The progress of the early human migration from Asia into the Americas was incredibly slow. In fact, the people whose descendants ended up populating the American continents may have spent as many as 10,000 years inhabiting the Bering Land bridge. 

Around 3.5 million years ago, our primate ancestors made a shift in their diet that some scientists believe set them on course for human evolution. The findings were reported in a series of studies published this week in the Proceedings for the National Academy of Sciences.