Two-striped garter snake (Thamnophis hammondii)
The two-striped garter snake is a snake in the family Colubridae with a mild venom for its prey, not dangerous to people. GBIF holds 1,622 licensed U.S. records of it; it reaches our listing threshold in 1 state, most of all California (1,620). Its observation records peak in May.
The two-striped garter snake (Thamnophis hammondii) is a species of aquatic snake in the subfamily Natricinae of the family Colubridae. The species is endemic to western North America.
From Wikipedia: Two-striped garter snake, text under CC BY-SA 4.0.
Is the two-striped garter snake poisonous or venomous?
Mildly venomous but not dangerous: the two-striped 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 two-striped garter snake?
All listed records come from a single state, California, with 1,620 records.
| # | State | Records | Share of state snakes | Rank in state |
|---|---|---|---|---|
| 1 | California | 1,620 | 2.2% | 10th of 46 |
When is the two-striped garter snake seen?
Across the U.S., observation records of the two-striped garter snake run mostly March through August, peaking in May with 25% of them. Winter (December to February) holds 2% of them.
How recent are the two-striped garter snake records?
The two-striped garter snake record leans on older material: only 11% of dated U.S. records come from 2017–2026, and the median record is from 1975. The oldest dated record is from 1861; the busiest year was 1938, with 144 records.
| Decade | Records | Share |
|---|---|---|
| 1860s | 2 | 0.1% |
| 1870s | 3 | 0.2% |
| 1880s | 3 | 0.2% |
| 1890s | 30 | 1.9% |
| 1900s | 28 | 1.8% |
| 1910s | 68 | 4.4% |
| 1920s | 155 | 10.1% |
| 1930s | 219 | 14.2% |
| 1940s | 71 | 4.6% |
| 1950s | 37 | 2.4% |
| 1960s | 66 | 4.3% |
| 1970s | 312 | 20.3% |
| 1980s | 191 | 12.4% |
| 1990s | 48 | 3.1% |
| 2000s | 106 | 6.9% |
| 2010s | 57 | 3.7% |
| 2020s | 144 | 9.4% |
Species recorded in the same counties
Of the 15 counties where the two-striped garter snake is most recorded, 15 are also top counties for each of the first three snakes in the table below; no other snake shares more. Venomous species among its neighbors: the western rattlesnake.
| Species | Shared counties |
|---|---|
| California kingsnake | 15 |
| Gopher snake | 15 |
| Western rattlesnake venomous | 15 |
| Coachwhip | 12 |
| Striped racer | 12 |
| Coast nightsnake | 11 |
| Glossy snake | 11 |
| Long-nosed snake | 10 |
Related species in the U.S.
Other species of the genus Thamnophis with profiles here: Western terrestrial garter snake, Common garter snake, Western ribbon snake, Aquatic garter snake, Northwestern garter snake, Western aquatic garter snake, Plains garter snake and Checkered garter snake.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.