The foraging ancestors of the Ancient Ones were nomads. For food they killed small animals, using spear and atlatl. They also harvested wild plants.
The historical line between the hunter-gatherer culture and the emerging Ancestral Puebloan culture is defined in part by evidence that around 1200 B.C. they began to settle down in one place for longer periods of time and domesticate and cultivate crops from one year to the next.
In the Basketmaker period the primary crop was corn, also known as maize, which is believed to have evolved from teosinte, a wild grass native to what is now Mexico and Central America. Because the climate in the Southwest was (and is) much colder and drier than that of Mexico, Ancestral Puebloan farmers probably cross-bred different corn varieties and selected those that survived best. At the same time, they were growing squash, which also came from Mexico. Around A.D. 500, beans were added to the Ancient Ones diet. Pottery, which was supplanting baskets for food storage and cooking, was essential to the beneficial use of this new dietary item because of the bean’s longer cooking time.
The Cliff Dwellers often sun dried their vegetables. Many food items were stone-ground, using grinding stones — metate and mano. Seeds were parched in hot coals and ground into meal. Pine nuts were ground into a paste. Corn was ground to make corn meal. Food was stored in large pits, often sealed in baskets or pottery for protection from insects, animals and moisture.
Unlike the Hohokam people to the south, the Ancestral Puebloans did not build huge irrigation canals. Their diversion and collection of natural precipitation was not irrigation in the usual sense. In general, their dry-land farming relied on the natural blessings of rain and the runoff from melting snow. Often they helped Mother Nature by building check dams, terracing hillsides or locating fields near the mouths of arroyos and springs. One of the largest of their water conservation efforts was a 500,000 gallon reservoir at Mesa Verde.
For all of their reliance on domestic crops, the Ancient Ones did not abandon the foods of their nomadic forebears. Even in A.D. 1300, corn, squash and beans, alone, would not sustain them. They still hunted animals like deer, rabbits and prairie dogs. And they gathered wild plants for sustenance. The nuts of the piñon pine were eaten roasted or ground. They ate the ripe fruit of the banana yucca and dried the red fruit from the prickly pear cactus for later consumption. Pigweed and amaranth provided greens.