Adults are uniformly black or bluish black both above and below, with the chin, throat, and lips usually tinged with reddish or orange pigmentation. The young are lighter in color and have a faint banded pattern. Indigos lay from five to twelve white eggs in May or June. Hatching occurs in August and September. The young indigos may approach 2 feet long when they hatch.
Indigo snakes feed on small mammals, frogs, toads and other snakes.
They feed especially heavily on frogs and snakes. They can eat rattlesnakes and other pit vipers as well as coral snakes, because they are immune to their venom. The indigo snakes large size and strong jaws enable it to eat its prey live. It uses its large body to hold its prey, but does not kill by strangling like snakes which are constrictors. Its victims die from suffocation, as they are eaten head first.