When encountering a black snake with yellow stripes, people often wonder about its identity. Several North American snake species exhibit this distinctive coloration, leading to confusion. Identifying them requires understanding their specific features and their role in local ecosystems.
Common Black and Yellow Striped Snakes
The most frequently encountered snakes fitting the description of black with yellow stripes belong to the genus Thamnophis, commonly known as garter snakes and ribbon snakes. Garter snakes (Thamnophis spp.) are widespread across North and Central America. Their body color ranges from black, brown, or gray to olive, typically adorned with three longitudinal stripes that are usually yellow, white, or green, though some may also display red or blue hues. These snakes generally measure between 18 to 51 inches in length, with many common varieties falling within the 18 to 26-inch range.
Ribbon snakes (Thamnophis saurita) are closely related to garter snakes. They are notably more slender than garter snakes and possess a proportionately longer tail. Their dark bodies, which can be black, brown, or dark green, are typically marked with three prominent stripes of yellow, white, or blue. Ribbon snakes usually grow to a total length of 16 to 35 inches.
Key Identification Features
Distinguishing garter and ribbon snakes involves observing specific physical characteristics. Ribbon snakes have a more slender body profile and a tail that makes up one-third or more of their total length, contrasting with the thicker build and shorter tail of garter snakes. This difference in body proportion is often the most immediate visual cue.
Another distinguishing feature is the placement of their lateral stripes. Garter snake lateral stripes typically run along scale rows 2 and 3 on their sides, while ribbon snakes usually have their lateral stripes positioned higher, on scale rows 3 and 4. Ribbon snakes often display a distinct white or pale marking directly in front of each eye, a feature generally absent in garter snakes. Their heads may also appear distinctly bicolored, with a dark top and white under the eyes and chin. Both garter and ribbon snakes possess keeled scales (scales with a raised ridge).
Habitat and Behavior
The habitats and behaviors of garter and ribbon snakes, while sharing similarities, also present notable differences. Garter snakes are adaptable, found in diverse environments like forests, fields, and suburban areas. While they often prefer areas near water, they are not exclusively restricted to aquatic environments. They utilize various forms of cover, such as rocks, logs, and dense vegetation, for shelter.
In contrast, ribbon snakes exhibit a stronger preference for wetlands and are seldom found far from shallow aquatic habitats, such as the shorelines of ponds, streams, and marshes. Both snake types are carnivorous.
Garter snakes are opportunistic feeders with a diverse diet that includes slugs, earthworms, leeches, various amphibians (frogs, newts, tadpoles), small fish, insects, and rodents. Ribbon snakes, due to their more aquatic lifestyle, primarily consume amphibians like frogs, toads, salamanders, and tadpoles, along with small fish.
Both species are diurnal (active during the day). When threatened, these snakes typically attempt to escape. If cornered, they may coil and strike, hide their head while flailing their tail, or flatten their bodies to appear larger. A common defense mechanism involves releasing a foul-smelling, musky secretion from glands near their cloaca, sometimes accompanied by defecation.
Safety and Coexistence
Common garter and ribbon snakes are generally harmless. While garter snakes produce a mild neurotoxic venom, they lack effective delivery mechanisms to cause significant harm to humans. Any bite from a garter snake is comparable to a bee sting, resulting in only minor localized swelling or bruising. Ribbon snakes are not venomous. Both species are shy and prefer to avoid human interaction.
If one of these snakes is encountered, observe it from a safe distance and allow it to move away naturally. They typically retreat if given the opportunity. To discourage their presence in unwanted areas, remove potential hiding spots like clutter and control pest populations that serve as food sources. These snakes provide valuable ecological benefits, acting as natural pest control by preying on slugs, snails, insects, and rodents.