Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Natricidae

Scientific Name: Thamnophis ordinoides
Species Authority: (Baird & Girard, 1852)
Common Name(s):
English Northwestern Gartersnake, Northwestern Garter Snake

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Hammerson, G.A.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Listed as Least Concern in view of its relatively wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

Geographic Range [top]

Range Description: This species occurs in southwestern Canada and northwestern United States. Its range includes southwestern British Columbia, western Washington, western Oregon, and extreme northwestern California, including various coastal islands, at elevations from sea level to around 1,680 m (5,500 feet) (Nussbaum et al. 1981, Brown et al. 1995, Rossman et al. 1996, Ernst and Ernst 2003, Stebbins 2003).
Countries occurrence:
Canada; 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) (see dot map in Nussbaum et al. 1981). The adult population size is unknown but certainly exceeds 100,000. This snake is common in many parts of its range. Its extent of occurrence, area of occupancy, number of subpopulations, and population size are probably relatively stable.
Current Population Trend: Stable
Additional data:

Habitat and Ecology [top]

Habitat and Ecology: This snake is primarily terrestrial but may be found near or occasionally in water; often it occurs in meadows, forest clearings, and along the edges of thickets (Nussbaum et al. 1983, Brown et al. 1995, Rossman et al. 1996, Ernst and Ernst 2003, Stebbins 2003). Hibernation sites include talus slopes or deep rock crevices.
Systems: Terrestrial

Threats [top]

Major Threat(s): No major threats are known.

Conservation Actions [top]

Conservation Actions: Many occurrences are in protected areas.

Classifications [top]

1. Forest -> 1.4. Forest - Temperate
suitability: Suitable  
3. Shrubland -> 3.4. Shrubland - Temperate
suitability: Suitable  
4. Grassland -> 4.4. Grassland - Temperate
suitability: Suitable  
5. Wetlands (inland) -> 5.4. Wetlands (inland) - Bogs, Marshes, Swamps, Fens, Peatlands
suitability: Marginal  
14. Artificial/Terrestrial -> 14.4. Artificial/Terrestrial - Rural Gardens
suitability: Marginal  

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education

Bibliography [top]

Brown, H.A., Bury, R.B., Darda, D.M., Diller, L.V., Peterson, C.R. and Storm, R.M. 1995. Reptiles of Washington and Oregon. Seattle Audubon Society, Seattle, Washington. viii + 176pp.

Ernst, C.H. and Ernst, E.M. 2003. Snakes of the United States and Canada. Smithsonian Books, Washington, D.C.

IUCN. 2007. 2007 IUCN Red List of Threatened Species. Available at: (Accessed: 12th September 2007).

Nussbaum, R.A., Brodie Jr., E.D. and Storm, R.M. 1983. Amphibians and Reptiles of the Pacific Northwest. University Press of Idaho. 332 pp.

Rossman, D.A., Ford, N.B. and Seigel, R.A. 1996. The Garter Snakes. University of Oklahoma Press, Norman, Oklahoma and London, UK.

Stebbins, R.C. 2003. A Field Guide to Western Reptiles and Amphibians. Third Edition. Houghton Mifflin Company, Boston, Massachusetts.

Citation: Hammerson, G.A. 2007. Thamnophis ordinoides. The IUCN Red List of Threatened Species 2007: e.T63985A12726329. . Downloaded on 13 October 2015.
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