Known as "Clovis First," the predominant hypothesis among archaeologists in the latter half of the 20th century had been that the people associated with the Clovis culture were the first inhabitants of the Americas. The primary support for this was that no solid evidence of pre-Clovis human inhabitation had been found.
"I think we are on the edge of a paradigm shift now," says [Michael Waters of Texas A&M University in College Station]. "We're past the Clovis-first model. We have robust evidence of people here before Clovis that is in a secure geological context and well-dated. Now we can seriously sit down and develop a new model for the peopling of the Americas." [Douglas Bamforth of the University of Colorado at Boulder] echoed his opinions. "It might be time to stop talking about Clovis-first altogether."
One favoured theory, known as "Clovis first", says that during the last Ice Age, people from Asia followed herd animals across a land bridge connecting Siberia to Alaska and established the first settlements in North America. The Clovis culture is characterised by pointed stone tools. But recent finds of artefacts that pre-date the Clovis...have challenged the Clovis-first hypothesis.
The radiocarbon dating of the Western Stemmed projectiles to potentially pre-Clovis times, [Dennis L. Jenkins of the University of Oregon's Museum of Natural and Cultural History] said, provides new information in the decades-old debate that the two point-production technologies overlapped in time and may have developed separately. It suggests that Clovis may have arisen in the Southeastern United States and moved west, while the Western Stemmed tradition began, perhaps earlier, in the West and moved east.
Archaeological work in Oregon's Paisley Caves has found evidence that Western Stemmed projectile points -- darts or thrusting spearheads -- were present at least 13,200 calendar years ago during or before the Clovis culture in western North America. In a paper in the July 13 issue of Science, researchers from 13 institutions lay out their findings, which also include substantial new documentation, including "blind-test analysis" by independent labs, that confirms the human DNA pulled earlier from human coprolites (dried feces) and reported in Science dates to the same time period.
The Clovis-First model, however, requires all American sites older than Clovis to be rejected, and this appears to be no longer possible. The Clovis-First model does not explain the apparent synchroneity between Clovis and the early Paleo-Indian sites of South America. Finally, a late-entry and rapid dispersal of humans across the New World is inconsistent with the distribution of genetic variation observed in Native American populations today.
Until recently, it was generally believed that about 13.5 thousand years ago the first migrants spread rapidly from Beringia to Tierra del Fuego in a few centuries, passing through an interior ice-free corridor in western Canada, becoming Clovis, and hunting to extinction the last of the New World’s megamammals. Today, we realize that the peopling of the Americas was a much more complex process, because of two significant developments during the past decade. Molecular geneticists, using refined methods and an ever-increasing sample of living populations and ancient remains, are now capable of providing reliable information on the Old World origins of the first Americans, the timing of their initial migration to the New World, and the number of major dispersal events.
Dennis Stanford of the Smithsonian Institution spent years in Alaska and found no connection between Siberian artifacts and Clovis technology. His new theory is that Clovis people came not from Siberia, but from Europe. The Solutrean people of France and Spain were their predecessors, he says.
For years it was believed that Clovis people came through Alaska using a land bridge from Siberia, then traveled south just as ice sheets across Canada were breaking up. So archeologists have long looked for signs of Clovis people in Alaska.
The earliest reliably dated evidence of human habitation in North America are 11,500-year-old fluted projectile points found in Clovis, New Mexico. The distinctive points, which could be attached to a wooden spear to make a formidable weapon, became identified with small groups of people spreading slowly across North America who came to be known as the "Clovis" culture. One of the first pieces of evidence to call the interior route—the so-called "Clovis first" theory—into question was confirmation in 1997 of human habitation at a site known as Monte Verde in southern Chile.
The popular Clovis-first model (named for the New Mexico town where artifacts of a certain type were first found) holds that humans arrived in North America via the Bering land bridge that once connected Alaska to Asia. They then walked southward through an ice-free corridor during a period of glacial retreat. For a long time, that model was king, ensconced in countless high school textbooks.