The species name "constrictor" would lead one to think this is a constricting snake. This is not true. When the Swedish naturalist Linnaeus first described and named this species in 1758, he may have had it confused with the Black Rat Snake (Pantherophis obsoletus), which is a true constrictor (Morris, 1944).
This is one of the largest snake species in Michigan (Harding 1997).
As with many snakes, vision and olfaction are important percptual channels for racers.
Perception Channels: visual ; tactile ; chemical
This species is still abundant in some places. A few states (Maine and Louisiana) and the Canadian province of Ontario give it legal protection because it is rare there.
Pesticide residue poses a danger to insectivorous young racers. The dangers faced by adults include their habitat reduction because of agriculture and suburban/urban development along with direct killing of snakes by people (Harding, 1997).
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Racers have no known neagtive impact on humans. If handled or harassed, they may bite, but will not deliberately confront a human.
Negative Impacts: injures humans (bites or stings)
Racers are beneficial to humans in that they destroy rodent and insect pests (Harding, 1997).
Positive Impacts: controls pest population
Coluber constrictor is a mid-level predator, eating many kinds of smaller animals, but in turn eaten by larger predators.
Racers are carnivores. They have very broad diets. Juvenile racers eat mainly insects, spiders, small frogs, small reptiles (including lizards and snakes and their eggs) and young rodents and shrews. As racers grow, they take larger prey as well, including nestling birds and their eggs, other mammals as large as squirrels and small cottontail rabbits, small turtles and larger snakes (Greene, 1997). Their food is not constricted as the name would imply, instead a loop of the snake's body is thrown over the struggling victim, pressing it down so that it can be swallowed (Conant and Collins, 1998).
Animal Foods: birds; mammals; amphibians; reptiles; eggs; insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Eats terrestrial vertebrates, Insectivore )
Racers occur from southern Canada to Guatemala, with considerable individual and local variation in regions where two or more subspecies intergrade (Conant and Collins, 1998). Different racer subpopulations include: The northern black racer, Coluber constrictor constrictor, ranges from southern Maine and central New York south to northern Georgia and Alabama. The blue racer, C. c. foxii, is found from Michigan, Wisconson, and Minnesota south to Ohio, Indiana, and Illinois. C. c. priapus, the southern black racer, ranges from southern Indiana and Illinois and southeastern North Carolina to central Florida and southern Arkansas. It also occurs on some of the Florida Keys. The Everglades Racer, C. c. paludicola, is found only in southern Florida. The brownchin racer, C. c. helvigularis, occurs only in the lower Chipola and Appalachicola River valleys in Georgia and Florida. C. c. latrunculus, the blackmask racer, occurs in southeastern Louisiana and adjacent Mississippi. The eastern yellow-bellied racer, C. c. flaviventris, is found from extreme southern Saskatchewan southeast through Montana, western North Dakota, east to Iowa and south to Texas. The western yellow-bellied racer is found west of the Rocky Mountains, from southern California and Nevada through through western Colorado, Oregon, and Washington and into southern British Columbia. The buttermilk racer, C. c. anthicus, ranges from south Arkansas to Louisiana, also eastern Texas. C. c. etheridgei, the tan racer inhabits Louisiana and Texas. C. c. oaxaca, the Mexican racer, has isolated populations in New Mexico, but its main range is from south Texas to Veracruz.
Biogeographic Regions: nearctic (Native )
Racers prefer dry sunny areas with access to cover, including old fields, open woodland, hedgerows, thickets and wood edges, sometimes damper sites such as bogs, marshes, and lake edges are also used. In the Great Lakes region, racers occupy a home area that may range in size from 2.5 acres (1 ha) to 25 acres (20 ha) depending on the productivity of the habitat (Harding, 1997). During several cold months of the year racers are inactive in shelters hidden from subfreezing temperatures. Fall and spring activity peaks are associated with movement to and from the hibernacula as well as mating and feeding (Greene, 1997).
Habitat Regions: temperate
Terrestrial Biomes: savanna or grassland ; chaparral ; forest ; scrub forest ; mountains
Wetlands: marsh ; swamp ; bog
Other Habitat Features: agricultural
In the wild, racers have been known to live over 10 years.
Range lifespan
Status: wild: 10 (high) years.
Average lifespan
Status: captivity: 10 years.
The mature racer has very smooth shiny scales with a divided anal plate (Conant and Collins, 1998). There are 17 scale rows midbody, and 15 near the tail. The normal coloration is a very dark and uniform dorsum with variations ranging from black, bluish, gray, to olive brown. The head is narrow but still wider than the neck with very distinct brow ridges. The chin and throat areas vary from white to yellowish progressing back to a ventrum that could be black, dark gray, light blue, white, cream or yellow. The average adult length ranges from 90-190 cm. (35-75 in.) (Harding, 1997).
Juvenile racers are strongly patterned with grays, browns, and reds. The coloring fades as the snake grows older and at 30 inches all traces have usually disappeared (Conant and Collins, 1998).
Male racers can be distinguished from the female of the species in that the tail is longer with a wide base, sometimes even a bulge. The female's tail tapers abruptly from the body (Harding, 1997).
Range length: 191 (high) cm.
Other Physical Features: heterothermic
Sexual Dimorphism: sexes shaped differently
Racers are eaten by birds, dogs, cats, and coyotes.
Known Predators:
Mating takes place in the spring, from late April until early June. In June or early July the female will lay 3-32 oval, white eggs in a hidden nest site. Suitable nest sites may be a rotted stump or log, and old mammal burrow, or a nest cavity in the leaf litter or sand (Harding, 1997). The eggs are 2.5 to 3.9 cm long and are coated with small nodules resembling hard, dry grains of salt. Hatching usually occurs in August or early September with young size approximately 7.5-14 inches (39 cm) long (Conant and Collins, 1998). Males become sexually mature in 1 to 2 years, while females mature slower, approximately 2 to 3 years. Racers have been known to oviposit communally, one case reported shows that almost 300 eggs were found in a talus slide. They originated from at least 50 racers, sharp-tailed snakes (Contia tenuis), ring-necked snakes (Diadophis punctatus), and gopher snakes (Pituophis catenifer) (Greene,1997).
Breeding interval: Mating takes place in the spring, from late April until early June.
Breeding season: June to early July
Range number of offspring: 3 to 32.
Range age at sexual or reproductive maturity (female): 2 to 3 years.
Range age at sexual or reproductive maturity (male): 1 to 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; oviparous
