General Description: The Red-bellied Snake is a small terrestrial snake, with adults ranging from 10–12 inches (25.4–30.5 cm) in length. The background coloration is variable and can be tan, brown, or gray, typically with a pale middorsal stripe. This stripe may be difficult to discern as it can match the background coloration. Often, this middorsal stripe is bordered by a series of small black dots that may be connected, giving the appearance of thin stripes running down the length of the body. The head is dark in coloration and three pale blotches (two lateral, one middorsal) are present on the neck. The belly is red in coloration and can be light red or deep red. Juvenile coloration is similar to adult coloration. Scales are keeled and the anal scale is divided. Red-bellied Snakes are similar in appearance to Dekay’s Brownsnakes (Storeria dekayi), but can easily be differentiated by the presence of a red belly (Dekay’s Brownsnakes have a white belly).
Behavior: Red-bellied Snakes are active from April to September and may even be active into October provided warmer temperatures. Similar to most other snakes, this species is solitary in behavior. Individuals can be found in close proximity while they are overwintering in den sites and when males seek out females during the reproductive season. Hibernacula are typically rocky outcrops or small mammal burrows. Earthworms are the primary prey of Red-bellied Snakes, though other invertebrates may also be consumed.
Reproduction: Mating is thought to occur in the early spring after emergence from overwintering sites. Red-bellied Snakes are viviparous, giving birth to 2–21 live young in the late summer. Sexual maturity is reached in 2–3 years.
Habitat: Red-bellied Snakes use many different habitats including riparian woodlands, wet meadows, and residential areas throughout their range.
Species Range: This species has a large distribution across much of the eastern half of the United States, with populations in the Black Hills being the westernmost known locality of this species.
South Dakota Range: Red-bellied Snakes have a disjunct distribution in South Dakota. Populations occur in the Black Hills and along the eastern boundary of South Dakota with Minnesota and Iowa. Black Hills populations have been described as the Black Hills Red-bellied Snake (Storeria o. pahasapae).
South Dakota Status: This species is monitored by the South Dakota Natural Heritage Program. Any sightings of this species should be reported to South Dakota Game, Fish and Parks (report observation).
Account written by Drew R. Davis and Cyrus J. Sorenson