Thamnophis elegans

The species' range extends from central British Columbia, central Alberta, and southwestern Manitoba in Canada, south through all of the western United States (east to western South Dakota, western Nebraska, Colorado, extreme western Oklahoma, and New Mexico) to (disjunctly) northern Baja California. There are many isolated populations around the margins of the main range (Fitch 1983, Rossman et al. 1996, Grismer 2002, Stebbins 2003), notably in the Sierra Nevada and San Bernardino Mountains of California, and Sierra San Pedro Martir in Baja California (subspecies T. c. hueyi). Its elevational range extends from sea level to 3,995 m asl (13,100 feet) (very rarely); usually below 3,355 m asl (11,000 feet) (Hammerson 1999, Stebbins 2003).

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) The range extends from central British Columbia, central Alberta, and southwestern Manitoba south through all of the western United States (east to western South Dakota, western Nebraska, Colorado, extreme western Oklahoma, and New Mexico) to (disjunctly) northern Baja California (Sierra San Pedro Martir), with many isolated populations around the margins of the main range (Fitch 1983, Rossman et al. 1996, Grismer 2002, Stebbins 2003). Elevational range extends from sea level to 11,000 feet (3,355 meters), or higher in some locations (Hammerson 1999, Stebbins 2003).

Continent: Middle-America North-America
Distribution: W USA (Washington, Oregon, Montana), SW Canada,  Mexico (Baja California Norte)  Has been found in 3990 m elevation.  vagrans: W USA (Washington, Nevada, NW New Mexico), W Canada (British Columbia, Saskatchewan, Alberta)

Length: 107 cm

Habitat and Ecology

Systems

• Terrestrial
• Freshwater

Comments: This species occurs in a wide variety of habitats, from lowlands to high mountains: grassland, shrubland, woodland, and open areas in forests. It is chiefly terrestrial in most areas, but also aquatic in some locations (e.g., high Sierra Nevada). Often it inhabits wetlands and areas near streams, ponds, and lakes.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Comments: Feeds on slugs, worms, snails, leeches, tadpoles, frogs, fish, mice, and occasionally small birds. Also eats insects, and carrion. Some forms capture prey in water, others feed entirely terrestrially (Nussbaum et al. 1983). Depends on amphibians in the high Sierra Nevada, California (Jennings et al. 1992).

At least in some parts of the range of this snake, the rear upper jaw teeth are relatively long and bladelike and apparently function in impaling, holding, and manipulating the prey. The snakes salivary secretions aid in breaking down prey tissues.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: This species is represented by hundreds of occurrences or subpopulations (e.g., see maps in Fitch 1983, Degenhardt et al. 1996, and Hammerson 1999).

100,000 to >1,000,000 individuals

Comments: Total adult population size is unknown but certainly exceeds 100,000. This snake is very common in many areas.

Comments: This snake is inactive during cold winter weather; the duration of the inactive period varies with the local climate. In most areas, activity occurs from March-April to October-November.

Maximum longevity: 17.8 years (captivity) Observations: Reproductive success appears to increase with age in these animals, suggesting increasing fecundity with age (Sparkman et al. 2007).

Courtship and mating occur primarily in spring, soon after emergence from hibernation, though late summer sexual activity has been observed in some parts of the range. In the mountains, newborn individuals first appear most often in August and early September; at lower elevations births sometimes occurs as early as mid-July. Litter size usually is fewer than 20.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 3
Species With Barcodes: 1

Year Assessed

Assessor/s

Reviewer/s

Justification

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Intrinsic Vulnerability: Not intrinsically vulnerable

Population

Population Trend

Global Short Term Trend: Relatively stable (=10% change)

Comments: Extent of occurrence, area of occupancy, number of subpopulations, and population size probably are relatively stable.

Global Long Term Trend: Increase of 10-25% to decline of 30%

Degree of Threat: Low

Comments: No major threats are known. In high-elevation areas of the southern Sierra Nevada in California, introductions of non-native trout apparently have led to declines in populations of amphibians and possibly also of T. elegans, which may depend on amphibians as a primary food resource (and which may occasionally serve as prey for trout) (Matthews et al. 2002). However, Matthews et al. (2002) did not discuss the historical distribution of T. elegans in their study areas, so the significance of extensive trout introductions in the absence of garter snakes from some areas (John Muir Wilderness) is uncertain. Further study is warranted (e.g., in the mountains of Colorado, T. elegans is a versatile feeder [Hammerson 1999], and garter snake populations may not rely strongly on amphibian populations).

Major Threats

Conservation Actions

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: Many occurrences are in protected areas.