Is the massasauga venomous?

The massasauga is venomous. Venom is medically significant despite the snake's small size and requires hospital treatment. Legally protected across much of its range, so it should be left entirely alone.

How do you identify a massasauga?

Nine large plates on the crown of the head, like the pygmy rattlesnake and unlike the larger rattlesnakes. Dark blotches on grey, with three extra rows of small blotches along each flank.

Where do massasaugas live?

They are found in 16 US states, in habitats including wetland, grassland and farmland.

Massasauga

Venomous

Sistrurus catenatus · also called swamp rattler, black snapper

The massasauga is a small rattlesnake of wet prairies, fens and marsh edges. The eastern subspecies is federally threatened and has become genuinely rare, so an encounter is unusual and worth reporting to a state wildlife agency rather than acting on.

Before anything else

Back away and leave it alone. A snake that can see you leaving has no reason to bite. Most bites in the United States happen to people who picked up, cornered, or tried to kill a snake.
Never handle a snake to identify it. Every identification on this site can be made from a photo or from several feet away.
If someone is bitten, call emergency services now. Keep the limb still and below the heart, remove rings and watches, and go to hospital. Do not cut, suck, apply ice, or use a tourniquet — all of these make outcomes worse.
Do not try to catch the snake for identification. A photo from a distance is enough, and hospitals treat symptoms rather than species.

In the US, the Poison Help line is 1-800-222-1222. This site is a reference, not medical advice.

Venom: Venom is medically significant despite the snake's small size and requires hospital treatment. Legally protected across much of its range, so it should be left entirely alone.
Adult length: 18–30 inches (46–76 cm)
Markings: Large dark brown or black blotches on a grey ground, with three smaller rows of blotches along each side. A dark bar runs from each eye to the jaw.
Habitat: wetland, grassland, farmland
Family: pit viper
Range: 16 US states

How to identify a massasauga

Nine large plates on the crown of the head, like the pygmy rattlesnake and unlike the larger rattlesnakes.
Dark blotches on grey, with three extra rows of small blotches along each flank.
Small rattle producing a quiet buzz.
Associated with damp ground — wet meadows, fens, marsh borders.

What it does when it sees you

Shy and reluctant to rattle. Usually attempts to escape or freeze rather than confront.

What the massasauga is confused with

One test settles each of these.

Eastern hognose snake →

Hognose snakes have the upturned snout and no rattle, and flatten the neck dramatically.

Northern water snake →

Water snakes lack a rattle and have crossbands at the front of the body rather than separate blotches.

Where it lives

Arizona Colorado Illinois Indiana Iowa Kansas Michigan Missouri Nebraska New Mexico New York Ohio Oklahoma Pennsylvania Texas Wisconsin

Not sure it was a massasauga? Identify it step by step →