Illinois Natural History Survey - University of Illinois

Squamata     suborder Serpentes
Thamnophis sauritus -- Eastern Ribbonsnake

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Johnson County, IL; photo by Mike Redmer distribution map

Purple shade indicates vouchered specimens. Light blue (cyan) shade indicates photographic records. Yellow shade indicates verified sighting. Slanted hatch indicates pre-1980 records only

NOTE: Not all specimens upon which these maps are based have been verified.

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.

Subspecies: Eastern ribbonsnake, T. s. sauritus; northern ribbonsnake, T. s. septentrionalis.

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.

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


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