Black Rat Snake
Genus/species: Elaphe obsoleta obsoleta
The common rat snake is medium-sized, averaging 42 to 72
inches (106.7 to 183 cm) in length. At the widest point
of the snake's body, its average diameter is 1.5 inches
(3.8 cm). The rat snake is covered with keeled scales,
and has a powerful slender body with a wedge-shaped head.
The anal plate of the common rat snake is divided. A variety
of subspecies is found across the United States.
The black rat snake, as the name implies, is completely
black except for a white chin. Hatchlings of the black
rat snake have a pale grey background with black blotches
along the back. As the snake matures, the color becomes darker
until the snake reaches its adult phase. Hatchlings are
often mistaken for copperheads because their skin patterns
Common rat snakes tend to be shy and, if possible, will
avoid being confronted. If these snakes are seen and confronted
by danger, they tend to freeze and remain motionless. Some
adults attempt to protect themselves. They
coil their body and vibrate their tails in dead leaves to
simulate a rattle. If the snakes continue to be provoked,
they will strike.
Rat snakes produce a foul-smelling musk and release
it on the predator if they are picked up, spreading the
musk around with their tail. The musk acts as a deterrent.
A few of the rat snake subspecies tend to be more aggressive.
The Texas rat snake and the black rat snake are very snappy,
while the yellow rat snake is more passive. When alarmed,
the Everglades rat snake swims away through the swampy waters.
Rat snakes are excellent swimmers.
Distribution and Habitat:
Rat snakes are found from New England south through Florida
and west through the eastern half of Texas and Nebraska
and north again to southern Wisconsin. The black rat snake
is the most widely distributed common rat snake with a
range from New England south through Georgia and west
across the northern parts of Alabama, Mississippi, and
Louisiana, and north through Oklahoma to southern Wisconsin.
There is also an isolated population in southern Canada
and northern New York.
The yellow rat snake is found along the coast of the Carolinas
south through Georgia and Florida. The Everglades rat snake
has an isolated population in southern Florida's Everglades.
The gray rat snake ranges from southern Georgia and northern
Florida west through Mississippi and north to southern Kentucky.
The Texas rat snake can be found in southern Oklahoma, Texas,
Common rat snakes live in a variety of habitats with each
subspecies preferring a slightly different one. Some
of these habitats overlap with one another. Common rat snakes
are excellent climbers and spend a lot of time in trees.
Black rat snakes live at elevations from sea level
to high altitudes in the Appalachian Mountains. Black rat
snakes live in habitats ranging from a rocky hillside to
Diet in the Wild:
Rat snakes are primarily known as rodent eaters, however
other food preferences do exist. As juveniles, rat snakes
eat small lizards, baby mice, and an occasional small
frog. Adult rat snakes have a diet mainly consisting of
mice and rats, but also include chipmunks, moles,
and other small rodents. Adults also eat bird eggs
and young. Rat snakes kill their prey by constriction.
They are fed mice, chicks, and rats.
Like most snakes, rat snakes are egg layers. Between March
and May, snakes begin to emerge from their winter hibernation.
After a few weeks, they begin to seek out a mate,
typically in late April, May, and early June. Males tend
to wait for the females to pass through their territory,
and, by using pheromones, communicate and initiate
the mating process with the female. The male snake
approaches the female, lines up with her, and attempts
to wrap his tail around hers with their vents nearly touching.
Some males grasp the female with the mouth,to hold
her in place and prevent her from moving away.
The male then erects his hemipenes and inserts it into
the female's cloaca while several small spines anchor the
hemipenes firmly. Mating may last only a few minutes or
span a few hours.
Five weeks later, the female lays 12 to 20 eggs.
The eggs are laid in a hidden area, under hollow logs or
leaves, or in abandoned burrows. The eggs hatch 65 to
70 days later. The hatchlings of common rat snakes are vigorous
eaters and double their size rather quickly. If conditions
are good, females sometimes produce two clutches of
eggs a year.
There is no special status for the rat snake.
Rat snakes are very useful around barns and in farming communities
because they help control pest populations. Their habitat
is slowly being reduced due to land development and the
cutting of trees. However, they continue to maintain a
healthy population. Due to people's lack of knowledge and
fear of snakes, rat snakes continue to be the victim of
Source of Information
All or part of this information was provided by the Animal Diversity Web and Museum of Zoology of the University of Michigan.
It appears here with their permission. The original author of this information was Patrick Trepanowski.
For more information, including references, see the Animal Diversity Web account for this species, here:
http://animaldiversity.ummz.umich.edu/ site/ accounts/ information/ Elaphe_obsoleta.html.