Western Diamondback Rattlesnake
VenomousCrotalus atrox · also called coontail rattler, Texas diamondback
The western diamondback accounts for more serious snakebites than any other species in the United States. It is abundant across the southwest, it is large, and it defends itself readily. The equal black-and-white tail rings separate it from the Mojave rattlesnake, which shares much of its range and has considerably more dangerous venom.
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
- Serious envenomation risk with a large venom yield. Emergency care and antivenom are required. Never attempt to kill one — a severed head can still reflexively bite for some time.
- Adult length
- 30–60 inches (76–152 cm)
- Markings
- Dusty diamonds with fuzzy, indistinct edges rather than crisp outlines. The tail carries alternating black and white rings of roughly equal width — the 'coontail' — immediately before the rattle.
- Habitat
- desert, grassland, rocky, suburban
- Family
- pit viper
- Range
- 7 US states
How to identify a western diamondback rattlesnake
- Black and white tail rings of roughly equal width just before the rattle.
- Diamonds have soft, blurred edges, as if the pattern were slightly out of focus.
- Pale diagonal face stripe meets the mouth line in front of the angle of the jaw.
- Often stands its ground with the head and neck raised in an S-coil.
What it does when it sees you
Readier to stand its ground and rattle than most rattlesnakes. It will hold a defensive coil rather than retreat, so back away rather than expecting it to leave.
What the western diamondback rattlesnake is confused with
One test settles each of these.
On a Mojave, the white tail rings are clearly wider than the black ones. On a western diamondback they are roughly equal.
Gopher snakes have no rattle, a round pupil, and blotches rather than diamonds — but they hiss loudly and vibrate the tail, which fools people constantly.