Common Gartersnake (Thamnophis sirtalis) – Amphibians and Reptiles of Iowa

Common Garter Snake  (Thamnophis sirtalis)

Alternate names : Common Gartersnake
by Jeff LeClere

No condition. Garter snakes are afforded no protection in Iowa. Common garter snakes are found statewide.

Harmless to humans. The common garter snake is a average sized Iowa snake measuring 14 – 48 inches in duration ( Conant and Collins, 1991 ). The grind color is inner light brown to black with two alternating rows of black spots. Some specimens have a lighter brown background color in which the spots stand out particularly well. There are three longitudinal stripes. The abaxial stripe is normally jaundiced. The lateral stripes are cream to yellow and are located on the second and third gear scale rows. There is normally a row of black spots below the lateral pass stripes .

The belly may be white, yellow, or bluish. A specimen from Ringgold County had red pigment on the bottom of the buttocks. The headway is brown university or black with one or two little jaundiced dots near the parietal scales atop the point ( these may be lacking ) and none or identical few dark black bars on the labial scales. The scales are keeled and the anal plate is single. The similarly check plains garter snake and westerly ribbon snake have the lateral pass stripes on rows three and four .
There are two subspecies of the common garter snake that are found in Iowa. The easterly garter snake, Thamnophis sirtalis sirtalis, normally has white, mint green, orange or red on the peel BETWEEN the scales ( normally entirely visible when the peel is stretched such as after a boastfully meal ). The red-sided garter snake, Thamnophis sirtalis parietalis, is very alike, differing entirely by the presence of boldface red bars or spots on the sides between the dorsal and lateral pass stripes. This red coloration is normally visible without any stretch of the skin. Both of these subspecies may besides be called park garter snakes. Either subspecies may be found anywhere in the state .


According to Conant and Collins ( 1991 ), the eastern garter snake is basically found in eastern Iowa, while the red-sided garter snake inhabits the western helping of the state. however, these subspecies intergrade heavily in Iowa. Individuals besides vary in color, frankincense specimens resembling either subspecies may be found anywhere in the express. The park garter snake is found statewide .

The common garter snake is one of Iowa ’ s most park and familiar snakes. They occur about anywhere there is adequate food and shelter. They are extremely adaptable to environmental changes, much like the plains garter hydra. Unlike the plains garter hydra, however, most coarse garter snakes prefer damp habitats, and may be found at the urine ’ south edge. open plains, grasslands, and forests or forest edge are besides inhabited equally well. City ballpark, vacant lots, farmlands, or suburban backyards are besides utilize .

This is a diurnal, active hydra that may be more aggressive than the plains garter snake. In summation to biting, it frequently expels a foul smell musk and body waste to dissuade enemies. If cornered, it may strike ( but its bite is painless ), or it may hide its lead under its coils, raise its tail in the air, and lento wag its stern back and forth. They are active thermoregulators and will alternately hunt and bask throughout the day. They take refuge underneath logs, rocks, boards, and in mammal burrows. They breed in the bounce and the young are born alive in late summer or fall. There may be 10 – 70 or more in a litter and are 5-8 inches in length. A female found road-killed in Stevens County, Minnesota on June 13 contained 36 growing follicles.

They may overwinter with other species of snakes and use any place they can to get below the frost line. road embankments, mammal burrows, and basements are coarse overwintering sites. Great numbers of these snakes may be seen crossing roads in October as they migrate to their winter spots. I have seen many juveniles during this time in Polk and Cherokee counties. During the final few years, coarse garter snakes have been seen on ardent days during every calendar month of the year .

coarse garter snakes are rapacious feeders and will eat anything they can catch and swallow. Earthworms, fish, frogs, toads, salamanders, mouse, and birds ’ eggs are consumed. These snakes eat carrion and will eat dead animals of many kinds that are little enough to swallow. I found and removed a specimen in Scott County, Minnesota from the road two or three times as it attempted to eat a very honest-to-god DOR frog that was stuck to the paving. normally the affectionate they are, the more kinds of food they will accept. They eat their prey without constriction, frankincense they have firm jaws to overpower their prey .