Snakes in South Dakota

South Dakota has about 10+ species of snakes, and only 1 of them is venomous. That means nearly every snake you come across in the state is harmless. South Dakota's mix of prairie, river, and badland country supports a modest but interesting set of snakes, most of them shy grassland and wetland hunters that keep rodent and insect numbers in check.

The state divides neatly along the Missouri River. East of the river is glaciated prairie pothole country, with rolling tallgrass and mixed-grass prairie, farmland, and shallow wetlands. West of the river the land grows drier and more rugged, with shortgrass prairie, the eroded Badlands, and finally the forested Black Hills rising in the far southwest. The dry western breaks and badlands are prime habitat for the state's one venomous snake.

South Dakota's single venomous species is the Prairie Rattlesnake, common in the dry western half, the Badlands, prairie-dog towns, and rocky outcrops, and largely absent east of the Missouri River. It dens in rock crevices, basks on south-facing slopes, and prefers to retreat or stay still rather than confront a person. Encounters are most likely in the open western country, and bites remain uncommon.

Most snakes South Dakotans see are harmless. Common and plains garter snakes are the most encountered, in wet meadows, gardens, and along sloughs. Bullsnakes (gophersnakes) are widespread on the prairies and hiss loudly and rattle their tails to mimic a rattlesnake, getting killed needlessly even though they are excellent rodent hunters. Plains hognose snakes put on a dramatic flattening, hissing bluff but are no threat, and watersnakes patrol rivers and ponds. Bites are uncommon and rarely fatal thanks to antivenom, and most happen when people try to handle or kill a snake. Never assume a wild snake is safe to handle, and if a bite happens, call Poison Control at 1-800-222-1222 or 911.