Eastern Massasauga Rattlesnake
Sistrurus catenatus catenatus
Eastern Massasauga Rattlesnakes Description
What do I do if I see a Massasauga?
Eastern Massasauga Rattlesnake links
Eastern Massasauga
Did you know?
Eastern Massasauga Rattlesnakes are known by many names, Some people call them, Massasauga Rattlers, Black Massasauga Rattlers, Michigan Rattlers, Swamp Rattlers and many other names.

The word Massasauga (mass-a-saw'-ga) is said to mean “great river mouth” in the Chippewa language describing the swampland surrounding a river delta where the snakes can be found. Eastern Massasauga Rattlesnakes are known by their scientific name as Sistrurus Catenatus. Equipped with heat sensing pit-organs, venom and a rattle, they are Michigan 's only poisonous snake.

Eastern Massasauga Rattlesnakes are pit vipers, being equipped with heat-sensing pit organs between the eye and nostril on either side of their heads. These pits lead to a pair of extremely sensitive infrared organs that serve as a set of primitive eyes that can operate even when the snakes eyes and ears cannot. We have much to learn about this evolutionary technology.

Eastern Massasauga Rattlesnakes have a pair of long hollow fangs that they can inject venom into their prey. When the fangs are not in use they fold against the roof of the mouth enclosed in a membranous sheath. During a strike an Eastern Massasauga Rattlesnake will eject the fangs at the last possible moment, each fang can be engaged simultaneously or independently. The strike is very fast and can work as more of a stab in a defensive strike. The venom of the Eastern Massasauga Rattlesnake uses specialized digestive enzymes that disrupt the cardiovascular system. Eastern Massasauga Rattlesnake venom is generally regarded as less dangerous to humans because they inject less venom than larger rattlers. However, all venomous snakebites should be considered dangerous and medical attention sought.

Eastern Massasauga Rattlesnakes use their very fast strike to incapacitate small animals like mice so they can consume the animal without having to fight it to the death. One bite the animal dies the snake moves in to swallow it's prey whole. The venom also has some digestive properties that help the snake digest it's victim.
Eastern Massasauga Rattlesnakes in Michigan


Special Concern, it is protected by the State of Michigan and is a candidate for federal listing.


Entire Lower Peninsula of Michigan,. Although once common, populations may be declining due to loss of wetland habitats and human harassment.


During spring, Massasaugas use open shallow wetlands or shrub swamps. They can be found in crayfish towers or small animal burrows which are adjacent to drier upland open shrub forest sites. During summer, Massasaugas move upland to drier areas. Look for them "sunning" in open fields, grassy meadows or farmed sites.


Sluggish, slow moving snake. It may strike if threatened.


Eastern Massasauga rattlesnakes eat small mammals, amphibians and insects. The Massasaugas are eaten by eagles, herons and some mammals.


  • Massasaugas have thick bodies with colors that range from gray, grayish brown or brown. Its back has large dark brown blotches with smaller lighter brown patches on its sides. Young Massasaugas are similarly marked with brighter coloration.
  • This snake has a wide triangular head and eyes with slit shaped pupils.
  • Adults can be 18" to 30" in length.
  • Young Massasaugas have small yellow buttons or "rattles" at the tip of their tail. Adult "rattles" are grayish yellow, like pieces of corn kernels, on top of dark rings.
  • Snakes may bite to protect themselves.

What do I do if I see a Massasauga?

  • Keep your distance and observe it from a distance.
  • Do not kill the snake.
  • Use caution.
  • Remember it deserves a safe living space.
  • Do not pick it up.
  • Keep all pets away.
  • If you live or recreate in areas that are historic habitats of the massasauga, study their habits.
  • Learn what to do if you or a pet is bitten.
    • If a pet, notify your veterinarian and immediately take pet to a veterinarian for treatment.
    • You are bitten, contact 911 or contact your medical care provider or emergency room for further direction.
  • Report your Eastern Massasauga Rattlesnake observations in Michigan.

Remember, not all snakes are poisonous. Additional information is available on Michigan's snakes .

Links to more information about Eastern Massasauga Rattlesnakes:

Visit the Michigan Department of Natural Resources informative page
on the Eastern Massasauga Rattlesnake

Center for Reptile and Amphibian Conservation and Management's page
for Eastern Massasauga Rattlesnakes

Wisconson DNR page for Eastern Massasauga Rattlesnakes

US Fish and Wildlife Service - Endangered Species - Fact Sheet: Questions and Answers about the Conservation of the Eastern Massasauga Rattle Snake

Eastern Massasauga (Swamp Rattlesnake) (Sistrurus catenatus)

Canadian Museum of Natural History- Massasauga Rattlesnake

Sistrurus catenatus- Eastern Massasauga Rattlensakes on Wikipedia

Ojibway Narute Center - Windsor - Eastern Massasauga Rattlesnake

US Fish and Wildlife Service Information sheet on Massasauga Rattlesnakes

Did you know?:

The Eastern Massasauga Rattlesnake is Michigan 's only poisonous snake

Rattlesnakes make up the genus Crotalus, the name from Greek word krotalon, meaning rattle.

Detroit 's Belle Island was once home to so many Massasauga Rattlesnakes; it earned the name ‘ Snake Island '.

Eastern Massasauga rattlesnakes are shy and avoid humans when they can.

An Eastern Massasauga Rattlesnake bite is often a very painful experience and should always be taken seriously, even though it is not necessarily fatal.

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