These are excerpts, see here for more information and read Red Earth, White Lies by Vine Deloria for the complete story and evidence.
I will offer here a very condensed explanation of the facts that clearly demonstrate that the 'Bering Strait Theory' has never graduated beyond being a theory. Before I begin, however, I would offer that no one has ever exposed the foolishness of this myth with more research, intelligence, and eloquence than my fellow Oglala Lakota, Vine Deloria Jr., Phd. in his best-selling book, 'Red Earth, White Lies'. Read his chapter on the Bering Strait in this book and I assure you, you will never look at this 'theory' the same way ever again.
The Bering Strait Myth is not so much science as it is politics. Much objective modern science in the past several decades has even suggested that it is highly questionable if there ever was a so-called 'ice-bridge'. Yes, that's right, from an in-depth, intensive and non-politically affected scientific study of earth history, countless scientists (mostly non-American) have concluded that there most likely never was an 'ice-bridge'! When I was young, it was '12,000 years ago' when Indians supposedly migrated over the 'ice-bridge' into this continent. Over the years, I have watched this number go up from 12,000 years, to 20,000 years, and now in recent print, I have begun to see the number placed at 30,000 years! It seems that scientists just move the number back whenever something Indian is discovered that pre-dates their Bering Strait migration figure! I can tell you this, science does not have the market cornered on fact, nor on truth.
Most U.S. History books, and many other books written about North American Indigenous people, begin by propagating the Bering Strait Myth, telling the silly story of thousands, even millions, of early First Nations people migrating from Asia, crossing the so-called 'ice-bridge' of the Bering Strait. You may be surprised to discover that the scientists who support the Bering Strait Myth also want us to believe that many kinds of animals, plants, and even trees crossed over the Bering Strait into this Turtle continent. No kidding! Let me give you some more hard facts to help you discard, at long last, the foolish Bering Strait Myth once and for all.
First - Many Indigenous Nations have calendars that have been counting the years for a very long time. I am aware that the calendar of the Mohawk Indian Nation has been counting the winters for over 33,120 years. This pre-dates the so-called 'ice-bridge' of the Bering Strait theory, unless, of course, the Bering Strait scientists decide to move the interestingly illusive time period of our early migration back to 40,000 years! Many American Indian early histories tell of events that took place on this Turtle continent (North America) long before any so-called ice age. But, for political reasons, our histories have been mostly ignored. You see, the Bering Strait, in truth, is a theory that was born of the politics and propaganda of early America. In the midst of the American 'Manifest Destiny' social climate, the Bering Strait theory provided a 'scientific' means to justify the taking of ancestral Indian lands. In short, the mythical theory eased the conscience, as it was a way for land hungry immigrants to believe that, because Indian people were only 'recent inhabitants' of this land that it was not our 'homeland'. Therefore we were, in their minds, not any more the 'original people' in this land than they were. This was, and still is, the political power of the infamous 'Bering Strait theory'.
The Bering Strait theory would have us believe that all of North America was uninhabited by human beings of any kind until the supposed 'ice age'. The theory contends that the ancestors of American Indians originated in Siberia. Factual history of the ancient people of Siberia in those times indicates that these people had plenty to eat, were very settled into their communities, and the land they lived on. The Bering Strait theory wants us to believe that countless thousands of people from these well established communities in Siberia, despite the fact that they had everything they needed, just left everything behind to head north into a frozen tundra to 'chase and hunt game' (which, by the way, also decided for some crazy reason to leave their rich marshlands and head for the ice). Not only does it not make any logical sense, it doesn't make any historical, cultural or scientific sense! The culture of those ancient Siberian people is as different from North American Indigenous cultures as a shark is from an eagle! There are no cultural links between ancient Siberian peoples and the Native peoples of this continent to indicate any human descendancy connection. It simply makes no sense.
Then there is the 'ice bridge' itself… In order to create the Bering Strait 'bridge', we first need the timeless normal function of the earth's wind, evaporation and precipitation patterns to all of a sudden, just change completely. The wind streams need to begin to travel south to north, instead of west to east. In order to create the Bering Strait 'bridge', we need to drop the water level at least 200 ft. So an enormous amount of water needs to be evaporated - about 20.82 million cubic kilometers, enough water to cover an area of 5 million square miles with a sheet of ice 1.2 miles thick. To complete the process, we need this massive evaporation to take place in the warmer climates of the south, then the moisture laden clouds need to break the natural laws of the planet and head to the far north so they can then 'dump' their precipitation as ice over the area of the Bering Strait. To quote from Professor Vine Deloria Jr., "We cannot today conceive of a natural process that would evaporate this amount of water and transport it safely from the temperate zones to ensure that it precipitated as ice in Canada." As you can see, when you begin to explore the facts, it becomes more and more clear how ridiculous the Bering Strait theory really is. The Native people of this Turtle continent did not 'migrate' to this land… we have always been here…
You may notice that I keep italicizing the word theory. My reason for doing this is that I think it is very important to note that this myth is still identified today as a theory, not a fact. A theory is defined as: "an offered opinion which may not positively be true." Yet this theory is taught in schools still today as if it were the gospel truth. It is far from truth, and the time for it to be removed from lessons about American Indian people is long overdue.
I do encourage teachers to use this document in all classrooms where it has been decided to teach the truth of Indian culture. And again, I strongly suggest you get the book by Vine Deloria Jr., Red Earth, White Lies. May you be blessed on your journey to truth.