep Michigan's citizens safe and help ensure that the eastern massasauga remains a vital part of Michigan's rich natural heritage for future generations.


State Status:
Special Concern
Federal Status:
Candidate Species

An assessment of the eastern massasauga's status in Michigan was conducted from 1994 to 1996. At that time, about 200 occurrences of the eastern massasauga had been documented from 50 counties in the state. The status assessment reported that the massasauga population in Michigan had declined with about 20-25% of the known occurrences in the state considered to be extirpated and another 38% of the known occurrences considered to be vulnerable or declining. Only 20% of the known occurrences in the state were considered to be secure, and the status of about 18% of the occurrences was unknown. Recent surveys conducted from 2001-2004 have documented eastern massasaugas from at least 79 sites in 27 counties. However, the current status and long-term viability of most of these populations remain unknown.

As a result of its decline in the state, the eastern massasauga has been designated a species of special concern. Special concern status indicates that the species is sufficiently rare or uncommon or has undergone a serious decline in the state such that it could become threatened in the foreseeable future.

In Michigan, as a species of special concern, the eastern massasauga is protected under a special Director of Natural Resources' order, Director's Order No. DFI-166.98, Regulations on the Take of Reptiles and Amphibians (in accordance with sections 1c(1) and (2), chapter II, Act. 165 of the Public Acts of 1929, as amended, being sections 302.1c(1) and 302.1c(2) of the Michigan Compiled Laws). The Director's Order states that it is unlawful to kill, take, trap, possess, buy, sell, offer to buy or sell, barter, or attempt to take, trap, possess or barter an eastern massasauga from the wild except as authorized under a permit from the director. The Michigan Department of Natural Resources' Fisheries Division can be contacted for more information about this regulation and associated permits.

MichiganSpecial Concern
(Likely Extirpated)
New YorkEndangered

The eastern massasauga was once common across its range but has declined dramatically since the mid-1970's, according to a 1998 eastern massasauga status assessment conducted by the U.S. Fish and Wildlife Service. Massasaugas now mainly occur in disjunct, isolated populations and have been afforded some level of legal protection in every state or province within its range (see right). As a result, the eastern massasauga was listed as a federal candidate species by the U.S. Fish and Wildlife Service in 1999. Federal candidate species are plants and animals for which there is sufficient information on their biological status and threats to propose them as endangered or threatened under the Endangered Species Act, but for which development of a listing regulation is precluded by other higher priority listing activities.

Michigan Distribution

Historically, eastern massasaugas were found throughout the Lower Peninsula and on Bois Blanc Island. Within the last decade, eastern massasaugas have been reported from about 150 sites in 50 counties. These sightings appear to cluster in several regions across the Lower Peninsula, indicating areas where massasaugas may be concentrated. These include Oakland, Livingston, Jackson and Washtenaw counties in southeast Michigan, Allegan, Barry and Kalamazoo counties in southwest Michigan, and Iosco, Crawford and Kalkaska counties in northern Michigan. Nearly one- third of the historical occurrences in the state has not been reconfirmed in the past ten years. Massasaugas have not been reported from Branch, Ingham, Shiawassee, Macomb, Huron, Clare, Oscoda, Montmorency and Emmet counties since prior to 1980 (some since the early 1900's). It is important to note, however, that a statewide, systematic field survey for this species has not been conducted. Also, massasaugas are highly cryptic and difficult to observe in its natural habitat. Therefore, massasaugas may still be present in areas that lack recent, as well as historical, records.

Facebook link