Based upon evidence found in anthropological studies and archeological research, it is believed that all Native Americans are descended from people that made a migration from Siberia over the Bering Strait and into the Americas. This is a generally accepted theory, although holes and controversies still exist as to the exact means of travel these Native American migrations took. The basic idea is that at the end of the last ice age, a land bridge was revealed, and then used, as nomadic people followed the animals they hunted for food and clothing. It has been suggested that this could have occurred far earlier in history, if the people had used the coasts to avoid the ice of the interior.
The timeline associated with this migration is between 17,000 and 11,000 years ago, but this presents a problem with the evidence that humans had been living in South America before said time period. Many of the Native American tribes and nations shared the same spoken histories and stories, or at least very similar ones. In addition, many speak the same language, even though their geographic locations are hundreds and even thousands of miles apart, implying they all shared a common ancestry. It is possible that the migration took place in the previous ice age after an influx of oceanic people came to Siberia, who then migrated across a land bridge.
It has been concluded that several waves of migration took place, and each could be responsible for differing cultures based upon the animals that the nations followed. The first set of migratory people would have included the basis of the Clovis and Folsom cultures that followed the bison. The second wave would have been comprised of the Na-Dene peoples of whom the Navajos, Apache and Dene are descended from. This information is based upon recent genetic studies that show four distinctive migrations to the Americas via Siberia over land or by sea. The Inuit and Aleut people may in fact have been the last to cross, and probably this event happened by sea, after the land bridge disappeared.