Eastern Garter Snake (Thamnophis sirtalis)

Description: The eastern garter snake (Thamnophis sirtalis) is usually 18 – 26 in (45.7 – 66 cm) long, but occasionally reaches lengths up to 49 in (124 cm). Most individuals can be distinguished from other species by the presence of three yellow longitudinal stripes down a dark body. Some, however, exhibit a checkered body pattern with light stripes and a grayish or reddish body color. Specimens from southern Georgia and Florida are often bluish in background coloration. The belly of garter snakes is white or light yellow. Garter snakes are similar in appearance to ribbon snakes (Thamnophis sauritus) but ribbon snakes are generally more slender and garter snakes have vertical black lines on their lip scales. Additionally, in garter snakes the lateral yellow lines are on scales 2 and 3 whereas they are on scale rows 3 and 4 in ribbon snakes. On garter snakes they are on scales 2 and 3. Males generally have longer and thicker tails than females.

Range and Habitat: Garter snakes are common throughout the Southeast and most of North America and are found in a wide variety of habitats, including meadows, marshes, woodlands, and hillsides. They tend to prefer moist, grassy environments and are often found near water, such as the edges of ponds, lakes, ditches, and streams. However, they are not always found near permanent water sources and may sometimes travel long distances from any water, They are common among the most commonly-encountered snakes in suburban areas, provided there is some cover (debris, boards, vegetation, logs, or rocks).

Habits: Garter snakes may be active by day or night and are often found under boards or other debris. They are viviparous (give birth to live young) and sometimes have more than 50 babies. Common garter snakes feed on worms, slugs, frogs, toads, salamanders, fish and tadpoles. They may be active throughout the year, including warm winter days.

Conservation Status: Garter snakes are common in our region and are not protected throughout most of it. This species is protected throughout the state of Georgia.

Pertinent References:

Gibbons, W., and Dorcas, M. 2015. Snakes of the southeast. University of Georgia Press.

King, Richard B. Mendelian inheritance of melanism in the garter snake Thamnophis sirtalis. Herpetologica 59 (4). 2003.

Account Author: Amelia Gleaton, University of Georgia – edited by J.D. Willson