Eastern Ribbonsnake

Thamnophis sauritus (Linnaeus, 1766)

Key Characteristics: Side stripes on scale rows 3-4; midback stripe yellow; if present, pair of spots on top of head faint and never touching each other; back scales keeled; anal plate not divided.

Similar Species: Western Ribbonsnake, Common Gartersnake, Plains Gartersnake. See the Key to Illinois Snakes for help with identification.

Subspecies: Four subspecies are currently recognized, but only the Common Ribbonsnake, T. ssauritus is known to inhabit Illinois.

Description: Medium-sized (up to 80 cm TL), slender black snake with a yellow midback stripe and a yellow stripe on each side. A brown stripe on scale rows 1-2 extends onto the sides of belly scales. Remainder of belly plain greenish white. Two rows of black spots between back and side stripes. Long tail about one-third body length.

Habitat: Lowland forests, in vegetation along banks of sloughs, cypress-tupelo swamps, and other similar bodies of water.

Natural History: A quick, wary snake that moves to water, shoreline vegetation, or holes in the soil when disturbed. Mates in April or May and gives birth to 10-15 young between July and October. Amphibians make up most of the diet, but fish and invertebrates also eaten. Predators include wading birds, mammals, and other snakes.

eastern ribbonsnake distribution in IllinoisStatus: Endangered in Illinois. Threats include drainage of swamplands and loss of aquatic and riparian vegetation. Known only from southeastern counties.

Etymology: Thamnophis – thamnos (Greek) meaning shrub, bush; ophio (Greek) meaning serpent, reptile; sauritus – sauros (Greek) meaning lizard, reptile

Original Description: Linnaeus, C. 1766. Systema Naturae per Regina tri Naturae secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis. 12th ed. Salvii, Stockholm. 1:532 pp.

Type Specimen: Neotype. FMNH 73119.

Type Locality: South Carolina, Charleston County, Charleston.

Original Name: Coluber saurita Linnaeus, 1766

Nomenclatural History: This species has a very complicated nomenclatural history. It was transferred to the genus Eutainia by Baird & Girard (1853), but Kennicott emended the name to Eutania and named Esackenii, which was later placed in synonymy of sauritus. Davis & Rice (1883) used Eutaenia for the Eastern Ribbonsnake as Eutaenia saurita.