Shorthead garter snake (Thamnophis brachystoma)
The shorthead garter snake is a snake in the family Colubridae with a mild venom for its prey, not dangerous to people. GBIF holds 614 licensed U.S. records of it; it reaches our listing threshold in 3 states, most of all Pennsylvania (523), New York (89) and Ohio (2).
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Thamnophis brachystoma, commonly known as the shorthead garter snake or short-headed gartersnake, is a small species of snake in the subfamily Natricinae of the family Colubridae. The species is native to the northeastern United States.
From Wikipedia: Shorthead garter snake, text under CC BY-SA 4.0.
Is the shorthead garter snake poisonous or venomous?
Mildly venomous but not dangerous: the shorthead 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 shorthead garter snake?
The shorthead garter snake's U.S. record is concentrated: Pennsylvania alone holds 85% of licensed records. It is listed in 3 states in all; the next are New York (89) and Ohio (2).
| # | State | Records | Share of state snakes | Rank in state |
|---|---|---|---|---|
| 1 | Pennsylvania | 523 | 6.2% | 5th of 20 |
| 2 | New York | 89 | 1.5% | 12th of 17 |
| 3 | Ohio | 2 | 0.0% | 25th of 25 |
Where the shorthead garter snake is recorded in each state
Pennsylvania
Pennsylvania holds 523 licensed records, the 5th most recorded of 20 snakes listed there. Most of its licensed records in Pennsylvania come from Warren County, Clarion County and Forest County. Next come Venango County (42) and McKean County (27).
New York
New York holds 89 licensed records, the joint 12th most recorded of 17 snakes listed there. Most of its licensed records in New York come from Cattaraugus County, Chemung County and Chautauqua County. Next come Erie County (2) and Allegany County (2).
Top counties in the U.S.
| # | County | State | Records | Share of U.S. |
|---|---|---|---|---|
| 1 | Warren County | Pennsylvania | 208 | 33.9% |
| 2 | Clarion County | Pennsylvania | 74 | 12.1% |
| 3 | Forest County | Pennsylvania | 73 | 11.9% |
| 4 | Cattaraugus County | New York | 46 | 7.5% |
| 5 | Venango County | Pennsylvania | 42 | 6.8% |
| 6 | McKean County | Pennsylvania | 27 | 4.4% |
| 7 | Jefferson County | Pennsylvania | 26 | 4.2% |
| 8 | Chemung County | New York | 25 | 4.1% |
| 9 | Crawford County | Pennsylvania | 16 | 2.6% |
| 10 | Erie County | Pennsylvania | 16 | 2.6% |
| 11 | Chautauqua County | New York | 13 | 2.1% |
| 12 | Clearfield County | Pennsylvania | 12 | 2.0% |
| 13 | Allegheny County | Pennsylvania | 8 | 1.3% |
| 14 | Elk County | Pennsylvania | 7 | 1.1% |
| 15 | Mercer County | Pennsylvania | 7 | 1.1% |
How recent are the shorthead garter snake records?
The shorthead garter snake record leans on older material: only 3% of dated U.S. records come from 2016–2025, and the median record is from 1953. The oldest dated record is from 1860; the busiest year was 1947, with 129 records.
| Decade | Records | Share |
|---|---|---|
| 1860s | 1 | 0.2% |
| 1920s | 1 | 0.2% |
| 1930s | 17 | 2.7% |
| 1940s | 227 | 36.6% |
| 1950s | 131 | 21.1% |
| 1960s | 62 | 10.0% |
| 1970s | 52 | 8.4% |
| 1980s | 81 | 13.1% |
| 1990s | 17 | 2.7% |
| 2000s | 12 | 1.9% |
| 2010s | 1 | 0.2% |
| 2020s | 18 | 2.9% |
Species recorded in the same counties
Of the 21 counties where the shorthead garter snake is most recorded, 13 are also top counties for the red-bellied snake, more than for any other snake. None of its closest neighbors is venomous.
| Species | Shared counties |
|---|---|
| Red-bellied snake | 13 |
| DeKay's brown snake | 11 |
| Smooth green snake | 10 |
| Northern water snake | 9 |
| Ring-necked snake | 9 |
| Eastern milksnake | 8 |
| Common garter snake | 7 |
| Eastern ribbonsnake | 7 |
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.