Found in northern Siskiyou and Modoc counties and in south central Oregon, this intergrade was once considered a unique subspecies: Thamnophis elegans biscutatus - Klamath Gartersnake.
More pictures of this intergrade snake can be viewed here.
A medium-sized slender snake with a head barely wider than the neck and keeled dorsal scales.
Some scale averages: Average of 8 upper labial scales, occasionally 7, scales 6 and 7 are enlarged, higher than wide. Average of 10 lower labial scales. The front and rear pair of chin shields are equal in length. The internasals are wider than long and not pointed in front. Average scale count at mid-body is 21, rarely 19.
Color and Pattern
Ground color is a dark olive-brown or black with no red markings.
3 well-defined light stripes on the back and sides:
The dorsal stripe is yellow, orange, or white.
The lateral stripes may be paler. Underside is pale with few markings, and is sometimes darker in the center.
Active in daylight. Chiefly terrestrial - not as dependant on water as other gartersnake species, but more likely to be found near water.
If frightened when picked up, this snake will often strike repeatedly and release cloacal contents.
When frightened, this species will sometimes seek refuge in vegetation or ground cover, but it will also crawl quickly into water and swim away from trouble.
Western Terrestrial Gartersnakes - Thamnophis elegans - eat a wide range of prey (among the widest of any snake species - Rossmann, et al. 1996.) The prey depends on the size of the snake (large snakes tend to eat larger prey, small snakes can only eat smaller prey) and what prey is available. Populations found on the humid North Coast where slugs are abundant are genetically predisposed to eat slugs, while populations in dryer areas where slugs are less common refuse to eat slugs when they are offered. (Rossmann, et al. 1996.)
Diet includes: invertebrates such as slugs, leeches, snails, and earthworms; fish; amphibians - tadpoles, frogs, (and probably salamanders); snakes and lizards;
birds; and small mammals such as mice and voles (and bats as you can see in the pictures above.)
At high elevations in the Sierra Nevada, Mountain Gartersnakes rely almost exclusively on amphibians for food, mostly Sierran Treefrogs.
Thamnophis elegans terrestris has been found in San Luis Obispo County eating Taricha torosa, which are deadly poisonous to most predators.
(Feldman, Hansen, & Sikola. Herpetological Review 51 2020.)
It's possible that T. e. elegans is also able to develop a resistance to newt toxins.
Mating occurs primarily in spring, with young born live July to Sepember.
Inhabits streamsides, springs, mountain lakes, in grassland, meadows, brush, woodland, and coniferous forest.
In California, the subspecies Thamnophis elegans elegans - Mountain Gartersnake, is found throughout the Sierra Nevada Mountains, through most of the northern part of the state except for the outer Coast Ranges south at least as far as Mt. St. Helena. There is an isolated population in the San Bernardino Mountains.
The subspecies ranges out of the state north into Oregon and to the edge of northern Nevada.
Most range maps showing subspecies of T. elegans, show T. e. elegans occurring in the Central Valley near Lodi. Previously I changed my maps to show T. e. terrestris there based on the one bright red snake from Lodi seen above, but discussions with a herpetologist in that area have convinced me that they are T. e. elegans. It's likely that the wild-caught Lodi specimen was transported there.
The species Thamnophis elegans - Western Terrestrial Gartersnake, ranges widely from the California coast north through most of northern California, Oregon, Washington, Idaho and Montana, into Canada, including Vancouver Island, British Columbia, Alberta and Saskatchewan, and east into the states of Wyoming, Colorado, Utah, Arizona and New Mexico and just barely making it into South Dakota, Nebraska, and Oklahoma. Many isolated populations exist, including those in the San Bernardino Mountains and one in Baja California Norte, Mexico (the San Pedro Martir Gartersnake.)
The species Thamnophis elegans - Western Terrestrial Gartersnake, occurs from sea level to 13,100 ft. (3,990 m) in elevation in Colorado. (Stebbins, 2003)
Notes on Taxonomy
T. e. vagrans intergrades withT. e. elegans in northeast California in Modoc and eastern Siskiyou counties and in south central Oregon (this snake was formerly classified as the subspecies Thamnophis elegans biscutatus - Klamath Gartersnake. Intergrades with T. e. elegans also occur along the southern and southeastern edge of the Sierras.
Rossman, Ford, and Seigel (1996) emphasize that a detailed study of geographic variation throughout the range of Thamnophis elegans is badly needed.
Bronikowski and Arnold (2001, Copeia 2001:508-513) found several clades within T. elegans that do not always follow the subspecies boundaries, and concluded that there was no support for the race terrestris. Presumably, the former T. e. terrestris snakes become T. e. elegans.
Hammerson (1999, Amphibians and Reptiles of Colorado. 2nd ed. Univ. of Colorado Press) synonymized T. e. arizonae and T. e. vascotanneri but retained three subspecies, T. e. vagrans, T. e. elegans, and T. e. terrestris.
Not known to be threatened, but gartersnakes have been negatively impacted by competition with introduced bullfrogs and non-native fish in some areas. High-altitude populations of this snake may decline if populations of high-altitude frogs continue to decline.
North American Gartersnakes
Western Terrestrial Gartersnake
(Baird and Girard, 1853)
(Baird and Girard, 1853)
Thamnophis elegans - (Baird and Girard, 1853) - Cat. N. Amer. Rept., Pt. 1, p. 34
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.
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.
The following conservation status listings for this animal are taken from the November 2020 California "Special Animals List" and the November 2020 "State and Federally Listed Endangered and Threatened Animals of California" list, both of which are produced by multiple agencies and available here: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. You can check the link to see if there are more recent lists.
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 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.