Blue Racer

Overview:

Scientific Name: Coluber constrictor foxi
Size: 35 – 75” (adult total length)
Status: Generally common, though populations in Southern Michigan have experienced declines while some in Northern Michigan have experienced range expansions.
MDNR Wildlife Action Plan Status: Species of Greatest Conservation Need

Blue Racer

Habitat:

Preferred habitat is dry and sunny with access to cover, including shrubby fence lines, old fields, hedgerows, thickets, open forest, and woodland edges. More moist areas, including grassy lake edges and marshes, are also sometimes occupied.

Adult Coloration:

May be a uniform gray, bluish gray, turquoise, olive, or brown above, with a slightly darker head and usually a black “mask” behind the eye. Belly is generally bluish, white, or cream. Upper labial (lip) scales are whitish or yellowish, as are chin and throat.

Adult Characteristics:

Large active snakes with unkeeled shiny scales. Eyes are large and have distinct brow ridges. Anal plate is divided. Males have slightly longer tails that bulge near the vent due to hemipenes (reproductive structures).

Juvenile Characteristics:

Newborns can be 7.5 – 14” in length, and are decorated with a pattern of gray, brown, or maroon dorsal blotches with black borders on a gray or brown background. The head, belly, and sides are pigmented with many dark spots. The pattern gradually fades with age and is usually replaced by adult coloration by the time the snake reaches a length of 27.5 – 35” around the age of 2 or 3 years.

Scale Count:

17 scale rows at midbody

Species Confused With:

Black Rat Snakes and Fox Snakes both have weakly keeled scales and a nearly square cross section body shape, while the Blue Racer has smooth scales and a nearly round body. Young Black Rat Snakes have a black stripe from the eye to the back edge of the jaw. Black (melanistic) Eastern Garter Snakes have heavily keeled scales and an undivided (single anal plate).

References:

Amphibians and Reptiles of the Great Lakes Region by Jim Harding
Harding, J.H. and J.A. Holman. 2006. Michigan Snakes. MSU Extension Ext. Bulletin E-2000,74 pp. [revised].
Ruthven, A. G., H. B. T. Gaige, et al. 1912. The herpetology of Michigan, by Alexander B. Ruthven. Crystal Thompson and Helen Thompson; Memoranda towards a bibliography of the archaeology of Michigan, by Harlan I. Smith; prepared under the direction of Alexander G. Ruthven. Lansing, Mich., Wynkoop Hallenbeck Crawford, State Printers.
Holman, J. A. 2012. The Amphibians and Reptiles of Michigan: A Quaternary and Recent Faunal Adventure. Detroit, Mich., Wayne State University Press.
Conant, R., and Collins, J. T. 1998. Reptiles and Amphibians: Eastern, Central North America. Houghton Mifflin Harcourt Press.