How the door opened: the peopling of the New World.

The timing, pathways, and number of migrations involved in the early peopling of the New World are examined from a variety of perspectives. Ultimately, the occupation of the Western Hemisphere was a direct result of boreal cultural adaptations in the Old World. Here, we discuss (1) the dates of appearance of these boreal cultural adaptations and their relevance to the peopling of America, (2) archeological and linguistic evidence bearing on the earliest peopling of the New World, (3) ecological and linguistic evidence on two alternative routes into the New World, and (4) the assumptions present in various migration models. The relative strengths of opposing hypotheses are analyzed by observing whether different approaches point to the same answers.