Pithouses were very common structures in the American Southwest during the early and middle periods of the Anasazi, Mogollon and Hohokam cultures, and were also found in cultures extending north and west of the Colorado plateau. The emergence of the pithouse marks the transition between a nomadic hunting-and-gathering livelihood and a settled agricultural way of life which also relied on wild plants and animals for food. Pithouse structures were probably the forerunners of the kivas built later in the Pueblo periods, and share many characteristics with them.