REPTILES OF THE METRO AREA
METROPOLITAN  NATURALIST
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Black Racer (Coluber constrictor constrictor)

The Black Racer is a very active snake, often seen as a black streak darting across the trail.
The young Racer is camouflaged in the forest by a pattern of brown blotches on a grey
background, very similar to the Black Rat Snake young. As the snake matures it becomes solid
black above and below except for a white chin. These snakes can reach over 5 feet in length.

Another large black snake in our area that could be confused with the Black Racer is the
Black
Rat Snake. The young of both species have brown blotches on a grey background. Both snakes
lose the blotched pattern and become black as they mature. These two snakes can be
distinguished by their body shape, coloration, and behavior. The Black Racers' scales are
smooth, while the Rat Snakes have keeled scales. The Black Racers tend to be nervous and
very active snakes, while Rat Snakes tend to be slower moving. The Black Racers' body is
round in cross section, while the Rat Snake's body shape is often described as being like a loaf
of bread with a rounded top and a flattened belly. The Black Rat Snake retains a white
chain-like pattern on its back and white on it's belly through adulthood, while the adult black
racer is usually solid black except for a white chin.

This snake has a varied diet including rodents, frogs, even fish, and other snakes. A black racer
I caught at
Lake Roland once regurgitated a Hognosed Snake when I caught it. These snakes
are usually difficult to catch and to handle, being very fast moving and aggressive when caught.

Black Racers can be particularly aggressive during breeding. I came across a pair mating on the
side of a trail near Lake Roland on a warm spring day several years ago. When I approached,
one of the snakes actually advanced toward me, striking and vibrating its tail as though
defending its mate. I imagine this would have been a frightening experience for someone less
familiar with snakes.

These snakes are non-venomous but are quick to bite when captured and have small, sharp
teeth that can cause a somewhat painful and bloody bite. Although these snakes are reported
to have a Duvernoy's gland*, it appears that no adverse reactions have been reported from
their bite in humans. The role of Duvernoy's gland secretions in prey acquisition needs more
study. Since these snakes are not constrictors it seems likely that these secretions might play a
role in killing or paralyzing prey animals.
Northern Black Racer (Coluber constrictor)
Northern Black Racer (Coluber constrictor)
Northern Black Racer (Coluber constrictor)
Northern Black Racer (Coluber constrictor)
Northern Black Racer (Coluber constrictor)
Northern Black Racer (Coluber constrictor)
This Black Racer was sunning on the side of a trail in Baltimore County on a spring afternoon. The temperature was
about 60 degrees F. Black Racers are occasionally seen out and about when the temperature is too cold for most
other snakes. A high metabolism might help them generate heat to help them stay active at temperatures to low for  
most slower moving snakes.
This snake is "tasting" the air with his forked tongue. The tips of the tongue are waved in the air to sample chemicals from the
air. The two tips then are inserted in a specialized organ, called the Jacobson's organ, in the roof of the snakes mouth to smell
the air.
The underside of a Black Racer. A white liquid, called musk, can be seen coming from the base of the tail and running
down the tail. Musk is an unpleasant smelling liquid that the snake releases when it is agitated. The unpleasant smell
might make the snake less palatable to predators. The oily musk tends to stick to the hands when a racer is handled and
can be difficult to wash off.