Are there rattlesnakes in Wisconsin?
Western diamondback rattlesnake: Only as rare records. GBIF holds 3 open records of the western diamondback rattlesnake from Wisconsin, but there is no known population.
Timber rattlesnake: Yes. The timber rattlesnake lives in Wisconsin. Open records come from 7 counties.
Eastern massasauga: Yes. The eastern massasauga lives in Wisconsin. Open records come from 7 counties.

Where in Wisconsin
- None recorded
- 1 species
- 2
- 3 to 4
- 5 or more
Rattlesnakes across the US
- Lives here
- Rare records
- Gone
- Not here
How to recognize them
Timber rattlesnake Crotalus horridus
- Dark V- or chevron-shaped bands across the back
- Black tail ending in a rattle
- Yellow, tan or dark phases; some are almost black
Dangerous. Usually calm and slow to strike, but a bite is a medical emergency.
Eastern massasauga Sistrurus catenatus
- Gray or brown with large dark blotches down the back
- Small rattle
- Nine large plates on top of the head
Medically significant. Listed as threatened under the federal Endangered Species Act. Bites are rare and need medical care.
Often mistaken for rattlesnakes
- Rattlesnake vs Gopher Snake Gopher snake: harmless, lives in Wisconsin
- Eastern Diamondback vs Timber Rattlesnake Timber rattlesnake: dangerous, lives in Wisconsin
- Timber Rattlesnake vs Copperhead Copperhead: medically significant
- Western Diamondback vs Mojave Rattlesnake Mojave rattlesnake: dangerous
- Pygmy Rattlesnake vs Hognose Snake Eastern hognose snake: harmless, lives in Wisconsin
Questions
Are there rattlesnakes in Wisconsin?
Yes. 2 species live in Wisconsin: Timber rattlesnake and Eastern massasauga.
What do rattlesnakes look like?
Dark diamonds with pale yellow edges down the back. Two pale diagonal stripes on each side of the face. Thick body and a rattle on the tail.