Land Bridge to the New World

Prehistory

Between roughly 80 000 and 12 000 years ago, a massive glacier covered much of what is now Canada and the United States. An expanse of land then connecting Alaska and Siberia was eventually covered by water as the great icecap melted, and Bering Strait grew to separate North America from the Asian continent.

The first to cross this land bridge were ancestors of the Paleo-Indian peoples -- big-game hunters following their prey. It is thought that upon their arrival to the North American continent, these hunters continued through a corridor of land that had been left exposed between two sections of the icecap. When exactly -- between 20 000 and 12 000 years ago -- this migration occurred is much debated among specialists.

While the land-bridge theory is almost universally accepted, some believe that the first travellers to North America may have come by water. There is presently no solid evidence to support this.