Do snakes eat snakes?

King snakes are particularly fond of eating other snakes althogh they do not out of their way to track them down. A chance encounter with another species usually results in the king snake overcoming the other by constriction. King snakes are immune to the venom of poisonous snakes and so even such deadly species as rattlesnakes and copperheads are not safe from them. King snakes are protected in some areas, for their snake eating habits are considered useful.