The checkered garter snake is a species of snake with distinctive black spots. These snakes are found in areas of California, Arizona, New Mexico, Texas, and Kansas in the United States, and also in Mexico and Central America. The scientific name for the checkered garter snake is Thamnophis marcianus.
Usually between 18 and 42.5 inches (47.7–108 cm) long, checkered garter snakes are shades of brown or green-brown. They have a yellow-white strip on their backs which travels the length of their bodies, pale yellow bellies, and are covered in black, check-like markings. Their scales are keeled, which means these snakes are rougher to the touch and more dully colored than snakes with smooth, glossy scales.
The checkered garter snake does not have any set activity period. In cooler regions, this snake is usually more active during the day. Conversely, in warmer regions it will be more frequently nocturnal. Checkered garters are strong swimmers and may dive in the water to avoid perceived danger. When handled, they often release fecal matter and strong smelling musk as a defense mechanism.
Despite living mostly in arid regions, checkered garter snakes are usually found near a water source. They eat lizards, fish, invertebrates, and small mammals, but their favorite food is amphibians. Although these snakes are considered harmless to humans, they do have a toxin in their saliva that is lethal to their prey. The toxin may cause irritation to humans if bitten. Checkered garters are considered very docile, however, and rarely bite.
Unlike many other snake species, garter snakes bear live young. Between June to August, a female checkered garter will birth 6–18 offspring. The young are about 8–9.25 inches (20.3–23.5 cm) long. Juvenile snakes will often eat earth worms.
There are three subspecies of the checkered garter snake. Thamnophis marcianus bovallii is found primarily in Nicaragua, and Thamnophis marcianus praeocularis is found in some regions of Central America. Thamnophis marcianus marcianus, or Marcy's checkered garter snakes, are the primary subspecies found in the United States and northern Mexico. This species is often sold as a pet and exhibits an albino color form.
Though garter snakes are generally common, and this garter species is a popular pet, in Kansas, the checkered garter snake is considered a threatened species. It is listed as protected by the Kansas Nongame and Endangered Species Act. Areas of land in southern Kansas have been set aside to preserve its habitat.