ABSTRACT
The migrations of early humans are traced from their origins in Africa to the threshold of America in the far-off reaches of northeastern Siberia. Ancestors of the first Americans entered western Beringia by 21,000 bce. At that time, a broad isthmus joined Alaska and Siberia, which today is largely submerged. Early Eurasian bands of hunters and foragers (?) adapted to cold Pleistocene conditions, eventually spread northeastward far enough to enter North America. Lines of evidence from biology (genetics, osteology), linguistics, and archaeology are mutually consistent. The earliest bands to reach the southern margins of the vast sheets of glacial ice were probably accompanied by dogs. The last gasp of the Pleistocene, known as the Younger Dryas climatic episode, provided the environmental context for the spread of humans across an American landscape that had never before been home to our species.
