A Guide to the Amphibians
and Reptiles of California


Key to
California Gartersnakes

California Gartersnakes
Upper Labial Scales Comparison



Snake Number of
Upper Labial Scales
 
Thamnophis atratus atratus

Santa Cruz Gartersnake
8

6 and 7 not enlarged

(7th longer than 6th)
gartersnake
Thamnophis atratus hydrophilus

Oregon Gartersnake
8

6 and 7 not enlarged
(7th longer than 6th)
gartersnake
Thamnophis atratus zaxanthus

Diablo Range Gartersnake

8

6 and 7 not enlarged
(7th longer than 6th)
gartersnake
Thamnophis couchii

Sierra Gartersnake
8

6th is wider
than 7th

gartersnake
Thamnophis elegans elegans

Mountain Gartersnake
8

Occasionally 7
6 and 7
are enlarged, higher than wide

gartersnake
Thamnophis elegans terrestris

Coast Gartersnake
8

Occasionally 7
6 and 7
are enlarged, higher than wide

gartersnake
Thamnophis elegans vagrans

Wandering Gartersnake
8

Occasionally 7
6 and 7
are enlarged, higher than wide

gartersnake
Thamnophis gigas

Giant Gartersnake
8

6th is shorter than 7th

gartersnake
Thamnophis hammondii

Two-striped Gartersnake
8
gartersnake
Thamnophis marcianus

Marcy's Checkered Gartersnake
8
gartersnake
Thamnophis ordinoides

Northwestern Gartersnake
7

Sometimes 8,
rarely 6

gartersnake
Thamnophis sirtalis fitchi

Valley Gartersnake
Usually 7
Occasionally 8, rarely 6 or 9

Often with
black wedges
gartersnake
Thamnophis sirtalis infernalis

California Red-sided Gartersnake


(and South Coast Gartersnake)
Usually 7
Occasionally 8, rarely 6 or 9

Often with
black wedges
gartersnake
Thamnophis sirtalis tetrataenia

San Francisco Gartersnake
Usually 7
Occasionally 8, rarely 6 or 9

Often with
black wedges
gartersnake
Snake Number of
Upper Labial Scales
 
 

Useful Comparisons of Sometimes Similar Species

Thamnophis atratus gartersnake
Thamnophis elegans gartersnake
Thamnophis sirtalis gartersnake
Thamnophis ordinoides gartersnake
 





References


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.

St. John, Alan D. Reptiles of the Northwest: Alaska to California; Rockies to the Coast. Lone Pine Publishing, 2002.

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

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

Brown et. al. Reptiles of Washington and Oregon. Seattle Audubon Society, 1995.













































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