How to Identify Garter Snakes
Garter snakes (genus Thamnophis), a very adaptable group of snakes, inhabit backyards and multiple grass habitats throughout North America.
Their propensity to inhabit residential areas explains the common name, garden snake, the snakes recognized for their thin and often colorfully striped bodies.
Types of Snakes
Body color ranges from blue, prominent in Florida blue garter snakes, to the many shades of red visible in West Coast species.
Halfway across the country, Texas hosts the Checkered Garter.
Apart from the species with unusual field markings, multiple, similar looking species, occupy overlapping territory in many areas, creating potential identification challenges.
Garter snake identification starts by taking a good picture and applying some basic counting skills.
With respect to picture taking, while the suggestion may sound a bit frightening, keep in mind that garter snakes are typically unaggressive species with less than great eyesight.
Because ground vibrations are often their first indication of a human presence, treading lightly and moving slowly, makes it pretty easy to get within inches of one for a picture.
Extending the digital camera zoom can also capture a good picture for the more timid snake photographer.
With picture in hand, identification starts by noting body color and pattern, belly color, and facial markings. Many garter snake species, for example, have stripes running along the length of their body.
The first and second pictures show the Red-sided Garter Snake (Thamnophis sirtalis), the first from a distance, the second close-up. The close-up picture shows the snake's reddish colored face and lighter colored lower jaw.
The number and shape of the face scales also serves as a useful garter snake identification tool. The second picture, for example, highlights Thamnophis sirtalis's seven upper labials (top lip scales).
The third picture shows the Northwestern Garter snake (Thamnophis ordinoides) taken at close range using a flash. Sometimes they are called a Mountain Garter Snake. The seven upper labials differentiate from the similar looking Thamnophis elegans species, also called a Mountain Garter, which generally have eight upper labials.
Three different subspecies of the Western Terrestrial Garter Snake (Thamnophis elegans) inhabit western North America.
Picture four shows what might be called a typical wandering garter, characterized by the light color stripes. A close up picture would show the snake's eight upper labial scales, typical of all Thamnophis elegans subspecies.
The Valley Garter snake (Thamnophis sirtalis fitchi), one of a handful of T. sirtalis subspecies, shows a light cream or white color on the lower jaw, followed sometimes with a red spot on the neck.
Without seeing the lower portion of the jaw, the Valley garter might be mistaken for other dark headed garter snakes.
Ribbon snakes refers to a group of snakes in the genus Thamnophis, differentiated by the presence of longer tails and a light patch in front of the eye.
Two ribbon snakes, the Western Ribbon Snake (Thamnophis proximus) and the Ribbon Snake, Thamnophis sauritus inhabit North America, each with geographically identified subspecies.
Picture six shows a Gulf Coast Ribbon Snake (Thamnophis proximus orarius), one of the six different subspecies of the Western Ribbon Snake.
© 2007-2012. Patricia A. Michaels