Coluber constrictorEastern Racer

Geographic Range

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. (Conant and Collins, 1998)

Habitat

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). (Greene, 1997; Harding, 1997)

Physical Description

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). (Conant and Collins, 1998; Harding, 1997)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    191 (high) cm
    75.20 (high) in

Reproduction

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). (Conant and Collins, 1998; 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

Lifespan/Longevity

In the wild, racers have been known to live over 10 years. (Ernst and Barbour, 1998)

  • Range lifespan
    Status: wild
    10 (high) years
  • Average lifespan
    Status: captivity
    10 years
    AnAge

Behavior

Despite its common name, the racer's actual speed is about 6.5 kilometers per hour (4 mph), or about the rate of a human's brisk walk. If approached by a predator the racer's first option is usually to flee to a nearby burrow, thick vegetation, or rock crevice (Harding, 1997). Often the racer will retreat up into the bushes or low branches of a tree to escape (Conant and Collins, 1998). The racer has some interesting antipredator tactics. A startled adult will begin violent undulatory movement that is quickly changed to a rapid, graceful locomotion for 30 meters or so (Greene, 1997). If cornered, a typical racer will coil and strike while vibrating its tail nervously. The racer is non-venomous, but the slashing bite and recurved teeth may cause bleeding (Harding, 1997). If a predator comes within very close range of the racer it will coil with its head hidden and writhe, smearing scent gland secretions all over its body while alternately assuming an S-coil. If seized the racer will bite and discharge its cloacal contents while twisting its entire body so strongly that sometimes the tail is broken off. The juveniles' distinct color patterns probably mean they rely on camoflage for escape from predators rather than the tactics adults employ (Greene, 1997). (Conant and Collins, 1998; Greene, 1997; Harding, 1997)

Communication and Perception

As with many snakes, vision and olfaction are important percptual channels for racers.

Food Habits

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). (Conant and Collins, 1998; Greene, 1997)

  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • eggs
  • insects
  • terrestrial non-insect arthropods

Predation

Racers are eaten by birds, dogs, cats, and coyotes.

Ecosystem Roles

Coluber constrictor is a mid-level predator, eating many kinds of smaller animals, but in turn eaten by larger predators.

Economic Importance for Humans: Positive

Racers are beneficial to humans in that they destroy rodent and insect pests (Harding, 1997). (Harding, 1997)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

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

Conservation Status

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). (Harding, 1997)

Other Comments

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). (Harding, 1997; Morris, 1944)

Contributors

George Hammond (editor), Animal Diversity Web.

Angie Hastings (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

agricultural

living in landscapes dominated by human agriculture.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

Conant, R., J. Collins. 1998. Reptiles and Amphibians: Peterson Field Guides. 3rd Ed.. New York: Houghton Mifflin Company.

Ernst, C., R. Barbour. 1998. Snakes of Eastern North America. Virginia: George Mason University Press.

Greene, H. 1997. Snakes: The Evolution of Mystery in Nature. California: University of California Press.

Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, MI: University of Michigan Press.

Morris, P. 1944. They Hop and Crawl. PA: The Jaques Cattell Press.