Garter snakes are widespread and commonly encountered across North America, often found in gardens, yards, and various natural habitats. Understanding their physical characteristics can help individuals identify these generally harmless snakes, alleviating common misconceptions and fears. While their appearance varies, certain features remain consistent across many species and subspecies.
Overall Body and Size
Garter snakes have a slender to medium build, appearing relatively thin. Adults average 18 to 26 inches (46 to 66 cm) in length, though larger individuals can reach up to 51 to 54 inches (130 to 137 cm). Females are larger than males and have longer tails. Their coloration varies widely, commonly including shades of black, brown, gray, green, or olive. Some can also display hues of blue, yellow, or red.
Signature Striped Markings
Most garter snakes have longitudinal stripes. These stripes are often brightly colored, appearing in shades of yellow, cream, white, blue, or green. They usually have three stripes: a prominent central dorsal stripe and two lateral stripes on each side. These lateral stripes are commonly found on the second and third rows of scales counting upward from the belly.
The intensity and clarity of these stripes can differ among individual snakes and species. A checkerboard pattern or irregular spots may be visible between the longitudinal stripes in many garter snakes. For instance, some subspecies, like the red-sided garter snake, feature vertical red or orange bars interspersed within the darker background color between the stripes. While most garter snakes have these markings, some individuals or subspecies may have reduced striping or be entirely stripeless.
Head and Scale Details
The head of a garter snake is small and slightly distinct from its neck, giving it an elongated or oval appearance, unlike the broad, triangular shape of some venomous snakes. When threatened, however, they can flatten their heads, making them appear wider. Their eyes are large and prominent, with round pupils. This round pupil shape is characteristic of many diurnal, non-venomous snakes.
Garter snakes have keeled scales. This means each scale has a raised ridge running down its center, giving the snake’s skin a rougher, textured feel rather than a smooth one. Keeled scales are a consistent feature across many garter snake species. Garter snakes have a forked tongue, often red with a black tip. They also often have dark vertical lines or markings along the edges of their upper lip scales.