For decades, students were taught that the first people in the Americas were a group called the Clovis who walked over the Bering land bridge about 13,500 years ago.
Now scholars are supporting the "kelp highway hypothesis," which holds that people reached the Americas when glaciers withdrew from the coasts of the Pacific Northwest 17,000 years ago, creating "a possible dispersal corridor rich in aquatic and terrestrial resources." Humans were able to boat and hike into the Americas along the coast due to the food-rich ecosystem provided by coastal kelp forests, which attracted fish, crustaceans, and more.
[T]he big question now is when pre-Clovis people actually arrived in the Americas. They suggest the arrival could be as early as 20,000 years ago on the verdant kelp highway. Other researchers, however, say people could have arrived during a temperate period about 130,000 years ago. A recent paper in Nature describes what appear to be the 130,000-year-old butchered remains of mastodons in California, along with sharp stones used to deflesh the animals. There is plenty of skepticism in the scientific community about this discovery, but the evidence can't be ignored.
[The original study can be found here]
The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion, and analysis. Read full, original post: Most scientists now reject the idea that the first Americans came by land