Rat Snake Facts
Black rat snakes are the largest species of rat snake.
Credit: J.D. Wilson / Savannah River Ecology Laboratory


Rat snakes are medium-to-large, nonvenomous snakes that kill by constriction. They pose no threat to humans. There are Old World (Eastern Hemisphere) and New World (Western Hemisphere) rat snakes, and the two types are fairly different genetically. 

New World rat snakes are found throughout North America. One species of rat snake is the corn snake, a docile animal and popular pet. As their name implies, rats are one of their favorite foods. 

In the past two decades, the question of what is a rat snake has become increasingly complicated to answer. 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, Savitzy told Live Science. This has caused a great deal of upheaval in snake classification, and snakes are being moved into different genera. 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.

The proposal met with mixed reactions. Some authorities adopted the classification. For example, the Global Biodiversity Information Facility (GBIF), a collaborative network of researchers, accepts Pantherophis, as does the Society for the Study of Amphibians and Reptiles (SSAR), an international non-profit organization that supports herpetological research and education.

However, the International Commission on Zoological Nomenclature (ICZN), recognized as the arbiter for the correct use of the scientific names of animals, does not recognize Pantherophis; nor does the Convention on International Trade in Endangered Species (CITES). TheIntegrated Taxonomical Information System (ITIS), a partnership of organizations that provides taxonomic information, lists Pantherophisspecies as "invalid." 

According to Reptiles Magazine, rat snakes can vary widely in appearance. They can have blotches, stripes, a combination of both, or be single-colored. They can be black, red, brown, yellow, gray or black-and-white colored. They have keeled scales, slender bodies, and wedge-shaped heads, according to the Smithsonian National Zoological Park. Their pupils are round, as are most nonvenomous snakes'. 

Some species of rat snakes reach lengths of 10 feet, though 4 to 6 feet long is more common, according to the Smithsonian National Zoological Park. 

The following is a description of some common rat snake species' appearances.

Eastern rat snake/black rat snake
(Elaphe obsoleta or Pantherophis alleghaniensis)

According to the Virginia Department of Game and Inland Fisheries, this is a shiny, primarily black snake. It has a white chin and many animals have white bellies. When their skin is stretched, such as after a meal, a spotted pattern may be visible. Spots might be white, yellow, red or orange. Bellies are sometimes checkered in gray, brown, white or yellow. Juveniles are blotchier and have white or gray bodies. 

Texas rat snake
(Elaphe obsoleta lindheimeri or Pantherophis obsoleta lindheimeri)

According to the University of Texas at Arlington’s Amphibian and Reptile Diversity Research Center, these commonly found snakes often grow more than 6 feet long. Their coloration varies somewhat by location, with snakes in eastern Texas being greyer while those in central Texas being yellower. All Texas rat snakes have reddish orange skin beneath their scales. They tend to have white or grey bellies and grey heads. Texas rat snakes have splotchy patterns.

Yellow rat snake
(Elaphe obsoleta quadrivittata or Pantherophis alleghaniensis quadrivittata)

According to the Cincinnati Zoo, yellow rat snakes are the most common rat snake in the Florida peninsula. This is a morph of the eastern rat snake/black rat snake with all-over yellow or orange coloring. They typically have four narrow brown stripes going down their backs and yellow irises. 

Red rat snake
(Elaphe guttatus or Pantherophis guttatus)

According to Savitzky, "red rat snake" is an old-fashioned synonym for corn snake. Red rat snakes vary in color but have yellowish or orange bodies with large red blotches on their backs, dark marks on their bellies, and a V shape on the tops of their heads. 

Gray rat snake
(Pantherophis spiloides or Elaphe spiloides)

According to Ontario Nature, gray rat snakes are the largest snakes in Canada at up to 7 feet in length. They have grayish coloring with black or dark gray blotches on their backs and bellies. Juveniles are vividly patterned, but that fades somewhat with adulthood. 

Yellow rat snakes are the most common rat snake in Florida.
Yellow rat snakes are the most common rat snake in Florida.
Credit: J.D. Wilson / Savannah River Ecology Laboratory


Rat snakes are found throughout North America, from Central America to Southern Canada. Their habitats vary by species. The following is a list of some common rat snake species' ranges and habitats. 

Eastern rat snake/black rat snake
(Elaphe obsoleta or Pantherophis alleghaniensis)

The largest species of rat snakes, this snake lives throughout New England and south to Georgia. They are found as far west as Northern Louisiana and as far north as Southern Wisconsin. They can live in a variety of forests and grasslands but according to Penn State University, a deciduous forest surrounded by grass is probably ideal. 

Texas rat snake
(Elaphe obsoleta lindheimeri or Pantherophis obsoleta lindheimeri)

As its name implies, Texas rat snakes are found throughout Texas, though they are also encountered in Louisiana, Oklahoma and Arkansas. According to the University of Texas at Arlington, they can live in a wide variety of habitats, including forests, grasslands, suburbia and urban areas. 

Yellow rat snake
(Elaphe obsoleta quadrivittata or Pantherophis alleghaniensis quadrivittata)

According to the Cincinnati Zoo, these snakes are found along the coasts of North and South Carolina, Georgia and Florida. They live in pine flatlands and shrubs, forests and cypress swamps, as well as citrus groves, abandoned buildings and pastures.

Red rat snake
(Elaphe guttatus or Pantherophis guttatus)

These snakes are found throughout the southeastern United States, particularly in Florida. They live in pine flatlands, mangrove swamps, forests and urban areas, according to the Florida Fish and Wildlife Conservation Commission

Gray rat snake
(Pantherophis spiloides or Elaphe spiloides)

Gray rat snakes are found in the central United States, from Indiana to Florida and west to the Mississippi. They are also found in southern Ontario. According to Ontario Nature, gray rat snakes spend their time in forests, venturing out into grassy areas when it is warm enough.

Rat snake behavior varies among species. Some species, such as the black rat snake/eastern rat snake, are known to be shy but somewhat snappish and aggressive when cornered, according to Marshall University. They produce a bad-smelling musk when touched by a predator or picked up by a person, and spread it around with their tail. On the opposite end of the spectrum are corn snakes, some of the most docile serpents around. 

All species of rat snakes may vibrate their tails in 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.

Rat snakes are semi-arboreal, said Savitzky. While they are nocturnal in warm areas, they are still seen during the day fairly frequently. You may see them lying out in the sun or foraging in the forest or on the plains. They also take shelter in tree cavities to wait for prey. Rat snakes are often found in barns, where farmers like them to eat rodents.

Rat snakes are excellent swimmers, and the Everglades rat snake is known for swimming away from predators, according to the Smithsonian National Zoological Park. 

In cold climates, rat snakes hibernate in the winter, according to Marshall University. 

Rat snakes are constrictors, said Savitzky. They squeeze their prey to death and swallow it whole. There are some common misconceptions about how constricting works, said Heyborne. One is that constrictors crush or break the bones of their prey. Another is that they suffocate it, squeezing the prey's lungs too tightly to work. "It turns out that the squeezing overwhelms the circulatory system," explained Heyborne. "Blood cannot get to the brain, and the animal dies within seconds due to ischemia."

Rat snakes often feed on small rodents, such as mice, rats, chipmunks and voles, but they are also known to eat frogs, lizards, birds and bird eggs. Juveniles are more likely to eat cold-blooded prey, while adults stick almost exclusively to warm-blooded animals, according to Marshall University. Some species of rat snake are called chicken snakes because they like to eat chicken eggs. 

Rat snakes are known to both wait for and ambush their prey and to actively forage for it, according to Savitzky. 

According to Penn State University, sometimes after killing their prey, rat snakes continue hunting. They do this because they are cloaked in the prey's scent so other prey is less likely to notice them. They might kill more prey and then return to the original kill. Therefore, rat snakes may eat many animals in a single meal.

Rat snakes are oviparous, meaning they lay eggs that spend little to no time incubating inside the mother, said Savitzky. If conditions are right, females may lay two clutches of eggs per year. Otherwise, they usually lay one. In cold climates, they may lay eggs less frequently. 

Mating season is often in the late spring, though it depends on the climate. Males attract females through pheromones and will sometimes fight other males for the same female, according to Penn State University.

Five weeks later, females lay clutches of about 12 to 20 eggs in a hidden spot, such as in a hollow log or pile of compost. According to Penn State University, the burying beetle is a common parasite of rat snake eggs. The beetle lays its eggs in the snake eggs, and the baby beetles eat the snake embryos. 

The young hatch after about two months. Rat snakes offer no parental care to their young. Baby rat snakes are quite long, around 13 inches (33 centimeters). They are often eaten by hawks and other snakes. 

Rat snakes' lifespan is unknown, according to the Smithsonian National Zoological Park.

Some species of rat snakes are endangered. Canadian grey rat snakes are either endangered or threatened depending on the location. Eastern/black rat snakes are considered endangered in Massachusetts, and red rat snakes are considered endangered in the Florida Keys.