The common gartersnake, Thamnophis sirtalis, occurs in many parts of Canada and in the non-arid regions of the United States. In Utah, the species occurs primarily in the northern, eastern, and central areas of the state; it is absent from western and southern desert areas. The race, or subspecies, of the common gartersnake that occurs in Utah is the valley gartersnake, Thamnophis sirtalis fitchi.
The common gartersnake eats primarily earthworms, fishes, and amphibians, but insects, spiders, small mammals, and small birds are occasionally consumed. Females of the species give birth to between thirteen and twenty-six live young each year during mid-summer. The common gartersnake occurs in moist habitats, where it is active both during the day and at night. During cold times of the year, individuals of the species move underground or under cover and become inactive.