Scientists say they’ve found artifacts in Idaho that indicate people were living there around 16,000 years ago, providing new evidence that the first Americans arrived here by following the Pacific Coast.
Other experts were split on how old the artifacts were and what they signify — not an unusual reaction in the contentious academic community studying early humans in the New World.
In the oldest part of the Cooper’s Ferry site in western Idaho, Davis and his colleagues found 43 flakes that had evidently been chipped off of stones in the process of making tools like those found in younger areas of the site. They also found four such flakes that had been modified to be used for a task like cutting or scraping, as well as pieces of bone that indicate discarded food, Davis said.
The site is between 15,280 and 16,560 years old and was occupied repeatedly over time, according to the team’s report in Friday’s edition of the journal Science.
What does it all mean? For one thing, the researchers said, its age supports one side of a debate about just how the first Americans arrived.
The traditional narrative is that the peopling of the Americas began after a migration across a now-submerged land bridge called Beringia that used to extend from Siberia to Alaska. The migration’s progress south from there was blocked for a while by massive ice sheets in Canada, but eventually a gap in the ice opened and people moved through this so-called “ice-free corridor.”
But in recent years, as scientists have found earlier and earlier signs of humans living in the Americas, some have argued that people showed up before that corridor appeared. Perhaps they traveled the Pacific instead, either on foot or by boat — or both.
Davis said the new work indicates people were living in Idaho long before the corridor opened, citing other research that says it was open by about 14,800 years ago. The best explanation, Davis said, is that “they came down the coast and took a left-hand turn south of the ice, and went up the Columbia River Basin.”
The site also revealed a style of stone projectile point that resembles artifacts of similar age on the Japanese island of Hokkaido. That supports the idea that the migration that led to the first Americans may have begun in that area, when Hokkaido was part of a larger land mass, Davis said. Or it could have started somewhere else in northeast Asia, but still reflect a cultural contribution of the Hokkaido area, he said.
A migration from Hokkaido could have skirted the southern coast of Beringia before heading south along the Pacific, he said.
Experts who weren’t involved with the study but were familiar with the work gave differing opinions on the site’s age, reflecting the difficulty of interpreting data for assigning ages to artifacts. A site in Texas has also been dated to about 16,000 years, but Davis said the technique used for Cooper’s Ferry is more precise.
Dennis Jenkins, senior research archaeologist at the University of Oregon’s Museum of Natural and Cultural History, said the Idaho site appears to go back 16,000 years. He also said the paper provides “a major advance” by linking early Americans to Japan more firmly than before.
Michael Waters, an archaeologist at the Center for the Study of the First Americans at Texas A&M, called the site “a great discovery.”
Waters said he prefers an age of between 14,200 years and 15,000 years ago. That would put it in the time frame of several sites in Texas, Wisconsin and Oregon, he said. As for the Japan connection, he said: “I think they’re on to something there.”
But archaeologist Ben Potter of the University of Alaska in Fairbanks questioned the reported age of the artifacts. He said the most secure age estimates do not precede the opening of the ice-free corridor, so the new paper doesn’t rule out that possible entry point. He also said he was not convinced by the comparison with the Japanese artifacts.