Colubridae, the colubrid family.
Southwestern North America, primarily the Californias and Arizona.
A wide variety of habitats from desert to pine forest.
They are famous for killing rattlesnakes, although these are not their preferred prey, and are immune to rattlesnake venom. However, rattlesnake fangs can cause wounds which are sometimes fatal. When confronted by a kingsnake, a rattlesnake backs away, recognizing the kingsnake as a predator by scent. Rather than strike, the rattlesnake usually tries to protect his head, which the kingsnake tries to grab and may begin swallowing while wrapping itself around the rattlesnake, constricting.
These snakes have black or brown bands around their bodies, alternating with white or yellow. In the Colorado Desert, they are black & white, while in other areas they are brown and yellow. Striped ones sometimes occur along with banded ones in the same clutch in San Diego County.
They are nocturnal and crepuscular predators in the desert, feeding on lizards, frogs, birds and their eggs, small mammals and other snakes, seizing prey with teeth, then killing by constriction.
They are taken by owls, coyotes, roadrunners and red-tailed hawks, as well as other kingsnakes and may strike, hiss and vibrate their tails to imitate a rattlesnake, or emit a foul odor as defense.
The mating season is during spring or early summer, when females deposit 4-12 eggs in damp sand under a rock or other covering. The hatchlings emerge about 10″ long.