Butler's garter snake (Thamnophis butleri)

Mildly venomous but not dangerous: the Butler's 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.

The Butler's garter snake's U.S. record is concentrated: Michigan alone holds 77% of licensed records. It is listed in 3 states in all; the next are Ohio (57) and Wisconsin (22).

Across the U.S., observation records of the Butler's garter snake run mostly April through September, peaking in April with 35% of them. Almost none are from December to February.

Michigan holds 284 licensed records, the 6th most recorded of 17 snakes listed there. Most of its licensed records in Michigan come from Washtenaw County, Wayne County and Jackson County. Next come Monroe County (22) and Livingston County (10).

Ohio holds 57 licensed records, the 18th most recorded of 25 snakes listed there. Most of its licensed records in Ohio come from Erie County, Lucas County and Licking County. Next come Fairfield County (4) and Franklin County (4).

The Butler's garter snake record leans on older material: only 12% of dated U.S. records come from 2017–2026, and the median record is from 1971. The oldest dated record is from 1853; the busiest year was 1994, with 37 records.

Of the 28 counties where the Butler's garter snake is most recorded, 15 are also top counties for the eastern massasauga, more than for any other snake. Venomous species among its neighbors: the eastern massasauga.

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.