Plains Garter Snake Thamnophis radix by Jeff LeClere Status No status assigned in Minnesota. The plains garter snake is a medium sized Minnesota snake measuring 14 to 43 inches in length. It is non-venomous and can be more docile than the common garter snake. The ground color is light brown to black with two alternating rows of black spots.
Some specimens have an olive green background color in which the spots stand out especially well.
There are three longitudinal stripes. The lateral stripes are cream to yellow and are located on the third and fourth scale rows. There is usually a row of black spots below the lateral stripes at the edge of the ventral scales. The belly may be white, yellowish, or bluish. The scales are keeled and the anal plate is single.