The heart of that territory has long since been submerged by the Pacific Ocean, forming the present-day Bering Strait.
But some 25, to 15, years ago, the strait itself and a continent-size expanse flanking it were high and dry. Much of this new theorizing is driven not by archaeologists wielding shovels but by evolutionary geneticists taking DNA samples from some of the oldest human remains in the Americas, and from even older ones in Asia.
Those discoveries have opened a wide gap between what the genetics seem to be saying and what the archaeology actually shows. Humans may have been on both sides of the Bering Land Bridge some 20, years ago. But skeptical archaeologists say they will not believe in this grand idea until they hold the relevant artifacts in their hands, pointing out that no confirmed North American archaeological sites older than 15, to 16, years currently exist.
But other archaeologists are confident it is only a matter of time until older sites are discovered in the sprawling, sparsely populated lands of eastern Siberia, Alaska and northwestern Canada. Yet no matter when or how they made the trek, the coast of what is now Canada was on their itinerary. The rugged shoreline of British Columbia is carved by countless coves and inlets and dotted with tens of thousands of islands.
On a cool August morning, I arrived on Quadra Island, about miles northwest of Vancouver, to join a group of researchers from the University of Victoria and the nonprofit Hakai Institute. The site was located on a tranquil cove whose shores were thick with hemlock and cedar. When I arrived, the team was just finishing several days of digging, the latest in a series of excavations along the British Columbia coast that had unearthed artifacts from as far back as 14, years ago—among the oldest in North America.
On a cobble beach and in a nearby forest pit that was about six feet deep and four feet square, Fedje and his colleagues had discovered more than 1, artifacts, mostly stone flakes, a few as old as 12, years. All testified to a rich maritime-adapted culture: rock scrapers, spear points, simple flake knives, gravers and goose egg-size stones used as hammers.
Fedje reckoned that the cove site was most likely a base camp that was ideally situated to exploit the fish, waterfowl, shellfish and marine mammals from the frigid sea. For Mackie, the archaeological riches of the British Columbian coast reveal a key flaw in the original Bering Land Bridge theory: its bias toward an inland, rather than a marine, route. These were the same people as us, with the same brains. And we know that in Japan people routinely moved back and forth from the mainland to the outer islands by boat as long ago as 30, to 35, years.
Several recent studies show that as the last ice age began to loosen its grip, portions of the coastline of British Columbia and Southeastern Alaska were becoming ice-free as far back as 17, to 18, years ago. Fedje and others note that humans walking across the Bering Land Bridge from Asia could have traveled by boat down these shorelines after the ice retreated.
Today, the coast of the Pacific Northwest bears little resemblance to the world the first Americans would have encountered. The lushly forested shoreline I saw would have been bare rock following the retreat of the ice sheets. And in the last 15, to 20, years, sea levels have risen some feet. But Fedje and his colleagues have developed elaborate techniques to find ancient shorelines that were not drowned by rising seas. Before invoking humans, however, the researchers need to better rule out the possibility that natural forces broke the rocks and bones, says David Meltzer, an archaeologist at Southern Methodist University in Dallas, Texas.
McNabb would like to see the breakage patterns analysed in more detail. But after revisions that elaborated on the dating work and demonstrated that hitting modern elephant bones with large rocks produces damage patterns similar to those seen on the mastodon bones, she is now convinced that hominins created the California site.
If humans or their ancient relatives were responsible, there are several candidates. They point to ,year-old Homo sapiens -like teeth from China and to hints that some indigenous groups in South America carry trace ancestry from a possible earlier migration into the Americas.
Chris Stringer, a palaeoanthropologist at the Natural History Museum in London, favours Denisovans or Neanderthals, which both lived in southern Siberia at least , years ago. Yet there is no evidence that either group could survive the epic Arctic voyage across from Siberia to Alaska. Steven Holen hopes that other scientists will join the search. Holen, S. Nature , — Skoglund, P. Article Google Scholar.
Download references. You can also search for this author in PubMed Google Scholar. Fishing for the first Americans Sep Ancient migration: Coming to America May The first Americans: Clues to an ancient migration.
Reporter Shamini Bundell investigates how a new fossil find may rewrite the history of human migration. The results suggest the remains are , years old, give or take 10, years. The current consensus view is that humans first reached the Americas much more recently, perhaps just 15, years ago. Exactly who those people were is impossible to say as there were no human fossils at the Californian site. Both of these groups were probably present in Siberia more than , years ago.
Holen says sea levels were low and a land bridge existed between Siberia and North America just before , years ago. Either group could in theory have wandered across. Alternatively, it might have been modern humans — Homo sapiens — that made it to the New World , years ago, says Fullagar. Recent archaeological evidence suggests our species was in China , years ago , which is far earlier than once thought. Perhaps modern humans were in East Asia even earlier than the Chinese fossils suggest, and moved into the Americas from there.
They have found almost stone tools buried in sediments in the cave, including blades, points and scrapers. No human remains or DNA have been found. The youngest samples of sediment are at least 12, years old, and the oldest may be 33, years old Nature , DOI: This suggests that people lived in the Americas before a crucial event: the last glacial maximum — the peak of the last glaciation. Between 26, and 19, years ago, ice sheets extended across much of North America.
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