Northern Black Racer
Coluber constrictor constrictor

** Harmless **

  • Northern Black Racer
  • Northern Black Racer
  • Northern Black Racer
  • Northern Black Racer Juvenile
Northern Black Racer1 Northern Black Racer 2 Northern Black Racer3 Northern Black Racer Juvenile4

Common Name: Northern Black Racer
Scientific Name: Coluber constrictor constrictor
Etymology:
Genus: Coluber is Latin for "snake".
 Species: constrictor is derived from the Latin words con which means "together" or "with" and strictus which means "drawn together" or "tight".
 Subspecies: constrictor is derived from the Latin words con which means "together" or "with" and strictus which means "drawn together" or "tight".
Vernacular Names: American black snake, American racer snake, black chaser, black runner, blue racer, chicken snake, cow sucker, green snake, hoop snake, horse racer, slick black snake, true black snake, white-throated racer.
Average Length: 36 - 60 in. (90 - 152 cm)
Virginia Record Length:  70.7 in. (179.5 cm)
Record length: 73 in. (185.4 cm)

 

PHYSICAL DESCRIPTION: 10-60 in. long *1101*; slender; black above and below, usually with very little white on chin and throat; scales smooth *882*; In Virginia, maximum known SVL is 1395 mm (54.0 in.) and total length is 1795 mm (70.7 in.). Tail length/total length ratio averages 23.3+/-2.1% (15.3-29.1, n=143). Adult length is usually 36-60 inches, and the record length is 78 inches *11523*. Coloration and pattern: body of adults slender and uniformly light gray; head black except for a anterior portion of snout which is brownish; chin and a variable portion of the venter of the neck are white; some white pigment occurs on supralabial scales in some individuals; racers in shedding cycle appear dark gray to light brown.*10760*

SEXUAL DIMORPHISM: Black racers show little sexual dimorphism.*10760*

JUVENILES: Upon hatching, juveniles have a dorsal pattern of dark gray to brown body. The venter is cream in color any may be plain or bear an irregular series of black dots. Small black or brown dots often occur laterally on the dorsum. the chin is plain white and the head is mostly brown interspersed with varying amounts of gray. The venter of the tail is plain white. The juvenile pattern becomes occluded with age; the melanin becoming so abundant that all but the light chin and brown snout is obscured. This pattern is lost by about age three and at a SVL of about 300 mm. Virginia hatchlings averaged 224.7+/-8.4 mm SVL (206-235, n=28), 298.3+/-11.5 mm total length (275-315) and 6.3 g (avg. for one litter) body mass.*10760*

CONFUSING SPECIES: Adults of this species are often confused with adult eastern ratsnakes, however, the latter has a breadloaf-shaped body in cross section, keeled scales middorsally, and varying amounts of white on the flat venter. Juvenile Eastern Ratsnakes have an eye-jaw stripe, a checkerboard pattern on the venter, and usually, irregular blotches with anterior and posterior projections on the corners. Black phase Heterodon platirhinos are short and stocky compared to C. constrictor and they have a broader head with an unturned snout.*10760*

GEOGRAPHIC VARIATION: Little geographic variation is exhibited by C. constrictor in Virginia.*10760*

REPRODUCTION: Mates in May *1101*; eggs laid June *1008*,1014*; July *1014,1101*; August *1101*; hatch in mid-July to mid-August *1008*; 4-25 eggs/clutch *1014*; 12-36 eggs/clutch*10760*; eggs laid under logs, under mattresses, rocks, sheet metal, and other objects, in rodent tunnels, and in mulch and sawdust piles.*10760* Known egg-laying dates are between 24 May and 26 June. Eggs averaged 29.5+/-3.2 x 20.5+/-1.7 mm in size and weighed an average of 7.2+/-0.7 g.*10760*; eggs often become lumpy or irregular and discolored by dirt during incubation *1008*; hatchlings are about 290 mm long *1014*; hibernation: emerges from hibernation around first of April *1008*;

BEHAVIOR: arboreal; can burrow *1008*; diurnal *1014*; often retreats upward into bushes or low branches of trees when closely pursued *882*; nervous, irritable, fast moving; will strike and bite when cornered; not a constrictor *1013* Stan Alford observed this species breeding on April 9 and April 22. Jeff Beane observed this species breeding on May 8, 14, and 18 *11523*.


References for Life History

Photos:

*Click on a thumbnail for a larger version.

Adult - Chesapeake Adult - Chesapeake Adult - Loudoun Co. Adult - Fauquier Co. Adult - Fairfax Co. Subadult
Prince William Co.
 
Juvenile - Prince William Co. City of Danville Bedford Co.   A juvenile black racer eating a northern brown snake.
Chesterfield Co.
 

 

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