Photo by Brian Johnson

Western fox snake (Mintonius ramspotti) is a medium to large, nonvenomous, rat snake. It is one of the four largest snakes in Minnesota. Adults are usually 36″ to 56″ in length. In Minnesota it occurs mostly in the Mississippi, St. Croix, and Minnesota River valleys. It can be found from April to October in prairies, agricultural fields, woodland openings and edges, lowland meadows, river bottoms, and rocky outcroppings near water.

In the spring and fall adults move about during the day. In the hot summer they move about at night. When confronted they will often vibrate their tails producing a buzzing sound. In leaf litter or dry grass the sound resembles that of a rattlesnake. The reddish head resembles a copperhead. For these reasons the snake is often mistaken for a poisonous one and killed by humans.

http://www.minnesotaseasons.com/Reptiles/western_fox_snake.html