Plains Gartersnake

Thamnophis radix


Photo of a plains gartersnake taken in Lakewood, Colorado.
The plains gartersnake is an attractive, medium-sized gartersnake with a yellowish-orange stripe down the middle of the back.
Joseph Berger,
Other Common Name
Plains Garter Snake

Colubridae (nonvenomous snakes) in the order Squamata (lizards and snakes)


An attractive, medium-sized snake of wet meadows and marshes. Very similar to the other gartersnakes, but it usually has a yellowish-orange stripe down the middle of the back. The general color is greenish gray, olive, or brown. A light stripe on each side may be yellow, green, or blue. The area between the light stripes usually has an alternating double row of black spots. The light green upper lip has black bars along the edges of the scales. The belly is gray or greenish gray with a row of black spots along each side. Like other gartersnakes, when captured or molested, this snake will smear a musky secretion from glands at the base of the tail.


Length: 15 to 28 inches.

Plains Gartersnake near Jamesport at Woods Crossing

Plains Gartersnake near Jamesport at Woods Crossing
Plains Gartersnake near Jamesport at Woods Crossing
Plains Gartersnake near Jamesport at Woods Crossing
Habitat and conservation

This gartersnake lives on or near meadows, wet prairies, marshes, lakes, and ponds. It takes shelter under logs, boards, rocks, or other objects. Winters are spent underground, probably in abandoned rodent tunnels.


Like other species of gartersnakes, this snakes feeds mainly on earthworms, minnows, salamanders, tadpoles, toads, frogs, and occasionally small rodents.

Plains Gartersnake Distribution Map
Distribution in Missouri

Occurs mainly in the northwestern corner and in north-central Missouri, with an isolated population in the eastern part of the state near St. Louis.


The plains gartersnake used to be separated into two subspecies, the eastern plains gartersnake (T. r. radix) and western plains gartersnake (T. r. haydeni). Most scientists have now agreed that the differences between these are not great or distinct enough to warrant official subspecies status, so they are all lumped together as "plains gartersnake" (T. radix).

Life cycle

This attractive species spends warm summer days basking in the sun or searching for food. It is normally active from late March to late October. Courtship and mating occur in the spring and possibly also in autumn. Young are born from late July through early September, with 5-60 or more young per litter, and 9 being an average. Newly born plains gartersnakes are about 6-7½ inches long.

Human connections

Fear and myth still surround snakes, due largely to a lack of knowledge about them. Fortunately, the biology and natural history of Missouri snakes are both interesting and enjoyable to learn. People who understand snakes tolerate and appreciate them as a natural part of outdoor Missouri.

Ecosystem connections

As predators, gartersnakes help keep populations of other animals in check. Although they can defend themselves by trying to bite and by smearing foul-smelling musk on attackers, they and their young provide food for many predators.