Thamnophis sirtalis

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	REPTILIA	SQUAMATA	NATRICIDAE

Scientific Name:

Thamnophis sirtalis

Species Authority:

(Linnaeus, 1758)

Common Name/s:

English

–

San Francisco Garter Snake

Assessment Information [top]

Red List Category & Criteria:	Least Concern ver 3.1
Year Published:	2007
Assessor/s:	Frost, D.R., Hammerson, G.A. & Santos-Barrera, G.
Reviewer/s:	Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Contributor/s:
Justification: Listed as Least Concern in view of its extremely wide distribution, presumed large population, and because populations are unlikely to be declining.

Geographic Range [top]

Range Description:	The species' wide range includes much of North America, from southeastern Alaska, British Columbia, southern Northwest Territories, northern Saskatchewan, central Manitoba, Ontario, central Quebec, and the Maritime Provinces of Canada, to southern California, central Utah, northeastern Colorado, New Mexico, and Chihuahua (Mexico) (disjunct), Texas, Gulf Coast, and southern Florida (Conant and Collins 1991, Ernst and Ernst 2003, Stebbins 2003). There is a very small population in northwestern Chihuaha, Mexico.
Countries:	Native: Mexico; United States
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	This species is represented by a very large number of occurrences (subpopulations) (Fitch 1980). Many occurrences have good viability. The total adult population size is unknown but probably exceeds 1,000,000. Long-term extent of occurrence, area of occupancy, number of subpopulations, and population size have probably been relatively stable. Currently, extent of occurrence, area of occupancy, number of subpopulations, and population size are probably relatively stable or declining at a low rate.
Population Trend:	Stable

Population:

This species is represented by a very large number of occurrences (subpopulations) (Fitch 1980). Many occurrences have good viability. The total adult population size is unknown but probably exceeds 1,000,000. Long-term extent of occurrence, area of occupancy, number of subpopulations, and population size have probably been relatively stable. Currently, extent of occurrence, area of occupancy, number of subpopulations, and population size are probably relatively stable or declining at a low rate.

Population Trend:

Stable

Habitat and Ecology [top]

Habitat and Ecology:	Throughout the range, this species inhabits a very wide range of aquatic, wetland, and upland habitats; habitat preference exhibits rather pronounced regional differences (e.g., east vs. west). When inactive, it occurs underground, in or under surface cover, or in other secluded sites.
Systems:	Terrestrial; Freshwater

Threats [top]

Major Threat(s):	No major threats have been identified. The Mexican population is vulnerable to changes in hydrology.

Major Threat(s):

No major threats have been identified. The Mexican population is vulnerable to changes in hydrology.

Conservation Actions [top]

Conservation Actions:	Many occurrences of this species are in areas that afford adequate protection.

Conservation Actions:

Many occurrences of this species are in areas that afford adequate protection.

Citation:	Frost, D.R., Hammerson, G.A. & Santos-Barrera, G. 2007. Thamnophis sirtalis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.
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