Prairie Rattlesnake
VenomousCrotalus viridis · also called western rattlesnake, great plains rattlesnake
The prairie rattlesnake is the rattlesnake of the Great Plains and the intermountain west, often found around prairie dog towns and rocky outcrops. Its blotches are oval rather than diamond-shaped, and its overall tone is greener than the desert species further south.
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.
Quick facts
- Venom
- Medically significant venom requiring emergency treatment. Watch your footing around rock piles and burrow entrances, and keep dogs close in prairie habitat.
- Adult length
- 24–45 inches (61–114 cm)
- Markings
- Rounded or oval dark blotches with pale edges on a greenish-grey, olive or light brown ground. The blotches become crossbands towards the tail.
- Habitat
- grassland, rocky, desert, farmland
- Family
- pit viper
- Range
- 14 US states
How to identify a prairie rattlesnake
- Oval blotches with light borders, not sharp diamonds.
- Distinctly greenish or olive cast to the ground colour in many populations.
- Rattle present, with a narrow neck behind a clearly wider head.
- Frequently found near rodent burrows and rock outcrops.
What it does when it sees you
Will rattle and retreat if given room. Dens communally in winter, so late autumn and early spring encounters near a den site can involve several snakes at once.
What the prairie rattlesnake is confused with
One test settles each of these.
Bullsnakes hiss and vibrate their tails convincingly but have no rattle, a round pupil, and a narrow head barely wider than the neck.