Plains Gartersnake

Photo of a plains gartersnake taken in Lakewood, Colorado.
Scientific Name
Thamnophis radix
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.

Other Common Names
Plains Garter Snake
Length: 15 to 28 inches.
Where To Find
Plains Gartersnake Distribution Map
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.
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.
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.
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.
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.
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Similar Species
About Reptiles and Amphibians in Missouri
Missouri’s herptiles comprise 43 amphibians and 75 reptiles. Amphibians, including salamanders, toads, and frogs, are vertebrate animals that spend at least part of their life cycle in water. They usually have moist skin, lack scales or claws, and are ectothermal (cold-blooded), so they do not produce their own body heat the way birds and mammals do. Reptiles, including turtles, lizards, and snakes, are also vertebrates, and most are ectothermal, but unlike amphibians, reptiles have dry skin with scales, the ones with legs have claws, and they do not have to live part of their lives in water.