The Black Rat Snake, genus Elaphe, species obsoleta, but also referred to by some taxonomists as Pantherophis alleghaniensis, is one of Kentucky’s largest snakes.
An article posted on the Live Science website explained the scientific name differences.
Until the early 2000s, both Old and New World rat snakes were generally thought to belong to the same genus, Elaphe, according to Alan Savitzky, a professor of biological sciences at Utah State University who specializes in the biology of snakes.
“There was a time not that long ago when all rat snakes were considered closely related,” Savitzy said. “We know now that the rat snakes in North America are more closely related to the king snakes than the Old World rat snakes.”
New technologies in molecular evolutionary studies have enabled scientists to look at the DNA differences between snakes. In 2002, herpetologist Urs Utiger published findings in the Russian Journal of Herpetology and proposed reclassifying North American rat snakes as members of the genus Pantherophis.
Color and Size
Coloration varies, but usually shiny brown to black, sometimes grayish. Older adults are often nearly all black. The head is slim, with a round eye (Photo by Henry Hartley)
The Black Rat Snake is a common, non-venomous constrictor that can reach 6 feet in length or more as an adult, and typically weighs 1 1/2 to 2 1/2 pounds.
Coloration varies, but usually shiny brown to black, sometimes grayish. Older adults are often nearly all black. The head is slim, with a round eye.
There’s a cream or yellowish coloring “between” its scales, and the belly is a light color, usually with black and white checkering. Young are grayish with darker blotches (saddles) down the back clearly extending onto the tail.
They may act aggressively when cornered, coiling up in a menacing posture, and sometimes expel a bad-smelling musk when confronted by a predator or picked up by a person.
Geographic Range and Distribution
Found statewide in Kentucky, the Black Rat Snake’s geographic range extends throughout most of the eastern U.S., from New England, south to Georgia, west to northern Louisiana, and as far north as southern Wisconsin.
Species closely related to the Black Rat Snake include the Texas Rat Snake, Yellow Rat Snake, Red Rat Snake, and Gray Rat Snake.
In rural Kentucky the Black Rat Snake is often encountered around abandoned farm houses, sheds, out buildings and barns, where they hunt for rats, mice, chipmunks, voles, and lizards (Photo provided)
Habitat and Food Habits
There’s a strong correlation between the habitats this snake prefers and what it eats.
In rural Kentucky, the Black Rat Snake is often encountered around abandoned farmhouses, sheds, outbuildings and barns, where they hunt for rats, mice, chipmunks, voles, and lizards.
When they live in woodlands, they often climb high up into trees, raiding nests to eat adult birds, young nestlings or bird eggs. They also enter birdhouses to eat young birds or bird eggs in the nest.
Prey is killed by constriction, then swallowed head first.
They are mostly nocturnal, but are out during daylight hours too, especially early and late in the day. They sometimes are found lying in the sun during the spring.
All of Kentucky’s snake species hibernate during the cold weather months and usually come out in mid-to-late April unless March is unusually warm.
When cornered the Black Rat Snake may vibrate its tail in an attempt to trick a predator into confusing them for a rattlesnake. “This type of mimicry, where a harmless species mimics a harmful species, is known as Batesian mimicry,” said Bill Heyborne, a herpetologist, and professor of biology at Southern Utah University.
While it may be helpful in keeping predators away, Batesian mimicry can cause problems for rat snakes. Humans often kill them thinking they are venomous rattlers.
Young Black Rat Snakes are especially vulnerable to predations by hawks, owls, foxes, coyotes and raccoons.
Adults are frequently run over by vehicles when crossing highways.
Reproduction
The Black Rat Snake is a common, non-venomous constrictor in Kentucky that can reach 6 feet in length or more as an adult, and typically weighs 1 1/2 to 2 1/2 pounds (Photo provided)
Rat snakes reach sexual maturity in their fourth year.
Mating season is in the spring. Males attract females through pheromones.
Rat snakes are oviparous, meaning they lay eggs that spend little to no time incubating inside the mother.
If conditions are right, females may lay two clutches of eggs per year. Females typically lay clutches of about 12 to 20 eggs in a hidden spot, such as in a hollow log or loose soil covered with leaves.
The young hatch after about two months. There’s no parental care to their young. Baby rat snakes are about 12 to 13 inches long when they hatch, with a distinctive gray and black pattern characteristic of juveniles.
Throughout the ages, snakes have been mercilessly persecuted. But, collectively, they play a beneficial role in nature.
Kentucky has four species of venomous snakes and 29 species of non-venomous snakes.
The University of Kentucky, College of Agriculture, posts information and photographs of Kentucky snakes on these web pages: http://www2.ca.uky.edu/forestryextension/kysnakes/
The Black Rat Snake is an accomplished tree climber and valuable predator in farm country, one of Kentucky’s most common snakes, that can grow to an impressive size.
Art Lander Jr. is outdoors editor for KyForward. He is a native Kentuckian, a graduate of Western Kentucky University and a life-long hunter, angler, gardener and nature enthusiast. He has worked as a newspaper columnist, magazine journalist and author and is a former staff writer for Kentucky Afield Magazine, editor of the annual Kentucky Hunting & Trapping Guide and Kentucky Spring Hunting Guide, and co-writer of the Kentucky Afield Outdoors newspaper column.
