People chose the coast during the big chill

[wnylib]

1. This might help to explain

something I noticed long ago when maps of Homo sapiens mtDNA haplogroups out of Africa were published. Some of the older groups from which later, descendant groups developed, seemed to follow coastlines along Africa, the Arabian peninsula, India, and on into eastern Asia.

If people were finding richer sources of food along coastlines during the glacial maximum, it seems natural that they would follow coastlines. Harsher conditions inland, due to droughts when so much water was tied up in glaciers, would act as a catalyst for early humans to get on the move to find and follow food sources.