The Plains garter snake (Thamnophis radix) is a slender, medium-sized snake native to the United States and Canada. This species is mildly venomous, although its venom is not toxic to humans.
The Plains garter snake has a distinctive orange or yellow stripe from its head to tail, and the rest of its body is mainly a gray-green color. There are also distinctive black bars on its lip. Its belly is gray-green with small dark spots along the edges. Most have distinctive light yellow spots on the top of the head.
Plains garter snakes are found across a broad area of North America from as far north as central Alberta to as far south as Northern Texas and New Mexico. In the United States, they are also found in Iowa, eastern Wyoming, northern Kentucky, eastern Colorado, Minnesota, southern Wisconsin, Illinois, northwestern Indiana, Oklahoma, Nebraska and the northern half of Missouri. A small population is also in Ohio. In Canada, the species is also found in Manitoba. These snakes live in meadows and prairies near water sources, such as marshes, streams, and ponds. They can also be found in the pinyon-juniper zone, farmlands, abandoned buildings, trash heaps, and vacant lots.
Plains garter snakes are described as "one of the most cold-tolerant snakes"; on warmer winter days, they often come out of hibernation to bask in the sun. They are most active between April and late October depending on location. They prefer to lead a solitary life but will hibernate in small groups. Plains garter snakes are diurnal creatures, however, during the summer may become more nocturnal in order to avoid the heat of the day.
Plains garter snakes are carnivores. They feed on earthworms, fish, slugs, and small amphibians, including the larvae of salamanders. They also eat small mammals and birds, such as Bank swallows and Eastern meadowlarks.
Plains garter snakes are polygynandrous (promiscuous) and both males and females have multiple mates. They usually breed in April or May and birth takes place between August and October. Courtship usually occurs near the communal hibernation site. After a gestation period of 83-102 days, females give birth to 5-60 live young. Snakelets are independent at birth and become reproductively mature when they are 2-3 years old.
There are no major threats to Plains garter snakes at present.
According to IUCN, the Plains garter snake is locally common and widespread throughout its range with adult population size is unknown but undoubtedly exceeds 100,000, probably much more. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
These snakes are important predators of amphibians, earthworms, fish and other animals in their ecosystem.
