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A Guide to the Amphibians
and Reptiles of California


Crotalus atrox - Western Diamond-backed Rattlesnake



Click on a picture for a larger view




Range in California: Red





Rattlesnake Sounds and Video



More pictures of C. atrox and habitat from the Southwest and Texas
observation link



Venomous and Potentially Dangerous!


Adult, Riverside county
© William Flaxington
Adult, Riverside county
© William Flaxington
Adult, Cochise County, Arizona
Adult, Riverside County
© Patrick Briggs
Adult, Riverside County
© Chad Lane
Adult, from just across the Colorado River in La Paz County, Arizona
Adult, Riverside County. Note that the rear light strip does not extend back to the corner of the mouth. © Patrick Briggs
Top of head showing several small scales between intraoculars.
© Patrick Briggs
Top of head showing several small scales between intraoculars.
Compare with the similar Northern Mohave Rattlesnake.
Adult in the typical Diamondback threatening defensive posture, Sierra County, New Mexico. Tail and Rattle
A Western Diamond-backed Rattlesnake eats a dove in Cochise County, Arizona. © Bob Herrmann
Habitat
Habitat, Imperial County Habitat, Imperial County Habitat, New River, Imperial County
Habitat, Imperial County Habitat, Riverside County
Habitat, Riverside County
 
Habitat, Imperial County California National Wildlife Refuge warning sign.

Click the picture to see more rattlesnake signs.
 
Short Videos and Sound



Several views of a Cochise County, Arizona Western Diamond-backed Rattlesnake rattling and taking a defensive pose with its head and tail elevated.
A Western Diamond-backed Rattlesnake rattles in a defensive pose in Sierra County, New Mexico.
  Listen to a Western Diamond-backed Rattlesnake rattle and hiss.

(This is the snake shown above in the first row, at the far right.)
 


Rattlesnakes are important members of the natural community. They will not attack, but if disturbed or cornered, they will defend themselves. Reasonable watchfulness should be sufficient to avoid snakebite. Give them distance and respect.



Description

Venomous
The venom of this snake is potentially dangerous to humans.
Size
Adults grow to 30-90 inches (76-229 cm). Most snakes encountered are from 1 to 4 feet in length.
Appearance
The largest rattlesnake in California, and in the West. Heavy-bodied, dangerously venomous, with a thin neck and a large triangular head. Pupils are elliptical. Scales are keeled. Sometimes 3, but usually 4 or more small scales occur on top of the head between the supraocular scales. (The Northern Mojave Rattlesnake has 2 large scales between the supraocular scales.)

The ground color and the intensity of the pattern are variable, often matching the habitat; grey, brown, olive, tan, or yellowish. Diamond-shaped blotches on the back are brown or black, with light edges. Broad black and white rings, fairly equal in width, circle a thick tail with a rattle, consisting of loose interlocking segments, at the end. A new rattle segment is added each time the skin is shed. Newborn snakes do not have a rattle - just a single button which does not make a sound. A light stripe extends from behind the eye diagonally to the upper lip in front of the corner of the mouth crossing over the lip. (The posterior light stripe of the Northern Mohave Rattlesnake extends back beyond the corner of the mouth and does not cross the lip.)

Similar to and easily confused with the Northern Mohave Rattlesnake, though there is little range overlap in California. Also similar to and easily confused with the Red Diamond Rattlesnake, but in California the ranges of these two snakes barely meet, and the Red Diamond Rattlesnake is typically light reddish brown or red in color.

A pit viper with pits on the sides of the head which sense heat. These heat sensors help the snake to locate prey by their warmth. Long, hollow, movable fangs connected to venom glands inject a very toxic venom which quickly immobilize the prey. The snake can control the amount of venom injected and the fangs are replaced if broken. Bites on humans are potentially deadly without immediate medical treatment. Even a dead snake can bite and inject venom if the jaws reflexively open when they are touched.

Behavior
Primarily nocturnal during periods of excessive daytime heat, but also active during daylight when the temperature is more moderate. Not active during cooler periods in Winter.

An ambush hunter, it typically sits near the trail of a mammal, waiting for it to pass by, then strikes at and releases the prey. The snake then follows the trail of the envenomated animal and swallows it whole.

When alarmed, a rattlesnake shakes its tail back and forth. The movement rubs the rattle segments together producing a buzzing sound which serves as a warning. When disturbed, in self-defense Western Diamond-backs will often aggressively hold their ground, raising the head high in a striking coil with the tail elevated and rattling, and hissing loudly. Juveniles are born with only a silent button at the end of the tail.
Diet
Eats small mammals, birds, lizards. Juveniles sometimes eat large insects and frogs.
Reproduction
Live-bearing. Males engage in ritual combat mostly during the breeding season to defend territory. Necks and forebodies are intertwined, with the stronger snake slamming the smaller one to the ground until the weaker snake leaves the area.
Range
Found in southeast California in Imperial, Riverside, and San Bernardino Counties. Ranges east to Arkansas and East Texas, and south through Arizona, New Mexico and Oklahoma into Mexico.
Habitat
Inhabits arid and semiarid areas including mountains, deserts, canyons and rocky vegetated foothills, generally less than 1000 ft. elevation (300 m).
Conservation Issues  (Conservation Status)
None.

Taxonomy
Family Viperidae Vipers
Genus Crotalus Rattlesnakes
Species


atrox Western Diamond-backed Rattlesnake
Original Description
Baird and Girard, 1853 - Cat. N. Amer. Rept., Pt. 1, p. 5

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Crotalus - Greek - krotalon - a rattle - refers to the rattle on the tail
atrox
- Latin - atrox dark, fierce, savage - referring to the sometimes savage disposition of this species

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Alternate Names
Western Diamondback Rattlesnake

Related or Similar Neighboring California Snakes
C. ruber - Red Diamond Rattlesnake
C. s. scutulatus - Northern Mohave Rattlesnake
C. c. laterorepens - Colorado Desert Sidewinder
C. c. cerastes - Mohave Desert Sidewinder
C. m. pyrrhus - Southwestern Speckled Rattlesnake
C. o. helleri - Southern Pacific Rattlesnake

More Information and References
Natureserve Explorer

California Dept. of Fish and Game

Living With Rattlesnakes

Tucson Herpetological Society: Living With Venomous Reptiles pdf

California Department of Fish and Game: Rattlesnakes in California

University of California: Rattlesnakes Management Guide

San Diego Natural History Museum: Rattlesnakes FAQ

Florida Museum of Natural History: How to Get Along with Snakes


Rattlesnake Bites

California Poison Control System: Rattlesnake Bites

University of Arizona: Rattlesnakes

Justin Schwartz' Rattlesnake Bite Story and Pictures

Sean Bush MD: Venom ER - When snakes strike!

When a Pet Gets Snake Bitten: The amazing story of Andy Cat, a cat who was bitten by a rattlesnake and survived, thanks to the smart actions of its owners.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Snakes of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Bartlett, R.D. , & Alan Tennant. Snakes of North America - Western Region. Gulf Publishing Co., 2000.

Brown, Philip R. A Field Guide to Snakes of California. Gulf Publishing Co., 1997.

Ernst, Carl H., Evelyn M. Ernst, & Robert M. Corker. Snakes of the United States and Canada. Smithsonian Institution Press, 2003.

Wright, Albert Hazen & Anna Allen Wright. Handbook of Snakes of the United States and Canada. Cornell University Press.

Ernst, Carl. H. Venomous Reptiles of North America. Smithsonian Institution Press, 1999.

Hayes, William K., Kent R. Beaman, Michael D. Cardwell, and Sean P. Bush, editors. The Biology of Rattlesnakes. Loma Linda University Press, 2009.

Hubbs, Brian R., & Brendan O'Connor. A Guide to the Rattlesnakes and other Venomous Serpents of the United States. Tricolor Books, 2011.

Klauber, Laurence M. Rattlesnakes. University of California Press. (Abridged from the 1956 two volume Rattlesnakes: Their Habits, Life Histories, and Influence on Mankind.) University of California Press, 1982.

Rubio, Manny. Rattlesnake - Portrait of a Predator. Smithsonian Institution Press, 1998.

Walls, Jerry G. Rattlesnakes: Their Natural History and Care. T. F. H. Publications, Inc., 1996.



Conservation Status

The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.

This snake is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.


Organization
Status Listing
U.S. Endangered Species Act (ESA)
California Endangered Species Act (CESA)
California Department of Fish and Game
Bureau of Land Management
USDA Forest Service
Natureserve Global Conservation Status Ranks
World Conservation Union - IUCN Red List





 

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