California Reptiles & Amphibians

Thamnophis hammondii - Two-striped Gartersnake



Click on a picture for a larger view




Range in California: Red




Young adult, spotted morph, Cottonwood Creek, San Diego County
Adult, striped morph, Santa Barbara County © Brian Hubbs
Adult, San Diego County
Adult, Ventura County © Patrick Briggs
Adult, spotted morph (with faint stripes), Laguna Mountains,
San Diego County © John Stoklosa
Adult, Ventura County © Jeremy Huff
Steve Ivie and his Cub Scout troup watched this snake enter river in the San Gabriel Mountains where it swam upstream and grabbed an 8 to 9 inch trout. The snake dragged the fish up onto a rock, subdued it, then ate it. © Steve Ivie
Habitat, coastal sage, San Diego County
Habitat, San Diego County mountain meadow
Habitat, desert creek, San Diego County
Habitat, coastal river, San Diego County
Habitat, San Gabriel Mountains,
Los Angeles County
Sign, San Diego County Park
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.

Taxonomy
Family Colubridae Colubrids
Genus Thamnophis North American Gartersnakes
Species


hammondii Two-striped Gartersnake
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

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

Alternate Names
None

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

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. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Bartlett, R.D. , & Alan Tennant. Snakes of North America - Western Region. Gulf Publishing Co., 2000.

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.

Brown, Philip R. A Field Guide to Snakes of California. Gulf Publishing Co., 1997.

Conservation Status

The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.


Organization
Status Listing
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Game DFG:SSC California Species of Special Concern
Bureau of Land Management BLM:S Sensitive
USDA Forest Service USFS:S Sensitive
Natureserve Global Conservation Status Ranks G3 Vulnerable
World Conservation Union - IUCN Red List




IUCN:DD Data Deficient

 

Home | Lists | Maps | Photo Indexes | Sounds | Identification | More Info | Beyond CA | About Us | Usage | Taxonomy | New Stuff | Thanks | Disclaimers | Contact

Return to the Top                     © 2000 - 2008