A PEDESTRIAN HYPOTHESIS
“Walking on two feet is a defining human characteristic, and two feet carried our progenitors out of Africa to people the planet. Archeologists have long thought that people originally came to the New World as pedestrians, too. . .
[But] “What if they used their heads instead of their feet? What if they came by boat?”
That’s from a feature article I wrote in 1999. Prescient and a trend-spotter, if I do say so myself. Because–
Anathema in 1999, this outrageous idea, that the First Americans were boat people, has more or less supplanted the former conventional archaeological/anthropological wisdom in less than a couple of decades. The now-defunct story is the one you grew up with: that about 13,500 years ago, the First Americans walked from Asia to Alaska. They came across a temporary land bridge spanning the Bering Strait. Beringia existed at that moment only because the Ice Age had locked up so much ocean water. It has long since vanished beneath the melted seas.
These hardy hunters, whose tool kit included distinctive and beautifully made stone spear points, were then pictured striding south down an ice-free corridor in Western Canada. Some of them pushed on, getting eventually to the southern tip of South America.
But some settled in the US, including a settlement near the present-day town of Clovis in New Mexico. That’s where archaeologists first found those special spear points, a 1930s discovery that generated the tale that it was these people, who came to be called Clovis Man, who were the First Americans.
Clovis points have been found at several American sites: in much of the US, especially the East, but also in Mexico, Central America, and even northern South America. Furthermore, genetic evidence suggests that most of today’s Native Americans are descended directly from the Clovis people.
Clovis Man got around.
But now we know Clovis Man wasn’t the first. The boat people version begins earlier, more than 16,000 years ago, maybe as long as 20,000 years ago, with Asians crossing to North America by boat. (We know that Native Americans’ ancestors were Asians because genomics.)
They wouldn’t have come directly across the ocean, although humanity had splendid navigation skills by then. Instead they hugged the shoreline. There they found plenty of fish, shellfish, and other unfrozen resources even when the rest of the land was glaciated. They headed south along the West Coast, arriving eventually in southern Chile–close to the tip of South America–before 14,500 years ago. That’s the date of the Monte Verde site.
The death of the Clovis First story was marked officially in a November 3 Science paper (paywalled, sorry) written by several specialist archaeologists. They announced: “In a dramatic intellectual turnabout, most archaeologists and other scholars now believe that the earliest Americans followed Pacific Rim shorelines from northeast Asia to Beringia and the Americas.”
They call that Pacific Rim shoreline the kelp highway. Annalee Newitz explains at Ars Technica: “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.”
The Science paper has a nice map of early human sites in Asia and the Americas. I’m reproducing it here in tiny form but if you click on the map below, it should be made larger (and readable) in a different window. You can also find the Americas-only part of this map accompanying Erin Ross’s post at Axios, and the full map at Newitz’s post.
This map is pretty mind-blowing. Not only are there pre-Clovis sites along the Americas’ west coasts, there’s one in Florida. (Details of this find in Gemma Tarlach’s post at Dead Things.) Assuming the Florida date of 14,500 years BP holds up–and the fact that it’s on this semi-official map at all makes the date plausible–that means people had gotten all the way to the East Coast by then.
From Asia. We’re not talking here about the discredited Solutrean hypothesis, which argues that there was early American settlement by Ice-Age Europeans. The genetic evidence from the Clovis people seems to have dealt a final blow to that notion, as Dienekes observed in 2014: “It is remarkable that a single ancient DNA sample can sweep away much of the nonsense that has been written on the topic in the past.”
(The claim that humans were in Southern California 130,000 years ago, which I wrote about here at On Science Blogs last May, remains highly unlikely. Or, as one of the Kelp Forest authors politely told Jen Viegas at Seeker, “evidence for earlier migrations is problematic and speculative.”)
The evidence for Boat People First comes from only a few coastal archeological sites that are persuasively dated to before the Clovis people arrived here. But the Boat People had no distinctive cultural detritus marking their presence–no specific tools like Clovis points, which are all over the place. Just like Clovis genes.
The Kelp Highway authors do not regard the paucity of early sites as a weakness in the Boat People First idea. There’s a good climatological explanation. Shorelines are very different today, so Boat People sites would have drowned, as Beringia did.
The scientists draw philosophically on one of our favorite science aphorisms: Absence of Evidence is not Evidence of Absence. What is needed, they say, is underwater archeology that looks for living sites that vanished under glacier melt thousands of years ago. Searches for these will be possible because of new technologies Newitz mentions, such as ocean-going drones and underwater lasers.
Figuring out the earliest settlement(s) of the Americas is a fascinating topic, no question. In addition to the Boat People, there’s scattered evidence of other groups of early explorers of the Americas. Some of this evidence is genetic too, as I wrote about here.
But I can’t help wondering if these studies are mainly of historical (or prehistorical) interest. If most Native Americans are descended from Clovis Man rather than the Boat People or other early settlers, how much does it matter who, technically, was the First American? In the genetic sense, it’s still Clovis First.
Source: PLOS EveryONE