Cockroaches are mostly nocturnal insect, with biting mouthparts and legs that are adapted for swift running. The body is oval and dorsoventrally flattened, allowing the animals to hide in narrow spaces, for example under bark or in crevices of trees and rocks. The head is usually hidden beneath the pronotal shield, and there is a pair of short cerci at the end of the abdomen.  In winged species, the forewings (tegmina) are leathery and protect the delicate hindwings.   

Most cockroaches are scavengers, with fairly broad diets, but a few species in the family Cryptocercidae specialize on dead and decaying wood.  Some cockroaches invade human dwellings and are significant household pests.