The Peopling of the Americas: Evidence for Multiple Models

By Gemma Tarlach | August 8, 2018 1:00 pm



A new review of evidence for the peopling of the Americas suggests multiple routes, including coastal and overland, such as through this Alaskan landscape, were likely. (Credit: Ben A. Potter)

A new review of evidence for the peopling of the Americas suggests both coastal and interior routes, such as through this Alaskan landscape, were possible. (Credit: Ben A. Potter)

Exactly how and when the peopling of the Americas took place has long been one of the hottest debates in science. For every new paper that emerges with evidence of an interior or coastal route, it seems another team publishes contradictory conclusions. Authors of a new review of archaeological, geological and paleogenetic research have concluded that both of the two main models are reasonable — and that a couple fringe theories are most definitely not.

If you’re a regular reader of Dead Things, you’re familiar with the ongoing kerfuffle between advocates of the two leading theories about how humans arrived in the Americas, but let’s do a quick recap.

Advocates of the interior route believe people from northeastern Siberia traveled on foot, likely following large herds of game animals, eastward over the land bridge of Beringia into what’s now Alaska. Beringia, by the way, has been exposed multiple times over the past several million years, during various ice ages when sea levels dropped. It’s sometime during the end of the last Ice Age that humans began their move from Siberia into Beringia and eventually Alaska. The interior route has been the dominant model for decades.

Then we’ve got the coastal route, often called the Kelp Highway model, which has gained traction particularly in the last couple years. It suggests people from northeastern Siberia followed the coast by boat, including along sea ice at times, around the northern Pacific and all the way to the Americas, continuing down the coast potentially as far as modern-day Chile. The resource-rich waters, full of fish, shellfish, seals and kelp, plus birds overhead, would have sustained the explorers.

Both models agree on some crucial points, particularly that individuals from northeastern Siberia traveled eastward, one way or another, to populate the Americas. The genetic connection between ancient Siberian and First American populations has been well-established within the last half-decade thanks to successful sequencing of ancient DNA from both sides of the Pacific.

There’s also agreement that the travel took place sometime within the last 25,000 years. That’s when, looking at the genetic data, scientists see that the Siberian and First American populations become genetically isolated.

It’s important to emphasize, however, that based on this isolation alone, researchers can’t determine that travel to the Americas was occurring that early. It is very possible that the people directly ancestral to the First Americans were still in Siberia, or in Beringia, simply separated from other populations for millennia before heading east.

While the coastal and interior camps agree on the basic background, the devil, of course, is in the details.

On The Move

Critics of the Beringia interior model cite recent geological and paleogenetic studies that suggest there was no way to travel by foot from Beringia into the interior of the Americas before roughly 13,500 years ago (give or take; different studies looked at different sites and different types of evidence, reaching slightly different date estimates). The Cordilleran and Laurentide ice sheets created an impassable environment for humans until that time, say anti-interiorists.

But a handful of archaeological sites in the Americas have been dated to be considerably older, including the Page-Ladson butchering site in Florida (about 14,500 years), the lower levels of the Gault site in Texas (at least 16,000 years) and Chile’s Monte Verde site (possibly 18,000 years). If humans arrived in the Americas from Siberia before an interior route opened, they must have come by boat, goes the argument.

Today's review of research looked at tktktk (Credit: Potter et al., Sci. Adv. 2018;4: eaat5473)

Today’s review of research looked at both human remains and archaeological sites stretching from Siberia to Florida. Fig. 1 inset appears below. (Credit: Potter et al., Sci. Adv. 2018;4: eaat5473)

That theory is all wet, counters the pro-interior route camp. The arguments against the coastal route have taken many flavors. Some of the more hardline critics claim artifacts from the earliest archaeological sites were either dated inaccurately or are products of natural erosion, not human hands. More moderate voices, however, suggest their pro-coastal, anti-interior peers have misinterpreted some important findings in recent papers.

Which brings us to a review of much of the most recent data from both camps, published today. The review looked at archaeological, paleogenetic and geological data published previously both for and against the interior and coastal routes.

The team’s conclusion: Simmer down, coasties and landlubbers, it’s possible you’re both right.

Speaking at a press conference Monday, review co-author Ben Potter, an anthropologist at the University of Alaska-Fairbanks, summed it up this way: “We can’t exclude either the coastal or interior route. Both could be used, actually; I suspect both probably were used. But again, that’s speculation…and we shouldn’t be as firm as some have been that we know the answers now.”

For example, Potter explained, the pro-coastal camp has interpreted dates in recent studies of roughly 12,600-13,100 years for flora and fauna along the proposed interior route as maximums — the earliest dates possible for conditions hospitable to humans. But the ages are just data points, and may not reflect when the interior route truly opened up to human migration. “The viability of the corridor could be even older; these are just the first actual dates that we have,” said Potter.

Meanwhile, back on the coast, a funny thing happens when an ice age ends: isostatic rebound.

When much of the planet’s water is frozen in ice sheets, sea levels tend to drop but, on a much more localized level, the sheer weight of glaciers can squash the land beneath and around them. Melt the glaciers and ta-da! The ground rebounds, springing up. The result: some coastlines from the Last Glacial Maximum (LGM) are actually above current sea levels. Thanks, isostatic rebound!

With better maps of where the LGM coastlines were, researchers have surveyed some areas that are now high and dry, looking for signs of human seafarers. All the sites found so far, noted Potter, have been at least 1,600 years younger than interior sites, and the style of the artifacts associated with these coastal sites appears to be derived from older material found in the interior.

Then there’s the lifestyle issue, noted Potter. All archaeological evidence from northeastern Siberia and Beringia suggests the people living there were hunting megafauna — bison, horse and mammoth — not megafish. There is no evidence of a maritime tradition in these populations, which are genetically closest to the people who did eventually make it to the Americas.

The Way Forward

Of course, a hypothesis is just that, and based on evidence currently available.

Last November, for example, a separate team advocating for the Kelp Highway model noted that much of the evidence for these intrepid seafarers, from Asia all the way down the coast of the Americas, was likely in sites now underwater (isostatic rebound is, again, highly localized, and much of the coastline that would have provided pit stops on the Kelp Highway is indeed currently under the sea). Underwater archaeology projects could turn up new evidence that boosts — or torpedoes — the coastal route.

What’s needed to determine how and when the peopling of the Americas really happened is a multidisciplinary approach, said Potter and his colleagues. Foremost in that effort will be working with indigenous communities to collaborate on the sampling and sequencing of ancient DNA, an issue that has been marred in the past by cultural differences, perhaps most famously with the legal battles surrounding the nearly 9,000-year-old First American known as Kennewick Man.

Sites tktktk (Credit: Potter et al., Sci. Adv. 2018;4: eaat5473)

A close-up of both archaeological sites and locations for geological and paleogenetic samples, including lake bed sediments, ancient plants and other material that has helped researchers build a more complete picture of the peopling of the Americas. The most likely overland route, between the Laurentide and Cordilleran ice sheets, is on left. (Credit: Potter et al., Sci. Adv. 2018;4: eaat5473)

Perhaps the most important moment of Monday’s press conference was one free of data points. Reflecting on the current state of the debate and why many researchers, and the public, seem to want a single narrative — coastal or interior — despite a lack of clear evidence, Potter said: “We would rather be intellectually honest and say both hypotheses should be on the table, more research should be done on both.”

He added: “I think the issue of ‘I don’t know’ is for many people not a good answer. And so an answer that might be incomplete or conflicting could be preferred over an answer of ‘I don’t know.’ As scientists I think all three of us here are very happy with ‘I don’t know’ because it pushes us forward to address the questions with new data and new analyses.”

Theories That Don’t Hold Water

By the way, at Monday’s press conference, the authors acknowledged that Beringia and the Kelp Highway are not the only two models for the peopling of the Americas. A few others are bandied about, most typically in sketchy YouTube videos that are light on sourcing. There has been speculation, for example, that Oceanic populations sailed eastward across the South Pacific, reaching Rapa Nui and eventually South America, and then continued to travel back and forth.

“There’s absolutely no evidence for that, and lots of counter-evidence against that,” Potter said.

Then there is the Solutrean Hypothesis, which suggests that groups of European hunter-gatherers suddenly decided to become seafaring sorts, left France and Spain, and boated west, following the edge of the sea ice, to the Atlantic Seaboard of North America sometime during the last Ice Age. The idea was based on perceived similarities between the stone tools of the European Solutreans and the Clovis culture in the Americas.

“People maybe have a misunderstanding about how much support that (hypothesis) might actually have within the scientific community,” Potter said tactfully. “It’s been tested and refuted on a number of grounds.”

While the Solutrean Hypothesis has never been widely embraced in academic circles due to an absence of compelling evidence, one place the theory has found a home is with white supremacists (so it’s got that going for it/sarcasm). For a great explanation of the numerous problems with the Solutrean notion, check out this thoughtful commentary from one of the researchers involved in a recent documentary that reignited the issue.

The review by Potter and colleagues appears today in Science Advances.

CATEGORIZED UNDER: Living World, top posts
  • Uncle Al

    reaching Rapa Nui” Observe evidence, then theorize. Rapa Nui / Easter Island / Isla de Pascua: The nearest mainland is central Chile, 2182 miles distant. The nearest population is Pitcairn Island, 1289 miles distant. Who were the ancient population?

    …Rapa Nui mo’ai
    … Shtreimlech

    Lost tribe of Israel.

    • OWilson

      Lord preserve science from the arrogance of certainty in theoretical hypotheses! :)

      Text books are being re-written all the time.

      • Uncle Al

        Lost tribe of Pacoima?

        • Normandie Kent

          Yes, The Native American people who lived in Pacoima would be the Tonva people, also known as the Gabrieleno and Ferdinandeno.

    • TLongmire

      Human beings have the potential to view the physical world outside of their body. Remote viewing is the reason the Nazca lines exist and how that island was found.

    • mlmontagne

      There are people living on Easter Island who are related to Polynesians. They clearly didn’t fly there, so they must have come by boat. Some South American coastal Indians have words in their languages, particularly words relating to boats, that are clearly of Polynesian origin. Given that the Polynesians reached Rapa Nui, there is no reason to suppose they stopped there. Indeed, they might well have reached South America long before they even found that little spot in the ocean. Either way, there was clearly contact between Polynesia and South America, but it was initiated *after* America had already been populated.

    • peterjohn936

      Chickens. Chickens in Central and South America are Asian chickens not European Chickens.

      • neoritter

        A path of travel from Asia to America has been established though, so that bit alone doesn’t support the Pacific maritime route to the Americas.

        • peterjohn936

          No it hasn’t. Berginia is currently under water so there is no evidence to back their hypothesis. For some godforsaken reason archaeologist think they had to walk because there was no way primitive man could built a boat. They can weave fabric, domesticate plants and animals, make jewelry, and make weapons, but they can’t make a boat. BTW, the current ice age is about 3 million years old so why did man only make the journey recently?

  • cgray

    Just had to end the article with the “REPUBLICANS ARE NAZIS!!!!!” propaganda. If you enjoy eating zoo animals, just move to Caracas. I’ll pay for your ticket. Literally.

    • Uncle Al

      Blue Tide, Free Ride! got nothing this past Tuesday. Citizens,patriots, exceptional Americans…We are all Trump. Never vote for a Democrat.

    • mlmontagne

      Where do you read that into this article?

      • cgray

        “White supremacists” is Democrat Party code language.

        • mlmontagne

          But there was absolutely nothing political about the article. This is a *scientific* article. To jump and assume that every use of the term “white supremacist” is political is just like those who assume every use of “white” and “black” is racial.

        • Cjones1

          Since the legacy of the Democratic party is slavery, racism, and segregation, the party name is as symbolic as any Confederate flag or statue.
          The Solutrean hypotheses was based on similarities between Clovis flint point design and European (Solutrean) flint point design. There was no conclusive genetic link between the 2 groups.
          The proliferation of diseases in the Americas after Columbus’s voyages should have been duplicated in earlier contact with non-American populations. The book on the Americas is a story in progress.

      • Mallet Head

        For someone who touts the ability to interpret American Indian creation myths it seems odd you could miss the gratuitous inclusion of the last paragraph. The article could have ended the paragraph before, it didn’t, toss in the remark about white supremacists. Who are they? Leftist? Liberals? Socialist? Democrats? Who? If one doesn’t get the hint it links to an another article whose topic heading calls consideration of the Solutrean Hypothesis racist. Again who are these racist? Review the list above, is it them? If you still haven’t figured it out follow our friend cgray’s advice watch CNN for five seconds.

        • mlmontagne

          I am not aware of any white supremacist influence on the Republican Party. The article said nothing about the Republican Party, or any other political subject. The Solutrean Hypothesis has been very thoroughly discredited and I have no doubt that the only people who cling to it are racist nutjobs. To say so says nothing about the Republican Party. To say that it does is precisely equivalent to those who see race in ever mention of the words “black” and “white” in any context whatsoever.

          • Mallet Head

            If you are not aware that Republicans are labeled racist at every turn and liberals/all leftist are supposedly champions of minorities then you have missed out on the last 60 years. Or.. you are being willfully ignorant. Well, ok, you could be totally out of touch with political reality.

          • mlmontagne

            Of course Republicans are so labelled, that doesn’t mean every use of the term is a reference to us. There are white supremacists in the world. Some of them do like that theory. In this context, it was a totally non-political statement.

          • Mallet Head

            “Of course Republicans are so labelled ..” now we’re getting somewhere ..

            Next step. White supremacy is a political movement. Any comment on a political movement is then political. When you go out of your way to bring them into an unrelated topic doubly so. What was the purpose of bringing them in. What irks the author, those at the seminar, readers here about a fringe group, relatively small in number, that they must give them life in a forum they didn’t have. Virtue signaling? Which is only the subtle or soft furtherance of an ideological agenda. What I initially objected to was, as a lay person, who enjoys these kinds of scientific articles and have come across the Solutrean Hypothesis in the past. Suddenly with out prelude I’m a racist. Why? Cause I didn’t get the memo SH is discredited? Yes I took it personal. It’s a layman’s magazine whose target audience are scientific laymen written by an author targeting scientific laymen. Why the hell am I being called a racist? Why couldn’t she have left it at SH has been discredited. No, she was making a point, whether she admits it or not. Whether it is causal or unconscious bias, to use the left’s terminology, there it is. Of course I expect no sympathy for this view.

          • mlmontagne

            I disagree. It was merely a statement about the hypothesis, a necessary one to establish that it has no scientific basis of any kind, and is only ever brought up for one reason.

          • Mallet Head

            oh yeah sorry I didn’t understand proof of a non-scientific basis rests with white supremacist embracing it. Boy do I feel silly. Obviously racism is the single reason to believe this, it never could be that in a magazine whose target audience is scientific laymen, causal followers, hadn’t heard its been disfavored. I agree, gotta be racism, nothing else fits.

          • mlmontagne

            Yeah, pretty much. There is nobody who doesn’t know the Indians came from Asia. Anybody who claims to believe otherwise is kidding themselves for some reason.

    • JerseyCowboy

      What’s funny is that anybody who is aware of these theories on the internet knows that there is an even more widespread theory by non-white people, especially black nationalists, that it was black people who populated America, and Africans who sailed across the Atlantic. That is the most common theory I see online. Any actual archaeological or genetic evidence is invalid because white people invented those sciences.

      • peterjohn936

        Actually Egyptians, Phoenicians and Carthigians are likely since they possess ships capable of traveling the high seas thousands of years ago.

    • Randy McDonald

      Why did you assume that Republicans were white supremacists?

      • cgray

        Google it. Or maybe watch CNN for five seconds.

        • Randy McDonald

          I was referring to the original commenter upthread, who assumed that a reference to contemporary white supremacists was to Republicans. That easy assumption made by him, I think, is noteworthy.

      • Erik Bosma

        How (and when) did they get here?

        • Erik Bosma

          I mean Republicans (and Democrats of course).

    • neoritter

      There’s a more tactful way of putting this, but yeah, the last paragraph was unnecessary. We shouldn’t be discarding theories because some unsavory individuals or groups (to put it diplomatically) like the theory.

      • GemmaTarlach

        The last paragraph does not in any way suggest that the Solutrean Hypothesis was discarded because any given group liked it. The last paragraph explains that the Solutrean Hypothesis was discarded by scientists because it is not supported by any evidence but that, despite the fact that everyone else kicked it to the curb, it is still liked by a group because it fits that group’s decidedly unscientific ideology.

        • neoritter

          You can try and rationalize it all you want. There is no need to bring politics into a discussion about scientific theories. Who supports it and why has, or should have, little to do with why a theory is not widely accepted or believed. To use a phrase by others, that line is a dog whistle to people that those who might support the theory are obviously not supporting it because of rational thinking but because they’re racists. It’s like if I said, the heliocentric theory is not widely supported by academics today, but one area where it has gained a following is with Godless heretics.

      • cgray

        I gave up on being tactful when Democrat Party terrorists starting shooting Republicans on baseball fields.

      • Normandie Kent

        They are not discarding Theories or hypothesis because of a distaste for racist hijacking , but because after a hundred years of hypothetical Europeans, or Hebrew Sea farers, there has been ZERO evidence to back up this wishful myth making.

        • neoritter

          The point, you miss it.

    • GemmaTarlach

      My post has nothing to do with Republicans. Nothing. Zip. Zero. Zilch. My post does not contain propaganda promoting any ideology or agenda. It is providing readers with a summary of new peer-reviewed research and a related press conference during which discussion of the Solutrean Hypothesis was raised. Literally.

      • Bamko

        When I got done reading your article (of interest to me, I have a lot of probably stupid questions because of the South Pacific stuff I read over the years) I then went to the comments. I was surprised they were talking about politics. I did not read any of that into the article. I think too many people are just trolling the internet with their preconcieved arguments looking for a place to yell them. I am sorry it was needed for you to explain your article was not about politics. It should not have needed to be said among reasonable adults, IMO.

      • Mallet Head

        Aww gee fellow guess what you are hereby charged with a microaggression and unconscious bias against whites which, of course, isn’t racism at all. No one can ever be charged with that. Yet there it is. What exactly was the point of throwing in the bit about white supremacist. What exactly did that have to do with anything? Oh yeah a press conference discussed Solutrean so it was really, really gawdamn important that you mention it.

        • Randy McDonald

          If you were aware of the way in which white ethnonationalists use the Solutrean hypothesis to discredit the idea that the indigenous peoples of the Americas are indigenous to their ancestral homelands, you might think differently.

          • Mallet Head

            This was an article about the populating of the Americas. Where did racism come in? The author brought it up not white ethnonationalists. It’s like this, as an example, there is a show called Ancient Aliens. On this show there is not one single edifice, not one single genius, not one single achievement what isn’t attributed to Aliens. Since most of this is really attributable to the ancestors of what are now third worlders and other non-whites why isn’t this racism? If ‘other worldly visitors’ did all this the implication is the mostly non-white people were to stupid to have done it themselves. Why isn’t ABC/DISNEY/A&E called to account for hosting racist views? Why doesn’t every article touching on these subjects carry a virtue signalling racist believe this stuff? I’d argue there are thousands times more air heads believing in Ancient Astronauts reading Discovery than believing in white supremacy. A greater threat to scientific thinking is the racist cult of Ancient Aliens. It is that easy to label people racist for believing in discredited ideas. That’s why I took it personal. I’ve read about the SH before, thought, that’s neat. Next thing I know I’m a racist. Where did that come from, slap in the face. Why do I feel what’s expected of me is a either a full confession of my racist ways or a full denunciation of what I never claimed to be in the first place or both.

          • bibol

            Many indigenous peoples of the Americas are not indigenous to their ancestral homelands. The Apache and Navajo move from what is now called Canada. In the 1200-1500’s time era. Many others moved when they received the horse

          • Normandie Kent

            4 tribes out of the literally hundreds do not represent the bulk of NAs that HAVE been living on their ancestral homelands for 5,000 to 10,000 years. Unlike the the descendants of the Euro tribes who barely moved into Europe from central Asia 4,000-2,500 into western Europe, and a mere 500-150 into the The Native American homelands thru mass immigration. Europeans have been immigrating into other native peoples homelands non-stop, homelands for thousands of years now!!

          • bibol

            There are a lot more that moved. Even the Aztec a empire that tribe had to ask permission to move into the swamps. When the so called Europeans moved from Asia. Who do you think lived there on the ice.

      • Randy McDonald


  • mlmontagne

    Somewhat related. Some years ago, I got interested in American Indian folklore and read as much of it as I could. In my reading, I noticed something about their creation myths. The stories were as varied and diverse as you might expect, but they all had one detail in common. In every single American Indian creation myth that I have ever come across, human beings are not created with the world. They are always already existing, somewhere else, when the world is created. Whether they are alive in the Happy Hunting Grounds, living in the sky, asleep in a cave, or whatever, they are already existing and have to be taken by the gods, from where they are, and placed in the newly created Earth.
    It has always seemed to me that, aside from indicating that all the stories descend from a common original, this also indicates that they represent an actual oral history in which the original tellers were *aware* of the fact that they had gone from one distinct place to another. I have always wondered how they might have known that. Now that I see that the migration route would have involved travel through a fairly restricted corridor, from one wide open area to another, it makes sense. If any folklorist or anthropologist reading this wants to do a proper study of the idea, feel free to use it.

    • TLongmire

      I think what you noticed is that the Native Americans were not indoctrinated into any “literate” philosophy but rather forced to imagine their own “creation”. I have always had a memory of standing before a “devise” with other people around and being asked “who’s next” and everyone hesitated so I touched the devise and became “me”. Whatever this is is not the cutting edge but a divergent path.

  • peterjohn936

    Both sides act as if they were there to see the migration. They weren’t.

  • J. G.

    It’s sad that in a scientific article of fact-based inquiry we cannot, from the conversation below, get past political and ideological matters. But I have to admit, the authors invited it. Shame on them and on for allowing it. Especially so as both disclosed their anti -conservative, anti-Republican bias in doing so.

  • Balbino Hernandez

    Once again Libtards can’t stop themselves…..

  • David Whitney

    It just breaks my heart to read so-called scientists debating these questions, revealing their lack of basic curiosity and/or common sense.

    1. They haven’t found the Siberian fish bones because they don’t know where the Siberian coast was at the time.

    2. Who’s to say there wasn’t a previous human population before these disputed migrations happened?

    3. Have they given up on the theory that humans hunted every large land mammal on both American continents from the densest jungle to the highest mountains, from coast to coast, from the Canadian tundra to Tierra del Fuego, to extinction in the space of 200 years?

  • Erik Bosma

    They came through Beringia (many times), they crossed the Pacific (south and north and middle), they probably crossed the Atlantic (north and perhaps south) and they walked across the Arctic. And some did this twenty thousand years ago maybe a lot more. Any more questions?

  • kieron George

    Weren’t the Solutrean people still black though?


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