Rat snakes are found from New England south through Florida and west through the eastern halves of Texas and Nebraska and north again to southern Wisconsin (Staszko and Walls 1994). Elaphe obsoleta obsoleta (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. E. o. quadrivittata (Yellow Rat Snake) is found along the coast of the Carolinas south through Georgia and Florida. E. o. rossalleni (Everglades Rat Snake) has an isolated population in southern Florida, hence, where the Everglades are located. E. o. spiloides (Gray Rat Snake) ranges from southern Georgia and northern Florida west through Mississippi and north to southern Kentucky. E. o. lindheimerii (Texas Rat Snake) can be found in southern Oklahoma, Texas, and Louisiana (Conant and Collins 1998).

Biogeographic Regions: nearctic (Native )

endemic to a single nation

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: As defined by Burbrink (2001), the range of E. obsoleta is as follows: west of the Mississippi River from southern Louisiana along the Gulf Coast to southern Texas, west to central Texas on the Edwards Plateau, and through Oklahoma, central and eastern Kansas, southeastern Nebraska, and southeastern Iowa to extreme southeastern Minnesota.

The common rat snake is medium-sized, averaging 42-72 inches (106.7-183 cm) in length (Conant and Collins 1998). At the widest point of the snake's body, the average diameter is 1.5 inches (3.8 cm) (Staszko and Walls 1994). Covered with keeled scales, common rat snakes have a powerful slender body with a wedge-shaped head (Mattison 1990). At the middle of the snake's body, there are 29 or fewer scale rows. In most rat snakes, there are 8 supralabials, and over 220 ventral scales, with 70 to 100 subcaudals (Staszko and Walls 1994). The anal plate (scale) of the common rat snake is divided. These snakes come in a variety of subspecies, each of which will be briefly described here.

The black rat snake, as the name states, is completely black except for their white chin. Hatchlings of the black rat snake have a pale grey background with black blotches along its back. As the snake matures, the color becomes darker until the snake reaches its adult phase. (Conant and Collins 1998)

The yellow rat snake has four well-defined longitudinal stripes extending down the length of its back. The base color varies from dull to bright yellow. The tongue, of the yellow rat snake, is black. Hatchlings are similar to those of the black rat snake, however, as the hatchlings mature, the dark spots fade as the yellow coloration and longitudinal stripes become more prominent. (Conant and Collins 1998)

The Everglades rat snake has a bright orange ground color. In some specimens, the color may appear more orange-yellow. This rat snake has grayish longitudinal stripes, which are not well defined and are often hard to see. The tongue is red. Juvenile Everglades rat snake are a pinkish color. (Conant and Collins 1998)

The gray rat snake keeps the blotched juvenile pattern its entire life. The blotches will vary between dark gray and brown. Juvenile black and yellow rat snakes are often mistaken as juvenile gray rat snakes. (Conant and Collins 1998)

The Texas rat snake is similar to the gray rat snake, however the blotches are usually less defined. The head of the Texas rat snake is often black. The juveniles of this subspecies have a much darker gray ground color. (Conant and Collins 1998)

• Terrestrial

Common rat snakes live in a variety of habitats because each subspecies prefers a slightly different habitat. Some of these habitats overlap with one another. Common rat snakes are excellent climbers and will spend a lot of time in trees. Black rat snakes live at all elevations, from sea level to altitudes in the Appalachian Mountains. The black rat snakes lives in habitats ranging from a rocky hillside of mountains to flat farmland. The yellow rat snake is well established, living in oak hammocks, cut-over woods, fields, and around barns and abandoned houses. However, yellow rat snakes prefer a life in river swamps of the South, where they live high in cypress and other trees. Gray rat snakes replace the black rat snake in southern habitats suitable for black rat snakes. The Texas rat snake's habitat ranges from bayou and swampy areas to woods and stream valleys to rocky canyons. The Everglades rat snake makes its home in the Kissimmee Prairie and the Florida Everglades. In this habitat they can be found in trees and shrubs along the waterways, in the sawgrass, and on open prairies. (Conant and Collins 1998)

Terrestrial Biomes: taiga ; savanna or grassland ; forest

Rat snakes are primarily known as rodent eaters, however, other food preferences do exist. As juveniles, rat snakes will eat small lizards, baby mice, and an occasional small frog. Adult rat snakes have a diet mainly consisting of mice and rats, but will also include chipmunks, moles, and other small rodents. Adults will also eat bird eggs and young birds that do not put up a strong fight. Rat snakes kill their prey by constriction. (Rossi 1992)

Average lifespan

Status: captivity: 33.9 years.

Like most snakes, rat snakes are egg layers. Between March and May, snakes will begin to emerge from the winter's hibernation. After a few weeks, the common rat snakes will begin to seek out a mate, typically in late April, May, and early June (Rossi 1992). Males tend to wait for the females to pass through their territory, and by using pheromones, will communicate and initiate the mating process with the female (Rossi 1992). The male snake will approach the female, line up with her and attempt to wrap his tail around hers with their vents nearly touching. Some males will grasp the female, with his mouth, to hold her in place and prevent her from trying to move away. The male will then erect his hemipene and insert it into the female's cloaca while several small spines anchor the hemipene firmly (Staszko and Walls 1994). Mating can last only a few minutes or it can span the time of a few hours. Five weeks later, the female will lay around 12 to 20 eggs (Mattison 1990). The female will lay her eggs in a hidden area, under hollow logs or leaves, or in abandoned burrows. The eggs will hatch 65 to 70 days later. The hatchlings of common rat snakes are vigorous eaters and will double their size rather quickly. If conditions are good, females will sometimes produce two clutches of eggs a year. (Mattison 1990)

Range number of offspring: 12 to 20.

Average age at sexual or reproductive maturity (male)

Sex: male: 1460 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1460 days.

The subspecies Elaphe obsoleta obsoleta is listed as special concern in the state of Michigan. Their habitat is slowly being reduced due to land development and the cutting of trees. However, they continue to maintain a healthy population in many areas. Due to people's lack of knowledge and fear of snakes, rat snakes continue to be the victim of human persecution. (Harding 1997)

US Federal List: no special status

CITES: no special status

State of Michigan List: special concern

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Rat snakes are very useful around barns and in the farming community. These snakes should be welcome on farms because they help control the pest population (rodents). (Harding 1997)

Comments: Burbrink et al. (2000) and Burbrink (2001) examined genetic and morphological variation in Elaphe obsoleta and determined that the nominal subspecies do not represent evolutionary lineages and should no longer be recognized. Further, these authors identified three clades within E. obsoleta, corresponding to populations (1) west of the Mississippi River (western clade), (2) east of the Mississippi River and west of the Appalachian Mountains and Apalachicola River (central clade), and (3) east of the Appalachians and the Apalachicola River (eastern clade). Burbrink (2000) recognized the three clades as distinct species: E. obsoleta (western clade), E. spiloides (central clade), and E. alleghaniensis (eastern clade). In mapping the distribution of the species, Burbrink indicated a very large area of "taxonomic uncertainty" extending from New England to northern Georgia. In this region the distribution of E. alleghaniensis was deemed "somewhat questionable with regard to hybridization with members of Elaphe spiloides." Although Burbrink concluded that the molecular data show that E. alleghaniensis and E. spiloides represent independently evolving units with separate evolutionary histories and thus should be recognized as different species under the evolutionary species concept, contact zones were not critically examined, so the nature and dimensions of clade boundaries, and the precise distributions of alleghaniensis and spiloides along the length of the Appalachians, remain uncertain. Jensen et al. (2008, Amphibians and Reptiles of Georgia) mentioned Burbrink's proposed split but did not adopt it.

Molecular data indicate that Elaphe obsoleta lindheimeri, E. o. quadrivittata, and E. o. rossalleni are not distinct evolutionary lineages (Burbrink et al. 2000). The checklists by Crother et al. (2003) and Crother (2008) did not accept lindheimeri, quadrivittata, or rossalleni as valid taxa.

Elaphe bairdi, confirmed as a valid species by Burbrink (2001), was included in Elaphe obsoleta by some authors in older literature.

Utiger et al. (2002) examined mtDNA variation in New World and Old World "Elaphe" and determined that North American rat snakes currently included in the genus Elaphe form a monophyletic limeage that is distinct from Old World snakes that also have been regarded as Elaphe. They resurrected the genus Pantherophis for the rat snakes north of Mexico, including the following species: Pantherophis obsoletus (and P. alleghaniensis and P. spiloides, if one recognizes those taxa as species), P. guttatus, P. emoryi, P. vulpinus, P. gloydi, and P. bairdi. Based on mtDNA and nuclear DNA data, Burbrink and Lawson (2007) determined that New World Elaphe are not closely related to Old World Elaphe. Here we follow these studies and Crother (2008) and transfer New World Elaphe to the genus Pantherophis.