The Black Rat Snake is one of the most common snakes in the eastern United States. A
non-venomous snake, the Black Rat Snake grows to around 5 feet long, and is broader than the similar
Black Racer and
Coachwhip. The Yellow Rat Snake is a subspecies of the same species. Three guesses as to what color it is, and the first two don't count.
Rat snakes are constrictors, distant cousins of the much larger Boas and Anacondas, except without the crappy J-Lo/Ice Cube movies. As the name suggests, it feeds primarily on rats and similar small critters. It catches the rat it its mouth and quickly coils around its victim, killing it through suffocation. Suprisingly, although cats are often kept around as mousers, to control pests, most people do not keep rat snakes around, although they serve much the same purpose.
Scientific name: Elaphe obsoleta
Scientific name from http://www.snakesandfrogs.com/scra/snakes/scsnake.htm