For a long time archaeologists have assumed that all non-European people who came to the Americas were from Asia. They thought these people came through Alaska. Recent discoveries and new information may show that there were several different migrations. People might have come across both the Atlantic and Pacific oceans. The early migrations took place by 12,000 to 15,000 years ago. Some may have occurred before 20,000 years ago. The earliest people in the are called Paleo-Indians. It is generally thought that Paleo-Indians arrived in the American Southwest between 12,000 and 13,000 B.C.

Two important archaeological sites from this time are the Clovis and Folsom sites. They are in New Mexico. The Clovis people date to the Pleistocene era during the last Ice Age. Many large animals roamed North America in those days. These animals, called Pleistocene Megafuana, included mammoths, a large variety of bison horses, camels, and some animals such as the giant tapir. These animals became extinct. (The modern horse was later introduced into North America by the Spanish.)

Paleo-Indians mainly hunted large animals for food. The Clovis people hunted to supplement their diets. Most Clovis sites are large animal kill sites, rather than campsites. They also ate small game and plants, but there is little evidence of gathering plants or other parts of their life style. The Clovis people made distinctive projectile points with long, thin, stone blades with a flute or channel removed from the base.

These people lived in small, mobile groups, probably one or two families. They probably made portable shelters from available materials. They would use caves when they could. It is not known what clothing they had. Archaeologists have found fine bone needles. These needles indicate that they used skins and leather. Things such as elk teeth may have been used for decoration. Most of their tools were made of stone. Some were made from bone. Art was expressed in stone. Many archaeologists consider the stone points to be among the most beautiful ever made. Art may have been used as hunting magic.

Paleo-Indians probably ranged widely with few limits. Possibly, there were different groups in the mountains and on the plains. Usually they traveled in small family groups. They probably joined other family groups to hunt game.

About 9000 B.C., the Folsom people appeared in the southwest. By that time, the mammoth and other Pleistocene megafauna had become extinct. The Folsom people hunted a large bison, bison antiquus, that later became extinct, as well as more familiar animals, such as pronghorn (antelope) and jackrabbit. The Folsom people made some of the most elaborate projectile points known.

The Archaic period was a major turning pint. In the late Archaic period, people in the Southwest first used plants that had once been wild. The Archaic period followed the Paleo-Indian period. It dates from about 5500 A.D. to about A.D. 1. There is some uncertainty as to when the Archaic Period ends.

The Archaic people were hunters and gatherers as the Paleo-Indian people had been. The Pleistocene megafauna had long been extinct. These people hunted smaller game such as deer and rabbits. They began relying on collecting wild plants. Eventually they used domesticated plants-- plants that had once been wild.

There were changes in the environment during this period. There was less rainfall. During the early Archaic (5500-3000 B.C.) conditions may have been very hot and dry compared to the wetter and cooler climate of the Paleo-Indian.. In the Late Archaic (3000 B.C.-A.D. 1) it may have been slightly wetter than the early Archaic.

The places where evidence of the Archaic people have been found are usually places where they could find a variety of food. These sites are often found at the heads of canyons where there is usually water. They are also found on the canyon bottom. These people used the plants and hunted the animals found on the canyon rim and floor. Archaic sites are frequently found covered by sand dunes that have a large variety of plants covering them.

During the Late Archaic period, maize was introduced from Mexico. They probably grew squash about the same time. Beans were cultivated sometime later. This change -- cultivating crops -- marks a significant change in the cultural development in the American Southwest.

People tended to live in more permanent settlements by the end of the Archaic period. From that time (about A.D. 1) the beginnings of distinct cultures appeared. The Ancestral Puebloans (Anasazi) appeared on the Colorado Plateau. In the southern deserts, a people now called Hohokom developed, and a group now called Mogollon appeared in the mountains between these other peoples.