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Reptilia    Squamata (part-snakes)    Natricidae  
Two-striped Gartersnake
Thamnophis hammondii (Kennicott, 1860)
THAM-noh-fiss — HAM-mond-ee-eye
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SSAR 9th Edition Comments:
 There are no current SSAR comments for this taxon.

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Open icons indicate questionable records, including those with coordinate uncertainty greater than 10,000 m (approximately 6 miles). Click a marker to view metadata.
Occurrences:; 5,011 Total; 2,829 Museum; 2,182 Other

The locality database contains 8,094,850 records, and geographic and taxonomic errors exist. Logged-in, registered users may report a potential issue directly from the marker popup.
Shaded range maps are based on curated specimens and provided gratis by CNAH. (Version: 2025.06.25.15.23.13)
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Province/State Distribution:
United States: California

Taxonomic Etymology:
Named for a 19th-century naturalist.
Thamnophis — From Greek thamnos (θάμνος), “bush” or “shrub,” and ophis (ὄφις), “snake.” The name means “bush-snake” or “shrub-snake,” likely referring to the habitats where these snakes are commonly found.
hammondii — A patronym honoring Dr. William A. Hammond (1828–1900), U.S. Army surgeon and field collector.

First instance(s) of published English names:
Hammond's Garter Snake (Eutaenia hammondii: Cooper, James G. 1869. The fauna of California and its geographical distribution. Proceedings of the California Academy of Sciences, 1st Series 4():61-81); Hammond's Garter Snake (Eutaenia hammondi: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Califronian Garter Snake (Thamnophis hammondii: Van Denburgh, John. 1897. The reptiles of the Pacific Coast and Great Basin: An account of the species known to inhabit California, and Oregon, Washington, Idaho, and Nevada. Occasional Papers of the California Academy of Sciences 5():9-236); Californian Garter Snake (Thamnophis hammondii: Van Denburgh, John. 1897. The reptiles of the Pacific Coast and Great Basin: An account of the species known to inhabit California, and Oregon, Washington, Idaho, and Nevada. Occasional Papers of the California Academy of Sciences 5():9-236); California Garter Snake (Thamnophis ordinoides hammondii: Van Denburgh, John. 1922. The Reptiles of Western North America: An Account of the Species Known to Inhabit California and Oregon, Washinton, Idaho, Utah, Nevada, Arizona, British Columbia, Sonora, and Lower California. Volume I. Lizards. California Academy of Sciences, San Francisco. 556pp.); Two-striped Garter Snake (Thamnophis hammondii: Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.); Two-striped Garter Snake (Thamnophis elegans hammondi: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.);


Selected References:
1860 Kennicott, Robert. Descriptions of new species of North American serpents in the Museum of the Smithsonian Institution, Washington. Proceedings of the Academy of Natural Sciences of Philadelphia 12:328-338
1903 Brown, Arthur Edwin. The variations of Eutaenia in the Pacific subregion. Proceedings of the Academy of Natural Sciences of Philadelphia 55:286-297
1908 Ruthven, Alexander G. Variations and genetic relationships of the garter-snakes. Bulletin of the United States National Museum (61):1-201
1985 Lawson, Robin. Molecular studies of Thamnophiine snakes. Dissertation. Louisiana State University, Baton Rouge. 191pp.
1993 McGuire, Jimmy A. and L. Lee Grismer. The taxonomy and biogeography of Thamnophis hammondii and T. digueti (Reptilia: Squamata: Colubridae) in Baja California, Mexico. Herpetologica 49(3):354-365
2002 Queiroz, de, Alan, Robin Lawson, and Julio A. Lemos-Espinal. Phylogenetic relationships of North American garter snakes (Thamnophis) based on four mitochondrial genes: How much DNA sequence is enough? Molecular Phylogenetics and Evolution 22(2):315-329

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