The relationship between a Corn Snake and a Rat Snake is a common point of confusion in snake taxonomy. Common names often group species that share general characteristics, making “Rat Snake” an umbrella designation. Scientific classification uses a precise, hierarchical system to define specific species and their exact relatives. Understanding the connection requires examining the scientific genus that links these reptiles, clarifying that one name refers to a broad group and the other to a distinct species within it.
Defining the Rat Snake Group
The term “Rat Snake” in North America primarily refers to snakes belonging to the genus Pantherophis. This genus encompasses a group of non-venomous constrictors found across the central and eastern United States. These large, terrestrial reptiles share physical and behavioral traits, including a diet largely consisting of rodents and other small mammals.
Historically, these species were classified under the Old World genus Elaphe. Molecular studies in the early 2000s confirmed the North American species were distinct, leading to the resurrection of the genus Pantherophis. Physical commonalities include a divided cloacal plate and weakly keeled dorsal scales. This taxonomic group solidified “Rat Snake” as the common name for these New World constrictors.
The Specific Classification and Identity of the Corn Snake
The Corn Snake is classified as a type of Rat Snake because its scientific name is Pantherophis guttatus. As a member of the Pantherophis genus, it shares the fundamental characteristics of the group, such as being a powerful, non-venomous constrictor. It is sometimes referred to regionally as the Red Rat Snake, further indicating its place within the broader category.
The species is known for its relatively slender build and distinct color pattern. The background color is typically orange or brownish-yellow, overlaid with large, reddish-orange blotches outlined in black. A unique feature is the presence of a spear-point or V-shaped pattern on the top of the head.
The common name, Corn Snake, likely has two debated origins. One theory suggests the name came from the snake’s frequent presence near corn storage barns, where it hunted rodents. The second theory points to the snake’s ventral (belly) scales, which display a distinctive black and white checkerboard pattern resembling corn kernels.
Distinguishing the Corn Snake from Other Rat Snake Species
While the Corn Snake is a Rat Snake, it is a separate species from its relatives within the Pantherophis genus, distinguishable by its unique color palette and markings.
Size and Range
The Eastern Rat Snake (Pantherophis alleghaniensis) is often considerably larger than the Corn Snake. Adults of the Eastern species can reach over eight feet in length, while Corn Snakes typically max out around six feet. The Western Rat Snake (Pantherophis obsoletus) is found west of the Mississippi River.
Coloration and Pattern
Adult Eastern Rat Snakes frequently exhibit a uniform black or dark brown coloration over most of their range, or yellow with dark longitudinal stripes in the Florida peninsula. The Western Rat Snake is also typically darker, often appearing black with a lighter background. The Texas Rat Snake, a variant, usually has a brown-to-black base with hints of red or orange.
In contrast, the Corn Snake’s bright orange or reddish-brown base color and specific, black-bordered blotches are consistent identifiers. The unique combination of the spear-point head pattern and the striking black-and-white checkerboard belly pattern reliably separates Pantherophis guttatus from its cousins.