iPhone App
Electronic Field Guide to the
Reptiles and Amphibians of
Southern California
Available Now at the
iTunes App Store. |
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Venomous and Potentially Dangerous!
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Adult, Riverside county
© William Flaxington |
Adult, Riverside county
© William Flaxington
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Adult, Imperial County (Calexico)
© Tom Millington |
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Adult, Riverside County
© Patrick Briggs |
Adult, Riverside County
© Chad Lane |
Adult, Imperial County at Colorado River
© John Sullivan |
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| 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 two large scales between the supraoculars of the Northern Mohave Rattlesnake. |
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Tail and Rattle
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| Western Diamond-backed Rattlesnakes From Outside California |
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Adult in the typical Diamondback threatening
defensive posture, Sierra County, New Mexico. |
Adult, Cochise County, Arizona
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Adult, Webb County, Texas
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Adult, from just across the Colorado River from California in
La Paz County, Arizona
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Adult, Presidio County, Texas |
| Feeding |
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| A Western Diamond-backed Rattlesnake eats a dove in Cochise County, Arizona. © Bob Herrmann |
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Juvenile eating a rodent on a road at night, Hidalgo County, New Mexico
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| Habitat |
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| Habitat, Imperial County desert |
Habitat, Imperial County desert |
Habitat, New River, Imperial County |
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| Habitat, Imperial County desert |
Habitat, Riverside County desert |
Habitat, Imperial County |
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| Habitat, Imperial County desert |
California National Wildlife Refuge warning sign, Imperial County.
Click the picture to see more rattlesnake signs.
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| Short Videos and Sound |
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| 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.) |
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California Park warning sign.
Click the picture to see more
rattlesnake signs.
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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.
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"Rattlesnakes are also among the most reasonable forms of dangerous wildlife: their first line of defense is to remain motionless; if you surprise them or cut off their retreat, they offer an audio warning; if you get too close, they head for cover. Venom is intended for prey so they're reluctant to bite, and 25 to 50 percent of all bites are dry - no venom is injected."
Leslie Anthony. Snakebit: Confessions of a Herpetologist. Greystone Books, 2008.
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Rattlesnake bites can be extremely dangerous, but rattlesnakes should not be considered vicious and aggressive. They are often called aggressive in movies and stories, but they will not attack without a reason. The image of a rattlesnake we often see in pictures and film, with the body partly coiled, the tail rattling loudly, and the head up ready to strike, is a defensive stance some rattlesnakes use when they sense that crawling away would put them in danger of an attack. This display is a warning not to come any closer or they will strike. If they are given some space and some time to escape to a safe place, they will do so quickly.
Because they cannot move very quickly rattlesnakes often use their cryptic color and pattern to blend into their surroundings to hide from their prey and from other animals that could threaten them. When threatened, they often lie still to avoid detection and do not rattle, because that would give away their location. At other times they rattle loudly, sometimes from a good distance, to warn potential enemies of their presence. In both cases they are doing everything they can to avoid confrontation and to avoid striking and biting and using up their valuable supply of venom which they need to kill and digest their food.
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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.
(The 1990 California Dept. of Fish and Game California Wildlife Habitat Relationships System range map for the species shows it ranging farther west into San Diego County, overlapping the range of C. ruber.)
Outside of California, ranges through Arizona, New Mexico to Oklahoma Arkansas and East Texas, and south 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. |
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Taxonomy |
| Family |
Viperidae |
Vipers |
Crotalidae - Pitvipers |
| Genus |
Crotalus |
Rattlesnakes |
Linnaeus, 1758 |
Species
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atrox |
Western Diamond-backed Rattlesnake |
Baird and Girard, 1853 |
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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
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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
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Alternate Names |
Western Diamondback Rattlesnake
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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
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More Information and References |
California Department of Fish and Wildlife
Living With Rattlesnakes
California Department of Fish and Game: Rattlesnakes in California
University of California: Rattlesnakes Management Guide
Tucson Herpetological Society: Living With Venomous Reptiles pdf
Florida Museum of Natural History: How to Get Along with Snakes
Southwestern Field Herping Associates: Venomous Snake Safety
Internet Center for Wildlife Damage Management - Rattlesnake Control / Snake Control
Rattlesnake Bites
California Poison Control System (search for "rattlesnake bite")
University of Arizona:
Rattlesnakes
Justin Schwartz' Rattlesnake Bite Story and Pictures
Sean Bush MD: Venom ER - When snakes strike!
eNature - How to Avoid Snakebites and How to Treat One
When a Pet Gets Snake Bitten: The amazing story of Andy Cat, a very lucky cat who was bitten by a rattlesnake and survived, thanks to the smart actions of its owners.
Stebbins, Robert C., and McGinnis, Samuel M. Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.
Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.
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.
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| Conservation Status |
The following status listings come from the Special Animals List and the Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.
This snake is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.
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Organization
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Status Listing
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| U.S. Endangered Species Act (ESA) |
None |
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| California Endangered Species Act (CESA) |
None |
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| California Department of Fish and Wildlife |
None |
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| Bureau of Land Management |
None |
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| USDA Forest Service |
None |
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