Coluber constrictor

Upper surface of adults varies from black (e.g., northeastern U.S) to plain brown or olive (most of western and central U.S.), with a spattering of white, yellowish, buff, or pale blue in some parts of the south-central United States; upper scales smooth (unkeeled); belly black (e.g., northeastern U.S.) to plain yellow or cream (western and central U.S.); eyes large; anal scale divided; nostril bordered by two separate scales; usually 15 dorsal scale rows just anterior to the vent; lower preocular scale (lowermost scale in front of the eye) wedged between upper lip scales. Total length up to around 190 cm in the northeastern U.S., much smaller (usually less than 90 cm) in the west. Hatchling: upper surface with numerous brown blotches on a paler background; eyes relatively huge. Source: Hammerson (1999).

Habitats encompass a wide range of lowland and montane areas, including deserts, prairies, sandhills, shrublands, woodlands, forests, canyons, streamsides, and semi-agricultural areas. This snake is absent from the driest deserts and highest mountains (subalpine zones and higher). It commonly climbs shrubs and small trees. When inactive, it hides underground, in crevices, or under surface cover. Adults often hibernate communally, sometimes partly submerged in water. Eggs are laid in underground tunnels or burrows, rotting stumps, sawdust piles, or under rocks. Oviposition sites may be up to at least several hundred meters from the usual home range (Brown and Parker 1976, Iverson et al. 1995).

Home range size was estimated at 1.4 ha for nongravid females in Utah (Brown and Parker 1976), about 10 ha in Kansas (Collins 1982). In South Carolina, summer home range was 5-21 ha (mean 12 ha); movement on active days was 74-135 m (mean 104 m); home ranges overlapped (Plummer and Congdon 1994). Population density was estimated to be 0.65/ha in Utah (Brown 1973), up to about 15/ha in Kansas. Estimated adult annual survivorship was 79% in Utah, 62% in Kansas, 54% in Michigan (Rosen 1991).

When confronted by a person, racers, like many harmless snakes, sometimes vibrate the tail. In dry vegetation, this may produce a sound similar to that make by a rattlesnakes rattle.

Eggs laying occurs in June or early to mid-July in most areas. Eggs laying peaks early to mid-June in southern Michigan (Rosen 1991), late June or early July in Utah/Colorado. Clutch size is usually 5-28, averages higher in the east than in the west; mean clutch size about 6 in Utah, 12 in Kansas, 15 in Michigan (Rosen 1991). Eggs hatch in about 6-9 weeks, generally in August or early September. Females become sexually mature in 3 years in Utah, 2-3 years in Kansas, 2 years in Michigan (Rosen 1991). Sometimes this snake nests communally.