Rattlesnake
Western Diamond-backed Rattlesnake
VenomousCrotalus atrox
2 photographs of the Western Diamond-backed Rattlesnake. © Mark Wilson.
The Western Diamond-backed Rattlesnake (Crotalus atrox) is a venomous snake in the Viperidae family, recorded in 3 countries.
If you are bitten
Rattlesnake bites are medically serious. Expect intense pain, rapid swelling, and bruising. Stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to an emergency room immediately. Do NOT apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call Poison Control at 1-800-222-1222 or 911 in the US, or your local emergency number. (Source: CDC.)
- Also called
- Rattlesnake
- Family
- Viperidae
- Size
- Typically 2–5 ft; some species exceed 6 ft.
- Habitat
- Deserts, rocky outcrops, grasslands, and woodland edges, depending on species.
- Behavior
- Ambush predators that buzz the tail as a warning; mostly active in warm months and often crepuscular in summer heat.
- Identify
- Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
- Danger
- high
About the Western Diamond-backed Rattlesnake
The western diamondback rattlesnake (Crotalus atrox) or western diamond-backed rattlesnake, is a rattlesnake species and member of the viper family, found in the southwestern United States and Mexico. Like all other rattlesnakes and all other vipers, it is venomous. It is likely responsible for the majority of snakebite fatalities in northern Mexico and the greatest number of snakebites in the U.S. No subspecies are currently recognized.
It lives in elevations from below sea level up to 6,500 feet (2,000 m). This species ranges throughout the Southwestern United States and northern half of Mexico. Currently, western diamondback rattlesnakes are not threatened or endangered.
Common names
Other common names for this species include western diamond-backed rattlesnake, adobe snake, Arizona diamond rattlesnake, coon tail, desert diamond-back, desert diamond rattlesnake, sand tail, fierce rattlesnake, spitting rattlesnake, buzz tail, Texan rattlesnake, Texas diamond-back, Texas bark and Texas rattler.
Description
Adults commonly grow to 120 cm (4 ft) in length. Specimens over 150 cm (5 ft) are infrequently encountered, while those over 180 cm (6 ft) are very rare, and the largest reported length considered to be reliable is 213 cm (7 ft). Males become much larger than females, although this difference in size does not occur until after they have reached sexual maturity. Rattlesnakes of this species considered medium-sized weigh up to 1.23 to 2.7 kg (3 to 6 lb), while very large specimens can reportedly weigh up to 6.7 kg (15 lb). Overall, it is likely the second largest-bodied species of rattlesnake, behind only its close cousin the eastern diamondback rattlesnake. It is also the second largest of North American venomous snakes (the bushmasters, which attain similar weights and greater total length, occur up as far as Nicaragua).
The color pattern generally consists of a khaki ground color, but it may also be pinkish or fallow, brick red, yellowish blonde, or white. This ground color is overlaid dorsally with a series of 23-45 (mean, 36) dorsal body blotches that are brown or a darker umber. The first of these may be a pair of short stripes that extend backwards to eventually merge. Some of the first few blotches on the back may be somewhat rectangular, but then become more hexagonal and eventually take on the distinctive diamond shape. The clarity of these markings is often blurred by small specks. The tail has two to eight (usually four to six) black bands separated by white or gray interspaces; this led to the nickname of "coontail", though other species (e.g., Mojave rattlesnake) have similarly banded tails. Its postocular stripe is gray or umber and extends diagonally from the lower edge of the eye across the side of the head. This stripe is usually bordered below by a white stripe running from the upper preocular scale down to the supralabial scales just below and behind the eye.
Adapted from Wikipedia, available under CC BY-SA.
Frequently asked: Western Diamond-backed Rattlesnake
- Is the Western Diamond-backed Rattlesnake venomous?
- Yes. The Western Diamond-backed Rattlesnake (Crotalus atrox) is venomous and belongs to the Viperidae family (rattlesnake). Its bite is considered high risk to people. Treat any bite as a medical emergency.
- Is the Western Diamond-backed Rattlesnake poisonous?
- Snakes are venomous, not poisonous. "Poisonous" means harmful to eat or touch; "venomous" means injecting toxins through a bite. The Western Diamond-backed Rattlesnake is venomous, delivering venom through a bite.
- Is the Western Diamond-backed Rattlesnake dangerous?
- Rattlesnake bites are medically serious. Expect intense pain, rapid swelling, and bruising. Stay calm, keep the bitten limb still and roughly level with the heart, remove rings and tight clothing, and get to an emergency room immediately. Do NOT apply a tourniquet, cut the wound, apply ice, or try to suck out venom. Call Poison Control at 1-800-222-1222 or 911 in the US, or your local emergency number. (Source: CDC.)
- Where does the Western Diamond-backed Rattlesnake live?
- The Western Diamond-backed Rattlesnake has verified records in 3 countries, including United States of America, Mexico, Canada. See the distribution section below for its full range.
- How do I identify the Western Diamond-backed Rattlesnake?
- Heavy body, broad triangular head, vertical (cat-like) pupils, and a segmented keratin rattle at the tail tip.
- How big does the Western Diamond-backed Rattlesnake get?
- Typically 2–5 ft; some species exceed 6 ft.
- What does the Western Diamond-backed Rattlesnake eat?
- A comprehensive study by Beavers (1976) on the prey of C. atrox in Texas showed, by weight, 94.8% of their prey consisted of small mammals. According to Pisani and Stephenson (1991), who conducted a study of the stomach contents of C. atrox in the fall and spring of Oklahoma, mammalian prey included prairie dogs (Cynomys ludovicianus), kangaroo rats (Dipodomys ordii), pocket gophers (Geomys bursarius and Cratogeomys castanops), voles (Microtus ochrogaster), woodrats (Neotoma floridana), pocket mice (Perognathus hispidus and P. flavescens), white-footed mice (Peromyscus leucopus and P.
- Why is it called the Western Diamond-backed Rattlesnake?
- Other common names for this species include western diamond-backed rattlesnake, adobe snake, Arizona diamond rattlesnake, coon tail, desert diamond-back, desert diamond rattlesnake, sand tail, fierce rattlesnake, spitting rattlesnake, buzz tail, Texan rattlesnake, Texas diamond-back, Texas bark and Texas rattler.
If you are bitten by the Western Diamond-backed Rattlesnake
Do
- Get away from the snake and stay calm. Most bites worsen when people panic or try again to handle the snake.
- Call 911 or Poison Control (1-800-222-1222) right away. Antivenom works best when given early.
- Note the time of the bite and, from a safe distance, the snake's color and pattern, a phone photo is enough. Do not chase it.
- Keep the bitten limb still and at roughly heart level. Sit or lie down and limit movement.
- Remove rings, watches, and tight clothing near the bite before swelling starts.
- Gently wash the bite with soap and water and cover it with a clean, dry dressing.
Do not
- Do not cut the wound or try to suck out the venom.
- Do not apply a tourniquet or ice.
- Do not drink alcohol or caffeine.
- Do not take aspirin or ibuprofen, they can worsen bleeding. Acetaminophen is safer for pain.
- Do not try to catch or kill the snake. A dead snake can still bite by reflex.
First-aid guidance adapted from the U.S. Centers for Disease Control and Prevention (CDC NIOSH), Venomous Snakes. Educational only; always follow the instructions of emergency responders.
Where it is found
Snakes it is confused with
Gopher SnakeHarmlessRattlesnakes are sometimes confused with harmless gophersnakes/bullsnakes; only rattlesnakes have a true segmented rattle and a facial pit.
Western Diamond-backed Rattlesnake vs Gopher Snake→
More Viperidae snakes
Western RattlesnakeCrotalus oreganus
Timber RattlesnakeCrotalus horridus
Prairie RattlesnakeCrotalus viridis
Red Diamond RattlesnakeCrotalus ruber
Mojave RattlesnakeCrotalus scutulatus
Western Black-tailed RattlesnakeCrotalus molossus
SidewinderCrotalus cerastes
Southwestern Speckled RattlesnakeCrotalus pyrrhus
Classification
How scientists group this snake, from the broadest category down to the exact species. Each step narrows to its closest relatives.
Keep learning
- Are Snakes Dangerous? The Real Risk, in PerspectiveMost snakes are harmless and avoid people. Here is the honest picture of snakebite risk worldwide and how to lower your own.
- Snakebite First Aid: What to Do (and What Never to Do)A clear, CDC-based guide to snakebite first aid: the steps that help, the popular myths that hurt, and how to tell a serious bite from a minor one.
- Venomous vs Nonvenomous: How to Tell the DifferenceThe folk rules for telling venomous snakes apart, where each one fails, and why location-based identification beats guessing by sight.
- What to Do If You Find a SnakeFound a snake at home or on a trail? Here is how to stay calm, give it space, identify it safely, and know when to call a professional.
Distribution from GBIF & iNaturalist. Venom status per CDC. Background: Wikipedia. Informational only. Never handle a snake to identify it.