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Black Rat Snake

Order: Squamata
Family: Colubridae
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 are similar.

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, and Louisiana.

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 flat farmland.

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.

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.

Life Span

There is no special status for the rat snake.

Fun Facts
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 human persecution.

Source of Information
All or part of this information was provided by 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.

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