BC Conservation Data Centre: Species Summary
Thamnophis ordinoides
Northwestern Gartersnake
| Scientific Name: | Thamnophis ordinoides (Baird and Girard, 1852) | ||||||||||
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| English Name: | Northwestern Gartersnake | ||||||||||
| English Name Synonyms: |
Northwestern Garter Snake
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| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | Rossman, D. A., N. B. Ford, and R. A. Seigel. 1996. The garter snakes: evolution and ecology. University of Oklahoma Press, Norman. xx + 332 pp. | ||||||||||
| Classification Level: | Species | ||||||||||
| Species Group: | Vertebrate Animal | ||||||||||
| Species Code: | R-THOR | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G5 (Feb 2016) | ||||||||||
| Provincial Status: | S5 (Mar 2025) | ||||||||||
| BC List: | Yellow | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Not at Risk (May 2003) | ||||||||||
| SARA Schedule: | |||||||||||
| General Status Canada: | 4 - Secure (2005) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Global Reproduction Comments: | Copulates usually in the spring, less commonly in the fall (Nussbaum et al. 1983). Viviparous. Parturition occurs in summer or early fall. Litter size generally less than 20. | ||||||||||
| Migration Characteristics: (Global / Provincial) | |||||||||||
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Nonmigrant: Local Migrant: Distant Migrant: Within Borders Migrant: |
Y / Y / N / na / |
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| Habitats: (Type / Subtype / Dependence) |
Agriculture / Cultivated Field / Unknown
Agriculture / Hedgerow / Unknown Agriculture / Pasture/Old Field / Unknown Anthropogenic / Industrial / Facultative - frequent use Anthropogenic / Urban/Suburban / Facultative - frequent use Grassland/Shrub / Meadow / Facultative - frequent use Grassland/Shrub / Shrub - Logged / Unknown Grassland/Shrub / Shrub - Natural / Unknown Riparian / Riparian Shrub / Facultative - frequent use Rock/Sparsely Vegetated Rock / Talus / Obligate Subterranean / Caves / Obligate Subterranean / Sub-soil / Obligate |
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| Global Habitat Comments: | 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. | ||||||||||
| Food Habits: |
Carnivore: Adult, Immature
Invertivore: Adult, Immature |
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| Global Food Habits Comments: | Feeds mainly on slugs as well as worms, salamanders and frogs. | ||||||||||
| Global Phenology: |
Diurnal: Adult, Immature
Hibernates/aestivates: Adult, Immature |
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| Global Phenology Comments: | Inactive in cold temperatures. Most active on sunny days. | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
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| Colonial Breeder: | N | ||||||||||
| Length(cm)/width(cm)/Weight(g): | 66/ / | ||||||||||
| Elevation (m) (min / max): |
Global:
Provincial: |
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| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | The 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 meters (5,500 feet) (Nussbaum et al. 1981, Brown et al. 1995, Rossman et al. 1996, Ernst and Ernst 2003, Stebbins 2003). | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | Hammerson, G. | ||||||||||
| Last Updated: | Sep 07, 2006 | ||||||||||
| Provincial Information Author: | |||||||||||
| Last Updated: | |||||||||||
| References and Related Literature | |||||||||||
Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp. |
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Brown, H. A., R. B. Bury, D. M. Darda, L. V. Diller, C. R. Peterson, and R. M. Storm. 1995. Reptiles of Washington and Oregon. Seattle Audubon Society, Seattle, Washington. viii + 176 pp. |
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Kirk, J.J. 1979. Thamnophis ordinoides. Cat. Am. Amph. Rep. 233.1-233.2. |
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Nussbaum, R.A., E.D. Brodie, Jr., and R.M. Storm. 1983. Amphibians and Reptiles of the Pacific Northwest. University Press of Idaho, Moscow, Idaho. 332 pp. |
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Ovaska, K, S. Lennart, C Engelstoft, L. Matthias, E. Wind and J. MacGarvie. 2004. Best Management Practices for Amphibians and Reptiles in Urban and Rural Environments in British Columbia. Ministry of Water Land and Air Protection, Ecosystems Standards and Planning, Biodiversity Branch |
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Ovaska, K., and C. Engelstoft. 2003. Attracting Snakes into your Backyard - tips for reptile-friendly landscaping and gardening. Can. Habitat Stewardship Program, Habitat Conservation Trust Fund, and B.C. Minist. Water, Land and Air Prot. 4pp. |
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Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp. |
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The Reptiles of British Columbia: Northwestern Garter Snake, Thamnophis ordinoides. 2004. Univ. Coll. of the Cariboo, and B.C. Minist. Water, Land and Air Prot. Online. Available: http://www.bcreptiles.ca/snakes/nw_garter.htm |
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Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. 2006. Species Summary: Thamnophis ordinoides. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 13, 2026).