CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Marcy's Checkered Gartersnake  -
Thamnophis marcianus marcianus

(Baird and Girard, 1853)
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Marcy's Checkered Gartersnake California Range Map
Range in California: Red

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observation link





Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake
Adult, Imperial County
© 2005 William Flaxington
Adult, Imperial County
© 2005 William Flaxington
Juvenile, Riverside County
© Jeremiah Easter
     
Marcy's Checkered Gartersnakes From Outside California
Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake
Adult, Cochise County, Arizona
Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake
  Adult, Cochise County, Arizona  
Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake Marcy's Checkered Gartersnake
  Adult, Starr County, Texas  
     
Habitat
Marcy's Checkered Gartersnake Habitat Marcy's Checkered Gartersnake Habitat Marcy's Checkered Gartersnake Habitat
Habitat, agricultural drain, Imperial County
Habitat, Colorado River, Imperial County Habitat, Colorado River, Imperial County
Marcy's Checkered Gartersnake Habitat Marcy's Checkered Gartersnake Habitat  
Habitat, agricultural drain, Imperial County
Habitat, agricultural drain, Imperial County
 
   
Description

Not Dangerous (Non-poisonous)  -  This snake does not have venom that is dangerous to most humans.

Gartersnakes have toxins in their saliva which can be deadly to their prey and their bite might produce an unpleasant reaction in humans, but they are not considered dangerous to humans.

Size
13 - 42 inches long (32 - 107 cm). Normally found from 20 - 28 inches (51 - 71 cm).
Neonates from 6.5 - 9.5 inches (17 - 24 cm).

Appearance
A medium-sized snake with a head barely wider than the neck and keeled dorsal scales.
Color and Pattern
Tan, brown or yellowish brown with rows of large alternating black blotches arranged in a checkered pattern on the sides, and distinct yellowish stripes on the back and lower sides.
There is a dark blotch on the back of each side of the head with a light area between the dark blotch and the corner of the mouth.
The underside is pale and unmarked or smudged with dark pigment.
Key to Identifying California Gartersnake Species

Life History and Behavior

Activity
Can be diurnal, crepuscular, and nocturnal, especially in hot weather.
A good swimmer. May dive when startled.
Defense
Like most gartersnakes, when picked up, this snake will often release its cloacal contents and musk.
Diet and Feeding
Checkered Gartersnakes consume mostly amphibians, but they also eat invertebrates, fish, snakes, mammals, and lizards, including whiptails, one of which was found in the stomach contents of a Checkered Gartersnake in New Mexico. (Herpetological Review 38(1), 2007)
Breeding
Bears live young from May to October.

Geographical Range
Found in southeast California along the Colorado river and the Imperial Valley in Imperial and Riverside counties.

Outside of California, ranges into extreme northern Baja California, southern Arizona, much of New Mexico, Texas, Oklahoma, southern Kansas, and northern Mexico.

Full Species Range Map
Habitat
Found in grassland, semi-arid land, and deserts, typically near water. In California, inhabits areas near streams, rivers, irrigation ditches, and irrigated croplands, in the desert.

Notes on Taxonomy
There are three subspecies of Thamnophis marcianus, two occur in Mexico and south to Costa Rica.

Alternate and Previous Names (Synonyms)

Thamnophis marcianus -
Checkered Garter Snake (Stebbins 1954, 1966, 1985, 2003, 2012)
Thamnophis marcianus nigrolateris
(Brown 1889)
Sonoran garter snake;
Marcy's garter snake

Conservation Issues  (Conservation Status)
Possibly increasing their range due to irrigation in the desert. Apparently not negatively affected by introduced Bullfrogs.
Taxonomy
Family Colubridae Colubrids Oppel, 1811
Genus Thamnophis North American Gartersnakes Fitzinger, 1843
Species marcianus Checkered Gartersnake (Baird and Girard, 1853)
Subspecies

marcianus Marcy's Checkered Gartersnake (Baird and Girard, 1853)
Original Description
Thamnophis marcianus - (Baird and Girard, 1853) - Cat. N. Amer. Rept., Pt. 1, p. 36

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

Meaning of the Scientific Name
Thamnophis - Greek - thamnos - shrub or bush, and ophis - snake, serpent
marcianus
- honors Marcy, Randolph B.

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

Alternate Names
Thamnophis marcianus - Checkered Garter Snake (no subspecies recognized)
Northern Checkered Gartersnake

Other California Gartersnakes
T. a. atratus - Santa Cruz Gartersnake
T. a. hydrophilus - Oregon Gartersnake
T. a. zaxanthus - Diablo Range Gartersnake
T. couchii - Sierra Gartersnake
T. gigas - Giant Gartersnake
T. e. elegans - Mountain Gartersnake
T. e. terrestris - Coast Gartersnake
T. e. vagrans - Wandering Gartersnake
T. hammondii - Two-striped Gartersnake
T. ordinoides - Northwestern Gartersnake
T. s. fitchi - Valley Gartersnake
T. s. infernalis - California Red-sided Gartersnake
T. s. tetrataenia - San Francisco Gartersnake

More Information and References
California Department of Fish and Wildlife

Rossman, Douglas A., Neil B, Ford, & Richard A. Siegel. The Garter Snakes - Evolution and Ecology. University of Oklahoma press, 1996.

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, 1957.


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.
Organization
Status Listing
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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