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Eastern Yellowbelly Racer
Coluber constrictor flaviventris
Status
The Racer is listed as a species of Special
Concern by the Minnesota Department of Natural Resources (Moriarty,
1996).
Description
This is a large Minnesota species measuring
between 23 and 50 inches in length (Conant and Collins, 1991).
Adults are uniformly blue, bluish black, greenish, or light
brown. There are no head or dorsal markings. The undersurface
is dirty white, porcelain, or yellow with no markings. The
throat and neck are bright yellow and the chin and upper labials
may be yellow or white. This is one of the few Minnesota snakes
that go through a remarkable ontogenetic color and pattern
change. The young are vividly marked above and below having
a white or gray ground color with black, brown, or reddish
blotches. Their bellies are white with small brown or reddish
spots. They lose these markings and develop adult coloration
in one to two years. Racers have smooth scales and divided
anal plates.
Subspecies
Of the nine subspecies of Racers in the
United States (Collins, 1997), only one, the Eastern Yellowbelly
Racer (Coluber constrictor flaviventris), is found in Minnesota
(LeClere, 1996). This serpent is also referred to as the Blue
Racer.
Range
The Racer is found in southeastern and
some of southcentral Minnesota in suitable habitat along much
of the Mississippi and parts of the Minnesota River Valleys.
Habitat
Racers prefer open prairie, woodland edge,
and bluff prairies. They live in fields, grasslands, and railroad
grades adjacent to these habitats.
Habits
Racers are the quickest snakes in Minnesota
and also our most visually oriented. They are active hunters,
moving quietly through grass and brush in search of food.
They are diurnal even in hot weather. This thermoregulatory
habit enhances their ability to chase down and capture fast
moving prey. When they feel threatened, they can flee with
incredible speed. They seem to have good home range orientation
as they will slither, often toward an intruder, and zip into
a preferred hiding spot. When cornered, they may raise their
head, strike, and vibrate their tails, (which turns out like
a rapid tail wagging when compared to Rat, Bull, or Fox Snakes).
Generally, if they are picked up, they will musk, defecate,
and bite by striking and chewing with their long teeth. But,
I have seen some specimens curl up in a ball and hide their
head in their coils. I have observed this behavior on hot
and cool days alike. On cool rainy days, Racers may be found
hiding under rocks, logs, boards, or in rocky crevices. They
are active from mid April to October (Blasus, 1997) and hibernate
below the frost line often with other species of snakes such
as Garter Snakes, Milk Snakes, Bull Snakes, Timber Rattlesnakes,
Fox Snakes, and other Racers. They breed in spring, and the
female lays 5-25 rather granular feeling eggs which hatch
around late August.
Food
This snake probably has the most diverse
eating habits of any Minnesota snake. They will eat about
anything they can chase down. Food items include: rodents,
insects, frogs, toads, lizards, snakes, reptile eggs, birds,
and birds' eggs. They are not constrictors, but they may use
a loop or two of their coils to press victims to the ground.
Large prey are shaken violently and rapidly chewed upon with
the Racers' strong jaws, while smaller food is simply swallowed
alive. I have found the fecal matter of many wild Racers are
comprised largely of locust exoskeletons (LeClere, 1996).
Many people have witnessed Racers chasing and consuming Six-lined
Racerunners (not an easy task), and other snakes. On two occasions,
young Fox Snakes were being consumed by Racers when they were
discovered (Jessen, 1993; Bergquist, pers comm.) and a large
Eastern Garter Snake on another (Lydon, pers comm.). Young
Racers have been seen eating small Brown and Red-bellied Snakes
(LeClere, pers obs.).
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