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Are there rattlesnakes in Michigan?

Last checked November 3, 2026 against official sources.

On this page
  1. The answer
  2. More official answers
  3. Which ones
  4. Sources

Yes.

Only the Eastern Massasauga, a state and federally threatened species of Lower Peninsula wetlands and Bois Blanc and Mackinac islands.

Michigan Department of Natural Resources: “Michigan contains a core population of eastern massasaugas, which live in specific wetlands in the Lower Peninsula as well as on Bois Blanc and Mackinac islands in Lake Huron.” Source

How we answer questions

Michigan

Think you have seen one in Michigan? Keep your distance and contact the Michigan Department of Natural Resources (DNR), Wildlife Division.

  • Are there venomous snakes in Michigan?

    Yes. One: the Eastern Massasauga Rattlesnake is Michigan's only venomous snake. The other 17 snake species are harmless to humans. Michigan Department of Natural Resources

  • Are there venomous snakes in the upper peninsula?

    No. DNR: massasaugas are not in the Upper Peninsula, so there are no venomous snakes on the mainland. DNR also places them on Bois Blanc and Mackinac islands in Lake Huron. Michigan Department of Natural Resources

  • Are there water moccasins (cottonmouths) in Michigan?

    No. The DNR says the massasauga is the only venomous species found in Michigan; MSU Extension says northern water snakes are often mistaken for 'water moccasins'. Michigan Department of Natural Resources

On Michigan's official list

Eastern Massasauga Rattlesnake
Photo: User:Rstanton13 · CC BY-SA 4.0 · Wikimedia Commons · resized

Eastern Massasauga Rattlesnake

Sistrurus catenatus

Venomous per Michigan Department of Natural Resources

Danger to people
“The eastern massasauga rattlesnake is Michigan’s only venomous native snake. The snake’s bite is painful but extremely unlikely to be fatal.” Michigan Department of Natural Resources
Size
Usually 18 to 30 inches long (New York DEC: 18 to 40 inches, average 27.5). The western massasauga in Arizona reaches only about 22 inches.
How to recognize it
  • A segmented rattle (a single button in newborns) and vertical, catlike pupils. In Michigan it is the only snake with both.
  • Nine large plates on top of the head (the timber rattlesnake has many small scales there)
  • A heat-sensing pit on each side of the head between the eye and nostril; the head is flat and much wider than the neck
Where in Michigan
The Eastern Massasauga occurs throughout the Lower Peninsula and on Bois Blanc Island, Mackinac County … Michigan State University Extension
Conservation
state threatened; federally threatened
What the sources say

Venom: “Eastern massasauga rattlesnake (VENOMOUS).” (Michigan Department of Natural Resources)

Range: The Eastern Massasauga occurs throughout the Lower Peninsula and on Bois Blanc Island, Mackinac County. There are no records for this or any other venomous snake in the Upper Peninsula.

Habitat: The Eastern Massasauga, the only venomous species of snake in Michigan, inhabits marshes and swamps, though they often wander into upland meadows and woods in summer. (Michigan State University Extension)

Full Eastern Massasauga Rattlesnake guide

All snakes in the state: Michigan snakes.

When snakes are seen in Michigan

985 records (GBIF, CC0 and CC BY).

Other questions about Michigan

Sources

  1. DNR urges public to give eastern massasauga rattlesnake its space. Michigan Department of Natural Resources. August 6, 2026; checked November 3, 2026.
    Quoted passages (2)
    “Michigan contains a core population of eastern massasaugas, which live in specific wetlands in the Lower Peninsula as well as on Bois Blanc and Mackinac islands in Lake Huron.”
    “The eastern massasauga rattlesnake is Michigan’s only venomous native snake. The snake’s bite is painful but extremely unlikely to be fatal.”
  2. Michigan Snakes: A Field Guide and Pocket Reference (MSU Extension Bulletin E-2000). Michigan State University Extension (MSU Library archive). Revised 1999; checked November 3, 2026.
  3. Snakes (Michigan DNR species page). Michigan Department of Natural Resources. archived copy, captured March 12, 2026; checked November 3, 2026. Archived copy.
    Quoted passages (2)
    “Eastern massasauga rattlesnake (VENOMOUS).”
    “Seventeen of these species are nonvenomous, with the only venomous snake being the eastern massasauga rattlesnake.”
  4. Eastern massasauga rattlesnake (Michigan DNR species page). Michigan Department of Natural Resources. archived copy, captured August 8, 2026; checked November 3, 2026. Archived copy.
    Quoted passages (2)
    “It is the only Michigan snake with segmented rattles on the end of its tail and elliptical, ("catlike") vertical pupils in the eyes.”
    “Massasaugas are found throughout the Lower Peninsula, but not in the Upper Peninsula (thus there are no venomous snakes on the Upper Peninsula mainland.)”
  5. When encountering Michigan's snakes, best to leave them be. Michigan Department of Natural Resources. May 31, 2016; checked November 3, 2026.
    Quoted passages (1)
    “…the eastern massasauga rattlesnake, the only venomous species found in Michigan”
  6. GBIF.org occurrence records, human observations licensed CC0 1.0 or CC BY 4.0 only, accessed November 3, 2026. The datasets behind these counts are listed on our Sources page.