Evidence suggests big-game hunter gatherers crossed the Bering Strait from Asia (Eurasia) into North America over a land bridge (Beringia), that existed between 47,000–14,000 years ago. Around 18,500-15,500 years ago, these hunter-gatherers are believed to have followed herds of now-extinct Pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran ice sheets. Another route proposed is that, either on foot or using <answer>primitive boats</answer>, they migrated down the Pacific coast to South America.
What other way could they have crossed on to this continent?
primitive boats