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A Guide to the Amphibians
and Reptiles of California


Red Diamond Rattlesnake - Crotalus ruber

Cope, 1892
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Range Map
Range in California: Red


observation link



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Venomous and Potentially Dangerous!

Red Diamond Rattlesnake
Adult, coastal San Diego County
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
Adult, Imperial County desert, found in ambush mode coiled up in the sand between rocks at night. Adult, San Diego County desert Adult, San Diego County desert
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
  Adult, coastal San Diego County   Adult, Imperial County desert
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake tracks Red Diamond Rattlesnake tracks
Adult, crossing a popular hiking trail in coastal San Diego County in the middle of the afternoon, managing
to avoid observation by all visitors except myself. You can see the tracks it made in the sand on the right.
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
3 adults found under the same rock in early March in San Diego County.
© Stuart Young
Adult, San Diego County. Specimen courtesy of Tim Burkhardt Juvenile, desert slope of San Diego County mountains Adult, crawling on boulder at night,
San Diego County desert
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
Adult, coastal Riverside County
© 2005 Jeremiah Easter
Adult, San Diego County
© Jason Jones
Adult, coastal Riverside County
© Brad Alexander
Adult, Riverside County
© Michael Clarkson
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
Adult, San Diego County desert. © Lori Paul Adult, San Diego County
© Ryan Shatto
Adult, San Diego County
© Ryan Shatto
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
Adult, foothills of Santa Ana Mountains, Orange County. © Jay Selman Adult, Riverside County © John Worden Juvenile, Riverside County © Tom Harkins Adult, San Diego County
© John Stoklosa
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
This adult snake from Riverside County was seen crawling through grass and over rocks to this sunny basking spot. © Jeff Ahrens

Head of adult Juvenile head, San Diego County
© Patrick Briggs

Tail with rattle
Breeding
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake  
Adults mating in San Diego County © Shelly Hancock

Males in combat, Riverside County
© Gregory Litiatco
A male guards an uninterrested female hoping to mate with her if she becomes receptive. You can see a video of this pair on YouTube. © Gregory Litiatco  
       
Feeding
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake  
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake  
Bob Martz found this adult Red Diamond Rattlesnake swallowing a brush rabbit when he was hiking on a hillside in Riverside County. After taking a few photographs, he left quickly so he would not scare the snake and cause it to disgorge its meal. But on his return he saw that the snake had left the rabbit uneaten, probably because it was too big for the snake to swallow.
© Bob Martz

 
Habitat
Red Diamond Rattlesnake Habitat Red Diamond Rattlesnake Habitat red diamond rattlesnake habitat Red Diamond Rattlesnake Habitat
Habitat, San Diego County desert canyon Habitat, rocky hillside, coastal
Riverside County
Habitat, Riverside County -
riparian desert foothills
Habitat, San Diego County desert oasis
Red Diamond Rattlesnake Habitat Red Diamond Rattlesnake Habitat Red Diamond Rattlesnake Habitat Red Diamond Rattlesnake Habitat
Habitat, desert slope of
San Diego County mountains
Habitat, hillside coastal chaparral,
San Diego County
Habitat, riparian canyon
coastal San Diego County
Coastal habitat, San Diego County
Red Diamond Rattlesnake Habitat Red Diamond Rattlesnake Habitat california kingsnake habitat snake habitat
Habitat, desert boulder piles
Imperial County

Habitat, rocky hillside,
Riverside County © Brian Hinds
Coastal scrub habitat,
San Diego County
Habitat, Riverside County
riparian desert foothills
Short Videos and Sound
Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake Red Diamond Rattlesnake
A large old Red Diamond Rattlesnake rattles on top of a boulder in coastal San Diego County. A close view of a rattling Red Diamond Rattlesnake's tail. A large adult Red Diamond Rattlesnake crawls up some large boulders at the edge of a desert wash in San Diego County. After trying to climb up past the top of the boulder, it crawled back down. Despite the bright lights, it did not appear to notice me and continued its nocturnal wandering. A Red Diamond Rattlesnake crawls across the hot sand at mid day in San Diego County, then takes shelter between some rocks.
Red Diamond Rattlesnake speaker icon

   
A Red Diamond Rattlesnake found on a desert road at night.

Listen to a rattlesnake rattling.
   
 
sign sign rattlesnake sign
  California State Park warning sign.
Click the picture to see more rattlesnake signs.

 

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.

"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.

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.

Description

Venomous
The venom of this snake is potentially dangerous to humans.
Size
Adults are 30 - 65 inches in length ( 76 - 165 cm) typically 2 - 4.5 feet long. Young about 12 inches long.
(Unlike most snake species, males of this species tend to be larger in body length than females.)
Appearance
A heavy-bodied, venomous pit viper, with a thin neck and a large triangular head. Pupils are elliptical. Scales are keeled.

Variable in ground color; pink, reddish-tan, reddish-brown or brick red. Diamond-shaped blotches, usually with light edges, mark the back. Juveniles are duller in coloring than adults. The underside is usually dull yellow and unmarked. Black and white rings surround a thick tail. A rattle, consisting of loose interlocking segments, usually occurs at the end of the tail. 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.

Similar to and easily confused with the Western Diamond-backed Rattlesnake, but in California the ranges of these two snakes barely meet, and the Western Diamond-backed Rattlesnake in Calfornia does not typically show a red color phase.

Heat sensing pits on the sides of the head 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 prey. The snake can control the amount of venom injected and the fangs are replaced if broken. Bites on humans are potentially dangerous 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 and crepuscular during periods of excessive daytime heat, but also active during daylight when the temperature is more moderate or when in the comparatively cooler shaded areas of boulder fields. Not active during cooler periods in Winter. Terrestrial, but may partially climb shrubs or trees.

Prey is found when actively moving, or by ambush, where the snake waits near lizard or rodent trails, striking at and releasing passing 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. Juveniles are born with only a silent button at the end of the tail.
Diet
Eats small mammals, including ground squirrels, wood rats, and rabbits, lizards, and birds.
(Adult California Ground Squirrels are immune to rattlesnake venom and will intensely confront any snake they feel to be a threat.)

Dugan and Hayes, 2012, found that this species specializes on mammalian prey, with terrestrial rodents the primary prey source. Wood rats were the most abundant prey species, followed by kangaroo rats, pocket mice, and deer mice. Coastal populations average longer in body size and eat a higher proportion of larger rodents than snakes from desert populations.
Reproduction
Breeding occurs in the spring. Male rattlesnakes search extensively for females during the mating season while females do not actively search for males. Male to male combat occurs.
Live-bearing; young are born July - September.
Range
Found in southwestern California, from the Morongo Valley west to the coast and south along the peninsular ranges to mid Baja California.
Habitat
Inhabits arid scrub, coastal chaparral, oak and pine woodlands, rocky grassland, cultivated areas. On the desert slopes of the mountains, it ranges into rocky desert flats.
Taxonomic Notes
Previously recognized as a subspecies of Crotalus ruber: Crotalus ruber ruber. Some taxonomists regard this snake as a subspecies of Crotalus exsul labelling it Crotalus exsul ruber.
Conservation Issues  (Conservation Status)
A CA Dept. of Fish and Game California Species of Special Concern, due to habitat loss in the coastal region. Protected from take with a sport fishing license.

Taxonomy
Family Viperidae Vipers Crotalidae - Pitvipers
Genus Crotalus Rattlesnakes Linnaeus, 1758
Species


ruber Red Diamond Rattlesnake Cope, 1892
Original Description
Crotalus ruber - Cope, 1892 - Proc. U.S. Natl. Mus., Vol. 14, p. 690

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
ruber
- Latin - red - referring to the reddish color of dorsum Cope, 1892

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

Alternate Names
Crotalus exsul

Related or Similar California Snakes
C. atrox - Western Diamond-backed Rattlesnake
C. s. scutulatus - Northern Mohave Rattlesnake
C. c. laterorepens - Colorado Desert Sidewinder
C. m. pyrrhus - Southwestern Speckled Rattlesnake
C. o. helleri - Southern Pacific Rattlesnake

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.

Eric A. Dugan and William K. Hayes. Diet and Feeding Ecology of the Red Diamond Rattlesnake, Crotalus Ruber (Serpentes: Viperidae)
Herpetologica, 68(2), 2012, 203–217 E 2012 by The Herpetologists’ League, Inc.

Eric A. Dugan, Alex Figueroa, and William K. Hayes. Home Range Size, Movements, and Mating Phenology of Sympatric Red Diamond (Crotalus ruber) and Southern Pacific (C. oreganus helleri) Rattlesnakes in Southern California. Pp. 353-364 in W. K. Hayes, K. R. Beaman, M. D. Cardwell, and S. P. Bush (eds.), The Biology of Rattlesnakes. Loma Linda University Press. 2008.


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.



Organization
Status Listing
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife DFG:SSC California Species of Special Concern
Bureau of Land Management None
USDA Forest Service None

 

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