In the wild, king snakes feed on other snakes, lizards, turtle eggs, birds, frogs and small mammals. They are opportunistic feeders, meaning that their diet varies depending on what is available. Common king snakes are known for their immunity to pit viper venom, allowing them to feed on dangerous snakes like rattlesnakes and cottonmouths. King snakes use constriction to kill their prey before feeding.
In captivity, About.com recommends feeding king snakes mice or baby rats. In order to prevent injury, the snake should be fed prey that has been killed previously. The general rule is that the prey should be sized approximately equal to the snake at its widest point. It is common for king snakes to eat less in the fall and winter months.
King snakes give off an odorous musk as a defense mechanism when they are threatened. They also may vibrate their tail rapidly or bite. King snakes have a shiny black body with white or yellow lines and a black and yellow stomach. They usually reach between 3 to 6 feet in length. They tend to live near the margins of streams, marshes and swamps in order to gain easier access to their common food sources.