Rat Snakes range between 3.3 ft. As the common name infers, the dorsal coloration of the Black Rat snake is black. Some specimens are solid black, some have faint blotches on the their dorsum, and others' dorsums are patterned with light flecking between the scales.
Juveniles have dark dorsal patterns on light gray backgrounds.
The ventral side of these snakes is white or gray and frequently it is mottled with gray. Yellow Rat Snakes are similar to Black Rat Snakes in all respects except for dorsal coloration. Their dorsal coloration is greenish or greenish-yellow and four dark stripes run along the length of its body. Black Rat Snakes are common in the mountains and Piedmont. They interbreed with Yellow Rat Snakes in the northeastern Coastal Plain.