The first explanation is: they hopped over there. No, not in one big hop! Rather, the land was dry and they migrated over on land bridges. This is a very reasonable and probable explanation but in order to understand it we must understand the effects of the ice age and plate tectonics. Previously, I presented the case for an ice age occurring after Noah's Flood. Such an ice age would have turned much of the water into ice and thus lowering the sea level and allowing a dry land passage. Also, the effects of plate tectonics could have formed these land bridges.