Range in California: Red
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Electronic Field Guide to the
Reptiles and Amphibians of
Southern California
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Sub-adult, San Diego County |
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| Sub-adult, San Diego County |
Adult, San Diego County © Taylor Henry |
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| Adult, preparing to shed, coastal San Diego County |
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| Sub-adult, spotted morph, Cottonwood Creek, San Diego County |
Adult, striped morph, Santa Barbara County © Brian Hubbs |
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Adult, spotted morph (with faint stripes), Laguna Mountains,
San Diego County © John Stoklosa |
Sub-adults, two color phases,
Ventura County. © Brian Hubbs |
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Adult, Santa Barbara County
© Jason Butler |
An adult snake with a reddish stripe from just west of the Piru River in Ventura County. © Vince Semonsen |
Adult, Ventura County © Jeremy Huff |
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Adult from the Mohave Desert at Victorville,
San Bernardino County © Michael Clarkson |
Adult, Ventura County © Patrick Briggs |
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Dark morph snake, with no stripes or spots,
San Luis Obispo County © Katie Drexhage |
Adult, preparing to shed,
San Diego County |
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| This snake typically has a single light stripe low on each side. |
Sign, San Diego County park |
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| Feeding |
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Steve Ivie and his Cub Scout troupe saw this snake enter a river in the San Gabriel Mountains of Los Angeles County. They watched the snake swim upstream and grab a trout about 8 or 9 inches in length, then drag the trout onto a rock at the edge of the river, and eat it, as you can see above. © Steve Ivie
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| Habitat |
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Habitat, coastal sage,
San Diego County |
Habitat, desert creek,
San Diego County
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Habitat, San Diego County
mountain meadow |
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Habitat, coastal stream,
San Diego County
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Habitat, San Gabriel Mountains,
Los Angeles County |
Habitat, creek, 5,200 ft., San Gabriel Mountains, Los Angeles County
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Habitat, lake edge, 4,600 ft.
San Diego County |
Habitat, mountain creek,
San Diego County |
Riparian habitat, Ventura County. © Brian Hubbs |
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Habitat, seasonal pond,
San Diego County |
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| Short Video |
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A Two-striped Gartersnake
filmed in San Diego County. |
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Description |
Nonvenomous |
| 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 |
| 24 - 40 inches long (61 - 102 cm). Most often 18 - 30 inches long (46 - 76 cm). Neonates are 7.5 - 9 inches (19 - 23 cm). |
| Appearance |
A medium-sized snake with a head barely wider than the neck and keeled dorsal scales. Appearance is variable - there are two basic pattern morphs. Both have a drab olive, brown, or dark gray ground color, with no dorsal stripe, except for a spot on the neck. The striped morph has a yellowish to gray lateral stripe on each side, and a fairly uniform dorsal coloring, with only faint spotting. The unstriped morph lacks the lateral stripes and has two rows of small dark spots on each side. Light areas between the scales between these spots can create a checkered appearance (as seen in some of the pictures above.) The underside is pale yellow or orange, unmarked, or with dark smudging.
A dark morph is found along the outer coast in San Luis Obispo County. A dark green and a reddish color morph occur along the Piru River in Ventura County. A melanistic population occurs on Catalina Island. |
| Behavior |
Primarily aquatic. Diurnal. Also active at night and at dusk during hot weather in some areas. Can be active from January to November depending on weather conditions.
Most gartersnakes, when picked up, will often strike repeatedly and release cloacal contents and musk. |
| Diet |
| Eats tadpoles, newt larvae, small frogs and toads, fish, and occasionally worms and fish eggs. Probably forages for food in and under water. |
| Reproduction |
| Breeding has been observed in late March and early April, with live young born in late July and August. |
| Range |
| Ranges continuously from near Salinas in Monterey County south along the coast mostly west of the south Coast Ranges, to southern California where it ranges east through the Transverse Ranges (and into the desert in Victorville) and south through the Peninsular Ranges into northern Baja California. Occurs in southern Baja in isolated areas. Also occurs on Catalina Island. At elevations from sea Level to 6,988 ft. (2130 m). |
| Habitat |
| Generally found around pools, creeks, cattle tanks, and other water sources, often in rocky areas, in oak woodland, chaparral, brushland, and coniferous forest. |
| Taxonomic Notes |
Formerly classified as a subspecies of Thamnophis couchii.
T. digueti was synonymized with T. hammondii by McGuire and Grismer (1993, Herpetologica 49:354-365).
The Santa Catalina population of T. hammondii is treated as a distinct subspecies by the California Dept. of Fish and Game - Santa Catalina garter snake, Thamnophis hammondii ssp. |
| Conservation Issues (Conservation Status) |
Protected by the state. Loss of wetland habitats have contributed to a reduction in the range of this snake.
The California Dept. of Fish and Game lists the Santa Catalina garter snake, Thamnophis hammondii ssp. - as a California Species of Special Concern. |
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Taxonomy |
| Family |
Colubridae |
Colubrids |
| Genus |
Thamnophis |
North American Gartersnakes |
Species
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hammondii |
Two-striped Gartersnake |
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Original Description |
Thamnophis hammondii - (Kennicott, 1860) - Proc. Acad. Nat. Sci. Philadelphia, Vol. 12, p. 332
from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
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Meaning of the Scientific Name |
Thamnophis - Greek - thamnos - shrub or bush, and ophis - snake, serpent
hammondii - honors Hammond, William A.
from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
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Alternate Names |
None
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| 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. m. marcianus - Marcy's Checkered Gartersnake
T. ordinoides - Northwestern Gartersnake
T. s. fitchi - Valley Gartersnake
T. s. infernalis - California Red-sided Gartersnake
T. s. tetrataenia - San Francisco Gartersnake
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More Information and References |
Natureserve Explorer
California Dept. of Fish and Game
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.
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The following status listings come from the Special Animals List which is published by the California Department of Fish and Wildlife.
The Special Animals List lists the population on Santa Catalina Island as a separate unnamed subspecies, the Santa Catalina Garter Snake The listings for this species are recorded below in red.
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Organization
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Status Listing
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| U.S. Endangered Species Act (ESA) |
None
None |
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| California Endangered Species Act (CESA) |
None
None |
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| California Department of Fish and Wildlife |
DFG:SSC
None |
California Species of Special Concern |
| Bureau of Land Management |
BLM:
NoneS |
Sensitive |
| USDA Forest Service |
USFS:S
None |
Sensitive |
| Natureserve Global Conservation Status Ranks |
G3 S2
G3T1? S1 |
Vulnerable
Vulnerable |
World Conservation Union - IUCN Red List
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IUCN:L
None C |
Least Concern |
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