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A Guide to the Amphibians
and Reptiles of California



North American Racer - Coluber constrictor

Western Yellow-bellied Racer - Coluber constrictor mormon

Baird and Girard, 1852

(= Coluber mormon)

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Red: Range in California


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Map with California County Names




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western yellow-bellied racer
Adult, Siskiyou County
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
  Adult, Yuba County   Adult, Sonoma County
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, Tule Lake, Siskiyou County Adult, San Mateo County Adult, Marin County
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
  Adult, in shedding phase, Sutter County  
western yellow-bellied racer
western yellow-bellied racer
western yellow-bellied racer western yellow-bellied racer
Adult, San Mateo County Adult, Lassen County © Loren Prins Adult, Lassen County  © Debbie Frost
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, El Dorado County.
© Richard Porter
Adult with reddish coloring, El Dorado County. © Richard Porter Adult, San Luis Obispo County
© Andrew Harmer
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, Santa Cruz Island © Ken Owen
Channel Islands Restoration
Adult, Santa Cruz Island
© Luke Caldwell
Adult, Tulare County © Patrick Briggs Adult with lots of green coloring,
Yolo County.  Dave Feliz
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, Yakima County, Washington Adult, Orange County © Nicholas Hess
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, Del Norte County.
© Alan D. Barron
Adult, Solano County © Lou Silva Adult, Yolo County © Zach Lim Adult Western Yellow-bellied Racers are typically about 3 feet in length. This one found in Yolo County is almost four feet long. © Richard Porter
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, San Luis Obispo County
© Joel A. Germond
Adult, Santa Monica Mountains, Los Angeles County © Huck Triggs Adult, San Diego County © Ryan Wolter
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult in habitat, Alameda County
© Mandy Colombo Murphy
Adult, San Mateo County © Emile Bado Adult crossing a road in late afternoon, Modoc Plateau, Siskiyou County

western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Adult, Santa Cruz County
© Marcus Rehrman
Adult, San Mateo County © Faris K Adult, Modoc County © Max Roberts
western yellow-bellied racer western yellow-bellied racer tracks    
Adult, Modoc County © Max Roberts Western Yellow-bellied Racer tracks, Sutter County
   
       
Juveniles
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer
Juvenile, Modoc County Juvenile, San Mateo County
western yellow-bellied racer western yellow-bellied racer western yellow-bellied racer California Glossy Snake
Juvenile, Contra Costa County
western yellow-bellied racer
western yellow-bellied racer
western yellow-bellied racer western yellow-bellied racer
Juvenile, San Mateo County Juvenile, Del Norte County.
© Alan D. Barron
western yellow-bellied racer western yellow-bellied racer racer racer
Juvenile, Butte County
© Jackson Shedd
Juvenile, Butte County
© Rodney Lacey
This juvenile from San Luis Obispo County shows the dull colors and milky eye of a snake about to shed its skin. © Joel A. Germond
western yellow-bellied racer racer racer racer
Juvenile, Kern County
© Brad Alexander
Juvenile, Santa Clara County © Noah Morales Juvenile, Alameda County
© Mandy Colombo Murphy
western yellow-bellied racer racer western yellow-bellied racer
Juvenile, Modoc County © Max Roberts Juvenile, © Kenny Elliott Juvenile, San Mateo County
       
Breeding Behavior
western yellow-bellied racer western yellow-bellied racer    
A pair of breeding  adult racers in a Contra Costa County back yard. © Cheryl Haga
   
     
Feeding
western yellow-bellied racer western yellow-bellied racer  

 An adult Western Yellow-bellied Racer was observed trying to swallow an Aquatic Gartersnake on a lawn in Sonoma County, but the observers apparently spooked the racer, which dropped the gartersnake then climbed a rose bush. © Don KcKee

 
       
Habitat
western yellow-bellied racer habitat western yellow-bellied racer habitat western yellow-bellied racer habitat western yellow-bellied racer habitat
Habitat, Modoc County
Great Basin desert
Habitat, Marin County grasslands Habitat, San Mateo County riparian Habitat, Tuolumne County mountains
coluber habitat western yellow-bellied racer habitat western yellow-bellied racer habitat western yellow-bellied racer habitat
Habitat, 4,100 ft. Siskiyou County
Habitat, Glenn County,
Sacramento Valley
Habitat, Sutter County agricultural fields Vernal pools grasslands habitat,
Butte County © Rodney Lacey
western yellow-bellied racer habitat western yellow-bellied racer habitat Western Black-headed Snake Habitat  
Habitat, Santa Monica Mountains,
Los Angeles County © Huck Triggs
Habitat, Santa Monica Mountains,
Los Angeles County © Huck Triggs
Habitat, Alameda County
© Mandy Colombo Murphy
 
       
Short Videos
western yellow-bellied racer video western yellow-bellied racer video western yellow-bellied racer video  
A large adult racer in bad need of a shed on the crawl in the Sacramento Valley. A little blotched juvenile racer strikes and crawls away defensively in the Modoc County Great Basin Desert. A juvenile racer found under a rock in late January in Contra Costa County.  
     
Description

Not Dangerous - This snake does not have venom that can cause death or serious illness or injury in most humans.

Commonly described as "harmless" or "not poisonous" to indicate that its bite is not dangerous, but "not venomous" is more accurate. (A poisonous snake can hurt you if you eat it. A venomous snake can hurt you if it bites you.)

Size
Adults of the species are 20-75 inches long (51-190 cm), but snakes in California are typically under 3 feet long 91cm).
Hatchlings are 8 - 11 inches long (20 - 28 cm).

Appearance
A slender snake with large eyes, a broad head and a slender neck, smooth scales, and a long thin tail.
Color and Pattern
Plain brown, blue-grey, or olive-green to green above and unmarked off-white or yellowish below.
Young
Young have dark blotches on the sides and 70 - 85 dark blotches on the back.

At one time juveniles were thought to be a different species of snake than the adults due to the dramatic difference in appearance between the blotched juveniles and the plain-colored adults.

Life History and Behavior

Activity
Active in daylight.
Mainly terrestrial, but also a good climber.
Can be found in winter at denning sites along with other species of snakes.
Moves very quickly.
Often bites agressively.
Diet and Feeding
Eats lizards, small mammals, birds, eggs, snakes, small turtles and frogs, and large insects.

Cannibalism has been observed. (Herpetological Review 38(2), 2007)

Hunts crawling with head held high off the ground, sometimes moving it from side to side. Prey is killed by being quickly overcome and captured, crushed with the jaws or trapped under the body, and swallowed alive. Despite the species name, this snake is not a constrictor.
Reproduction
Females are oviparous, laying 3 - 11 eggs in mid summer, sometimes in communal nests.
Eggs hatch in late summer. (Stebbins & McGinnis 2012)

Habitat
Prefers open areas with sunny exposure - meadows, grassland, sagebrush flats, brushy chaparral, woodlands, riparian areas such as pond edges, and forest openings. Found in arid and moist habitats, but not usually found in deserts or high mountains.

Geographical Range
This subspecies, Coluber constrictor mormon - Western Yellow-bellied Racer, is found throughout most of california north and west of the Sierras, and south along the coast to the Baja California border. It is also found on Santa Cruz Island.

Outside of California the subspecies continues north through Oregon and eastern Washington into British Columbia, Canada, and east through parts of Idaho, Montana, and Utah into western Colorado, with some isolated populations in eastern Arizona and northwestern New Mexico.

The species Coluber constrictor - North American Racer, is very wide-ranging, occurring from coast to coast and from British Columbia all the way south to Guatemala.

Full Species Range Map
Elevational Range
Occurs from sea level to around 7,000 feet in elevation (2134 m).

Notes on Taxonomy
Coluber constrictor consists of 11 subspecies, but some herpetologists consider C. c. mormon to be a full species, Coluber mormon.

According to the SSAR list "Burbrink et al. (in rev.) have demonstrated using mtDNA that C. constrictor may be composed of six independently evolving lineages not concordant with most recognized subspecies."


Alternate and Previous Names (Synonyms)

Coluber constrictor mormon - Western Yellow-bellied Racer (Wright & Wright 1957, Stebbins 1966, 1985, 2003, 2012)
Coluber constrictor mormon - ssp. of Racer (Stebbins 1954)
Coluber constrictor vetustus - Western Yellow-bellied Racer (Bascanion vetustus; Bascanion constrictor flaviventris; Bascanion constrictor vetustum; Zamenis constrictor flaviventris; Bascanion constrictor; Zamenis constrictor; Bascanium fagelliformae testaceum, part. Bue Racer; California Black Snake; Black Chaser; Yellow Coachwhip Snake, part; Yellow-bellied Black Snake; Green Racer) (Grinnell and Camp 1917)
Coluber mormon (Baird and Girard 1852)

Conservation Issues  (Conservation Status)
Common and abundant in much of its range, but absent from some historical range areas along the south coast.

Taxonomy
Family Colubridae Colubrids Oppel, 1811
Genus Coluber North American Racers, Coachwhips and Whipsnakes Linnaeus, 1758
Species constrictor North American Racer Linnaeus, 1758
Subspecies


mormon Western Yellow-bellied Racer Baird and Girard, 1852
Original Description
Coluber mormon - Baird and Girard, 1852 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 6, p. 70

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

Meaning of the Scientific Name
Coluber - Latin - coluber snake or serpent
constrictor
- Latin - one that constricts - misnomer, genus does not constrict
mormon - Mormon - "found by Capt. Howard Stansbury's party, in the valley of the Great Salt Lake" settled by Mormon religionists

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

Related or Similar California Snakes
M. f. ruddocki - San Joaquin Coachwhip
M. f. piceus - Red Coachwhip
P. c. annectens - San Diego Gophersnake
P. c. catenifer - Pacific Gophersnake
M. l. lateralis - California Striped Racer
M. l. euryxanthus - Alameda Striped Racer

More Information and References
California Department of Fish and Wildlife

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.

Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021.

Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.

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, 1957.

Joseph Grinnell and Charles Lewis Camp. A Distributional List of the Amphibians and Reptiles of California. University of California Publications in Zoology Vol. 17, No. 10, pp. 127-208. July 11, 1917.

Conservation Status

The following conservation status listings for this animal are taken from the January 2024 State of California Special Animals List and the January 2024 Federally Listed Endangered and Threatened Animals of California list (unless indicated otherwise below.) Both lists are produced by multiple agencies every year, and sometimes more than once per year, so the conservation status listing information found below might not be from the most recent lists. To make sure you are seeing the most recent listings, go to this California Department of Fish and Wildlife web page where you can search for and download both lists:
https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals.

A detailed explanation of the meaning of the status listing symbols can be found at the beginning of the two lists. For quick reference, I have included them on my Special Status Information page.

If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can also go to the NatureServe and IUCN websites to check their rankings.

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  Notes
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None
IUCN

 

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