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)

Click on a picture for a larger view

Description • Taxonomy • Species Description • Scientific Name • Alt. Names • Similar Herps • References • Conservation Status

Red: Range in California

Click on the map for a topographical view

Map with California County Names

Northwest Page

Adult, Siskiyou County

Adult, Yuba County

Adult, San Mateo County

Adult, Tule Lake, Siskiyou County

Adult, in shedding phase, Sutter County

Adult, Sonoma County

Adult, Marin County

Adult, Modoc County © Max Roberts

Adult, San Mateo County

Adult, Lassen County © Loren Prins

Adult, Lassen County © Debbie Frost

Adult, El Dorado County.
© Richard Porter

Adult with reddish coloring, El Dorado County. © Richard Porter

Adult, San Luis Obispo County
© Andrew Harmer

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

Adult, Yolo County © Zach Lim

Adult, Orange County © Nicholas Hess

Adult, Del Norte County.
© Alan D. Barron

Adult, Solano County © Lou Silva

Adult, San Diego County © Ryan Wolter

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

Adult, San Luis Obispo County
© Joel A. Germond

Adult, Santa Monica Mountains, Los Angeles County © Huck Triggs

Adult, San Mateo County © Faris K

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

Adult, Santa Cruz County
© Marcus Rehrman

Adult, Monterey County. Racers sometimes "periscope" raising their head up high to get a better view in tall grass. © Ryan Sikola

Adult, Modoc County © Max Roberts

Western Yellow-bellied Racer tracks, Sutter County

Adult, Yakima County, Washington

Juveniles

Juvenile, Modoc County

Juvenile, San Mateo County

Juvenile, Contra Costa County

Juvenile, San Mateo County

Juvenile, Del Norte County.
© Alan D. Barron

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

Juvenile, Kern County
© Brad Alexander

Juvenile, Santa Clara County © Noah Morales

Juvenile, Alameda County
© Mandy Colombo Murphy

Juvenile, Modoc County © Max Roberts

Juvenile, © Kenny Elliott

Juvenile, San Mateo County

Breeding Behavior

A pair of breeding adult racers in a Contra Costa County back yard. © Cheryl Haga

Feeding

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

Habitat, Modoc County
Great Basin desert

Habitat, Marin County grasslands

Habitat, San Mateo County riparian

Habitat, Tuolumne County mountains

Habitat, 4,100 ft. Siskiyou County

Habitat, Glenn County,
Sacramento Valley

Habitat, Sutter County agricultural fields

Short Videos

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.

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. Taylor, Emily. California Snakes and How to Find Them. Heyday, Berkeley, California. 2024. 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 April 2024 State of California Special Animals List and the April 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. Check the current California Department of Fish and Wildlife sport fishing regulations to find out if this animal can be legally pursued and handled or collected with possession of a current fishing license. You can also look at the summary of the sport fishing regulations as they apply only to reptiles and amphibians that has been made for this website. 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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