According to popular theory the first inhabitants of north America arrived during the last Ice Age. Between 15,000 and 40,000 years ago people are believed to have crossed from Asia to North America on a natural land bridge, where the Aleutian Island chain now exists.
These people migrated south, hunting mastadons and mammoths, giant ground sloths, camels and long-horned bisons. They ate the meat and used the hide for clothing and shelter. Their weapons consisted of rocks and obsidian-tipped spears. In time the atlatl, a device used to throw spears or darts, was developed. It was not until about 3,000 years ago that the bow and arrow was introduced to North America.
On the eve of the white man's arrival the population of North America, divided among 500 tribes, was estimated to exceed one million. But the Europeans brought with them diseases from which the native people had no natural immunity and plagues of smallpox, fever, tuberculosis, measles and venereal disease swept through the Indian nations with devastating results. Ninety percent of the people died: entire tribes were wiped off the face of the earth. Those who remained were rounded up and placed on reservations. The way of life they had known for countless centuries was doomed.