Any of 40–55 snake species in the genus Elaphe (family Colubridae) and similar forms, found in woodlands and barnyards in North America, Europe, and Asia. Nonvenomous, they kill rats and mice by constriction, and also eat eggs and poultry. Some hunt birds in trees. These egg-laying snakes are normally slow and docile, but in self-defense they vibrate the tail, discharge a foul liquid, and strike from an upreared position. The black rat, or pilot black, snake (E. obsoleta obsoleta) of the eastern U.S. may exceed 8 ft (2.5 m).