Western terrestrial garter snake (Thamnophis elegans)
The western terrestrial garter snake is a snake in the family Colubridae with a mild venom for its prey, not dangerous to people. GBIF holds 30,339 licensed U.S. records of it; it reaches our listing threshold in 13 states, most of all California (21,830), Oregon (1,814) and Utah (1,224). Its observation records peak in July.
The western terrestrial garter snake (Thamnophis elegans) is a western North American species of colubrid snake. At least five subspecies are recognized.
From Wikipedia: Western terrestrial garter snake, text under CC BY-SA 4.0.
Is the western terrestrial garter snake poisonous or venomous?
Mildly venomous but not dangerous: the western terrestrial garter snake has enlarged rear teeth and a mild venom for its prey, and a bite causes at most local swelling, which is why many sources simply call it harmless. It is not a pit viper or coral snake, the only U.S. land snakes with medically dangerous venom. Clean any bite like a small wound.
Which states have the western terrestrial garter snake?
The western terrestrial garter snake's U.S. record is concentrated: California alone holds 72% of licensed records. It is listed in 13 states in all; the next are Oregon (1,814), Utah (1,224) and Colorado (835).
| # | State | Records | Share of state snakes | Rank in state |
|---|---|---|---|---|
| 1 | California | 21,830 | 29.7% | 1st of 46 |
| 2 | Oregon | 1,814 | 23.9% | 3rd of 16 |
| 3 | Utah | 1,224 | 36.8% | 1st of 28 |
| 4 | Colorado | 835 | 24.0% | 2nd of 26 |
| 5 | Arizona | 728 | 3.5% | 8th of 60 |
| 6 | New Mexico | 656 | 10.2% | 3rd of 56 |
| 7 | Idaho | 616 | 41.8% | 1st of 11 |
| 8 | South Dakota | 590 | 18.5% | 2nd of 16 |
| 9 | Nevada | 557 | 13.8% | 2nd of 27 |
| 10 | Washington | 535 | 10.1% | 4th of 11 |
| 11 | Wyoming | 505 | 47.6% | 1st of 11 |
| 12 | Montana | 421 | 32.9% | 1st of 9 |
| 13 | Nebraska | 18 | 0.8% | 20th of 31 |
When is the western terrestrial garter snake seen?
Across the U.S., observation records of the western terrestrial garter snake run mostly April through October, peaking in July with 18% of them. Winter (December to February) holds 2% of them.
Season by state
Among states whose main season falls within one calendar year, it starts earliest in March (California) and latest in May (Colorado, Montana, New Mexico, Oregon and Wyoming). The most common peak month is July, shared by Colorado, Montana, New Mexico and Wyoming.
| State | Main season | Peak month | Observation records |
|---|---|---|---|
| California | March through October | April | 721 |
| Colorado | May through October | July | 400 |
| Utah | April through September | May | 210 |
| Idaho | April through October | June | 152 |
| New Mexico | May through October | July | 130 |
| Montana | May through September | July | 119 |
| Oregon | May through September | June | 82 |
| Wyoming | May through September | July | 80 |
| Arizona | April through October | June | 70 |
| Washington | April through September | April | 45 |
Where the western terrestrial garter snake is recorded in each state
California
California holds 21,830 licensed records, the most recorded of 46 snakes listed there. Its observation records in California run mostly March through October, peaking in April; most licensed records come from Lassen County, Shasta County and Humboldt County. Next come Sonoma County (1,518) and Santa Cruz County (1,017).
Oregon
Oregon holds 1,814 licensed records, the 3rd most recorded of 16 snakes listed there. Its observation records in Oregon run mostly May through September, peaking in June; most licensed records come from Jackson County, Klamath County and Washington County. Next come Lake County (71) and Grant County (38).
Utah
Utah holds 1,224 licensed records, the most recorded of 28 snakes listed there. Its observation records in Utah run mostly April through September, peaking in May; most licensed records come from Utah County, Salt Lake County and San Juan County. Next come Sanpete County (111) and Garfield County (108).
Colorado
Colorado holds 835 licensed records, the 2nd most recorded of 26 snakes listed there. Its observation records in Colorado run mostly May through October, peaking in July; most licensed records come from Gunnison County, Larimer County and Boulder County. Next come El Paso County (60) and La Plata County (51).
Arizona
Arizona holds 728 licensed records, the 8th most recorded of 60 snakes listed there. Its observation records in Arizona run mostly April through October, peaking in June; most licensed records come from Coconino County, Apache County and Gila County. Next come Graham County (42) and Yavapai County (33).
New Mexico
New Mexico holds 656 licensed records, the 3rd most recorded of 56 snakes listed there. Its observation records in New Mexico run mostly May through October, peaking in July; most licensed records come from Rio Arriba County, Catron County and Lincoln County. Next come Otero County (65) and Colfax County (37).
Idaho
Idaho holds 616 licensed records, the most recorded of 11 snakes listed there. Its observation records in Idaho run mostly April through October, peaking in June; most licensed records come from Bonneville County, Ada County and Bingham County. Next come Blaine County (52) and Caribou County (45).
South Dakota
South Dakota holds 590 licensed records, the 2nd most recorded of 16 snakes listed there. Most of its licensed records in South Dakota come from Pennington County, Butte County and Custer County. Next come Lawrence County (37) and Meade County (3).
Nevada
Nevada holds 557 licensed records, the 2nd most recorded of 27 snakes listed there. Most of its licensed records in Nevada come from Washoe County, Elko County and White Pine County. Next come Humboldt County (37) and Nye County (31).
Washington
Washington holds 535 licensed records, the 4th most recorded of 11 snakes listed there. Its observation records in Washington run mostly April through September, peaking in April; most licensed records come from Pierce County, Thurston County and Mason County. Next come San Juan County (45) and Walla Walla County (27).
Wyoming
Wyoming holds 505 licensed records, the most recorded of 11 snakes listed there. Its observation records in Wyoming run mostly May through September, peaking in July; most licensed records come from Carbon County, Teton County and Albany County. Next come Park County (41) and Lincoln County (18).
Montana
Montana holds 421 licensed records, the most recorded of 9 snakes listed there. Its observation records in Montana run mostly May through September, peaking in July; most licensed records come from Sanders County, Lake County and Missoula County. Next come Ravalli County (28) and Yellowstone County (27).
Top counties in the U.S.
| # | County | State | Records | Share of U.S. |
|---|---|---|---|---|
| 1 | Lassen County | California | 6,630 | 21.9% |
| 2 | Shasta County | California | 4,014 | 13.2% |
| 3 | Humboldt County | California | 2,828 | 9.3% |
| 4 | Sonoma County | California | 1,518 | 5.0% |
| 5 | Santa Cruz County | California | 1,017 | 3.4% |
| 6 | Jackson County | Oregon | 855 | 2.8% |
| 7 | San Mateo County | California | 770 | 2.5% |
| 8 | Siskiyou County | California | 735 | 2.4% |
| 9 | Mono County | California | 547 | 1.8% |
| 10 | Klamath County | Oregon | 466 | 1.5% |
| 11 | Marin County | California | 382 | 1.3% |
| 12 | Monterey County | California | 374 | 1.2% |
| 13 | Coconino County | Arizona | 362 | 1.2% |
| 14 | San Francisco County | California | 297 | 1.0% |
| 15 | Pennington County | South Dakota | 251 | 0.8% |
How recent are the western terrestrial garter snake records?
The western terrestrial garter snake record leans on older material: only 6% of dated U.S. records come from 2017–2026, and the median record is from 1984. The oldest dated record is from 1856; the busiest year was 1982, with 2,139 records.
| Decade | Records | Share |
|---|---|---|
| 1850s | 5 | 0.0% |
| 1860s | 9 | 0.0% |
| 1870s | 57 | 0.2% |
| 1880s | 23 | 0.1% |
| 1890s | 166 | 0.5% |
| 1900s | 409 | 1.3% |
| 1910s | 637 | 2.0% |
| 1920s | 298 | 0.9% |
| 1930s | 949 | 3.0% |
| 1940s | 1,577 | 4.9% |
| 1950s | 488 | 1.5% |
| 1960s | 727 | 2.3% |
| 1970s | 5,997 | 18.8% |
| 1980s | 9,137 | 28.6% |
| 1990s | 2,347 | 7.3% |
| 2000s | 6,503 | 20.3% |
| 2010s | 1,054 | 3.3% |
| 2020s | 1,592 | 5.0% |
Species recorded in the same counties
Of the 167 counties where the western terrestrial garter snake is most recorded, 118 are also top counties for the gopher snake, more than for any other snake. Venomous species among its neighbors: the western rattlesnake and the prairie rattlesnake.
| Species | Shared counties |
|---|---|
| Gopher snake | 118 |
| Western rattlesnake venomous | 73 |
| Common garter snake | 72 |
| Eastern racer | 72 |
| Northern rubber boa | 56 |
| Prairie rattlesnake venomous | 54 |
| Striped whipsnake | 48 |
| California kingsnake | 33 |
Related species in the U.S.
Other species of the genus Thamnophis with profiles here: Common garter snake, Western ribbon snake, Aquatic garter snake, Northwestern garter snake, Western aquatic garter snake, Plains garter snake, Checkered garter snake and Eastern ribbonsnake.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.