Illinois Natural History Survey - University of Illinois

Storeria dekayi (Holbrook, 1836) -- Dekay's Brownsnake

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S.dek_107.jpg Sdek_head.JPG SdekMassac.JPG
photo by C.A. Phillips photo by C.A. Phillips Massac Co., IL photo by C.A. Phillips


Key Characters: Prominent dark blotch on either side of neck; a dark spot under each eye; one preocular scale; back scales strongly keeled and in 17 rows; anal plate divided.

Similar Species: Red-bellied Snake, Ring-necked Snake. See the Key to Illinois Snakes for help with identification.

Subspecies: Four subspecies are currently recognized. Only the Midland Brownsnake, Sdwrightorum Trapido, 1944, is thought to inhabit Illinois.

Description: Small (up to 45 cm TL) gray or light brown snake with two rows of small, dark spots on the back. On some individuals back spots are connected by side bars to form a ladderlike pattern. Usually a faint light stripe on midback. Belly light pink. Juveniles have a gray or white collar behind the head.

Habitat: Variety of forest and prairie habitats, floodplains and uplands, forest edges, even cultivated fields, and especially in vacant lots in cities.

Natural History: Abundant where there is much surface cover and an abundant supply of food. Mates in April and May and gives birth to 5-25 young from late July through early September. Newborn 5-12 cm TL. Eats mainly earthworms and slugs, and is preyed upon by snakes, birds, mammals, and even large toads and spiders. Large numbers are killed on roads separating cultivated fields from forested rocky bluffs each spring and autumn as they move to and from hibernacula.

Status: Common throughout most of the state.

Etymology: Storeria - (New Latin) in honor of David H. Storer (1804-1891); dekayi - (New Latin) in honor of James E. DeKay (1792-1851); wrightorum - in honor of Albert H. and Anna A. Wright.

Original Description: Holbrook, J.E. 1836 ? 1839. North American Herpetology. J. Dobson and Son, Philadelphia. For wrightorum; Trapido, H. 1944. The snakes of the genus Storeria. American Midland Naturalist 312(1):1-84.

Type Specimen: Syntype. ANSP 5832.  For wrightorum; Holotype. UMMZ 78583

Type Locality: "Massasachusetts, New York, Michigan, Louisiana". For wrightorum; "Reelfoot Lake, Tennessee"

Original Name: Coluber Dekayi Holbrook, 1836 (probably 1839).

Nomenclatural History: Relatively stable in the Illinois literature.

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