[BMorearty]

I'm confused by this article. It says "New evidence adds to work showing people made these prints [in New Mexico] sometime between 21,000 and 23,000 years ago." It supposedly contradicts experts' belief for decades that "the first people in the Americas migrated from Siberia across the Bering Strait on a land bridge exposed during the last glacial maximum, sometime between 26,500 and 19,000 years ago.

How is that contradictory?

[jcranmer]

The traditional thesis of the peopling of the Americas is that people arrive in Beringia (not entirely accurate to say they crossed the Bering Strait--there was no Bering Strait, and Beringia was where the Bering Strait is now!), c. 20-odd thousand years ago. About 13,000 years ago, a gap opens between the Rocky Mountains and the Laurentide Ice Sheet, and settlers traveled through this "ice-free corridor" to reach what is now the US, where they flourish as the Clovis culture. This is known as the Clovis-First hypothesis--that Clovis was the first material culture to leave Beringia and people the rest of the Americas.

However, there's a lot of evidence that people had spread out to the rest of the Americas well before Clovis, and it's now known that the "ice-free corridor" opens up too late--it opens up even after we see traces of Clovis-First. By around the 1990s, the anthropological community has accepted that Clovis-First is complete and utter rubbish, although there is still disagreement about the timetable. I'd wager seriously arguing Clovis-First among scientists would get you as much derision as seriously arguing geocentrism among astronomers.

Annoyingly, popular anthropology lags science tremendously. It probably took a decade or two for textbook writers to bother to update their textbooks to consider the rejection of Clovis-First (hell, when I was in school, the textbook didn't even bother to present alternative hypotheses than Clovis-First, although our teachers were knowledgeable enough to tell us in class that, well, textbook's got it wrong there), and then perhaps another decade for schools to get around to new textbooks. It's still the case that virtually every popular treatment of some new press release about dating controversy in some ancient human habitation site (there's one every year or so) starts, as this article does, by talking about how it potentially nails the coffin for Clovis-First. (Wake up science writers! That coffin's been nailed shut for longer than most of your readers have been alive!)

[civilitty]

To add to that great explanation: those ice free corridors were important because during the glaciation there were vast expanses of ice with zero vegetation or animal life, making it impossible for humans to cross without starving to death. Those glaciers essentially looked like the South Pole - nothing but ice for hundreds of miles. How humans managed to get so far and colonize so much of the continent while it was still iced over is one of the great "mysteries" of the new world.

It took plants and animals thousands of years to colonize Berengia before it was possible for humans to cross the expanse on land so the main competing hypothesis states that the people of Oceania - at this point very capable of navigating at sea and exploiting marine resources - were the first ones to make the trip, hugging the coast of Beringia to navigate and wait out storms but eating seafood caught at sea to stay alive.

Unfortunately the sea level at this point in time was at least 150 ft below and while underwater archaeology has had somewhat of a renaissance, there's still very little evidence to support what many (most?) archaeologists expect is true: human arrival in the Americas predates any evidence we've recovered by many thousands of years.

[AlotOfReading]

As someone who actively follows this literature, I've never heard of the oceania "theory" put forward by anyone writing in this century. I can think of some very old books by people like Thor Heyerdahl, but they're obviously not remotely legitimate scholarship. What have you read that says it's a mainstream hypothesis?

It doesn't make much sense either, as all of our South American aDNA (e.g. Los Rieles 10900BP) is highly related to other American populations. We also know that boats and marine resource exploitation were used in Northeast Asia prior to the crossing period, given the whole PSHK complex thing (whether or not they're truly ancestral to the first americans). They would have been much better positioned than the people of Oceania, who had just barely colonized the nearest few islands off Sahul and did not leave behind much to suggest particularly advanced marine exploitation at this point.

[civilitty]

Derp! I may be using a more expansive definition of Oceania due to my native language. I think the correct group would be (South) East Asia

[BMorearty]

Thank you. That is a much more lucid and complete explanation than was given in the article.

[AlotOfReading]

You couldn't get from beringia to New Mexico during the last glacial maximum because of all glaciers in the way.

The dates given for the LGM are (very roughly) when Beringia was accessible from Siberia. Pinning down when humans were able to access the rest of the continent is tricky, but current estimates for that are sometime between 20-18kya at the earliest based on genetics. Dates based on material culture evidence are even later than that, which presents done obvious problems with the dating on these footprints.

There are also pretty hard constraints on the other side for humans even arriving in that part of Siberia, since the immediate ancestor sites with sequencing at Yana and Mal'ta are from 32kya and 25kya respectively.

[doodlebugging]

If those early people had boats or other means of floating along the coasts they easily could've found their way to present-day New Mexico during the time period in question with or without glaciers in North America. A single family or individual who managed to hug the coast to a point south of the glaciers could easily walk the width of the United States in under a year averaging only 10 miles per day. There is plenty of time for a nomadic person or group following game animals or just walking over the hill to see what they can see to cover the entire United States on foot in a short lifetime. If they have rafts, boats, or any other way of navigating waterways without drowning it is even easier. These people were not stupid and they likely were as curious as we are today. They didn't have the cool technologies that we have today or in the last 200 years but they had a deep knowledge of their environments and could read the landscapes, the skies, the animals, and the plants and understand a lot more than most of today could.

The real question needs to be about how far back we can go and say conclusively that humans built boats, hollowed logs, etc. and used those constructed contraptions to travel over water.

[AlotOfReading]

It's not nearly as easy as you think [0]. I'm not going to cite the whole library of work on this topic because that comes across a bit rude, but there's been a lot of ink spilled here and I'm summarizing heavily for brevity's sake.

Humans had likely already invented boats, given that they reached Japan and Australia tens of thousands of years previously. The North Pacific was just a deeply unfriendly place during the LGM. There were few resources, frigid weather (Beringia itself was practically temperate in comparison!), and they'd have to fight a strong Alaska current all the way down the coast.

It's pretty clear at this point that the coastal route happened eventually, but we need a lot more data to put together a sensible theory that can reconcile these outliers.

[0] https://doi.org/10.1073/pnas.2208738120

[tzs]

Looking at it from the other direction, humans reached North America before the wheel, and before domestication of any animals except possibly dogs. Traveling a great distance by land would then mean either carrying your stuff or dragging it possibly on a sled maybe with dogs to help.

I'm not sure boats are old enough, but rafts definitely are. Humans also had rope well before then, and string even longer. A boat or raft train down the coast seems feasible, and would let you let you bring a lot more of your stuff.

Fishing is also old enough, which might make picking traveling by water a more attractive choice than going by land. Going to some far away unknown place by land runs the risk of having to cross mountains or deserts along the way where food may be scarce. (And that's another advantage of a water route--no mountains).

[AlotOfReading]

Much of the Alaskan and Canadian coast was glaciated during the period in question. You should trust me that doing a raft train along the live edge of sea ice is a very quick way to die.

[doodlebugging]

According to the paper sea ice was a seasonal consideration during the LGM. There was open ocean during the summers. If these people were fishermen they would have all the skills and motivation to follow the fish wherever they led. Since the circulation in the area of interest is cyclonic, or counterclockwise, a boatload of people would naturally be carried to the central Oregon coast if they launched from Beringia off present-day Kodiak Island. The whole journey, assuming as I tend to do that systems operate today in the same fashion that they operated back then, (uniformitarianism) has those people making landfall about 90-120 days later riding the ocean currents. That sounds reasonable.

The thing that I most wish would change in archaeology is the dumbing down of people who lived a long time ago. The very truth of their survival in situations where few of us modern people would thrive or survive tells modern people everything they should know about our common ancestors. They were ignorant only of the things that we all take for granted today - paved roads, wristwatches, computers, air conditioning, automobiles and engine power, etc. They were masters of their environments who learned by doing things with their hands and by listening to the oral histories of their heroes and internalizing that knowledge so that they could thrive if confronted with similar challenges in their own lives.

The fact that sections of the trails they took to get into North America have been erased since they made their epic journey is entirely due to everyday processes like erosion, inundation, etc. When we find a new site with outlier dates we should consider that we are constrained by the sparse sampling in the data driving our determinations of climate conditions during that period. We don't have high enough resolution to define seasonal variations so we can't say with confidence that it didn't happen during a summer's journey to a group of people who just followed the roving food supply wherever that led and laid in enough supplies to last them thru the winter that they knew was coming.

[doodlebugging]

I agree. They could've used inflated sealskins for pontoons for a large raft and we would not know it today unless we happened to find one stuck in an anaerobic mudflat. There is so much to learn that I think it is too early in the game to discount anything.

[doodlebugging]

I think the main difference in our respective opinions is one of time scale.

You seem to stick with the paper in your focus on long time periods representing several hundred generations and the things that could limit or prevent human arrival or presence at the location during the time period proposed.

I am focusing on things that could plausibly happen to a nomadic group within a single human lifespan. It doesn't matter where on the time line one would place the nomadic group, these achievements are possible and the dating of these footprints using three complementary methods which all yield similar dates strongly suggest that people did in fact make it to New Mexico by that early date.

We will never know how they arrived unless we can find new sites to confirm a likely path of travel. They may have followed the coastline south in boats stopping wherever they found shelter and food. They may have used sleds or travois to move their worldly possessions cross-country over any terrain whether ice-covered, tundra, forested, or open plain. We know that they were adaptable and they were closely in tune with their environments, with a deep understanding of seasons, wildlife, plants, and weather. They had to be just to be able to make the trip to Beringia or to eastern Asia. Their knowledge had to be encyclopedic and like most knowledge in ancient cultures was almost entirely passed generation to generation orally. There are still cultures who pass these traditions orally, keeping alive the old knowledge and skills. [0]

We know nothing about the normal divisions of labor within a group but we do know from direct evidence that people did in fact make the trip overcoming all of the challenges they found along the way. Where they went after leaving those tracks is anyone's guess and is up for future discovery, just like the path they took to get there.

I read the paper that you linked. I appreciate the link.

I agree with your final sentence:

>It's pretty clear at this point that the coastal route happened eventually, but we need a lot more data to put together a sensible theory that can reconcile these outliers.

Though you and I reach different conclusions we can agree that a lot more research and discovery is needed to understand how these people arrived in present-day New Mexico that long ago.

I found on reading it that the paper did not discount the possibility that people followed the coast south or that they traveled overland for the entire journey into the interior of the North American continent during the time period when these tracks were probably made, LGM. In fact in the sections where they addressed this question they hold open the possibility that humans could have taken advantage of seasonal variations in sea currents, glacial meltwater flows, local warming of land routes, etc to make the trip.

Their data does not have a high enough resolution to answer the question of whether anyone attempted the journey successfully or unsuccessfully. Their resolution is on the scale of millenia whereas one would need seasonal data for insight into the answer. I guarantee that the humans that left those footprints had a detailed knowledge of seasonal variations in local conditions and they took full advantage of that in order to secure their survival.

I look forward to reading more about efforts to nail down when and how early humans made the journey into North America and to find out how they fared on arrival. I'm a geoscientist but I have always loved archaeology.

[0] https://hakaimagazine.com/features/with-old-traditions-and-n...

[AlotOfReading]

Responding to both this post and the other one. The thing is, I don't discount that they were masters of their environment and highly adapted to it within the limits of their technology. My point is that this is an incredibly, unbelievably hostile environment. I've had friends who have worked up on the ice with Inuit. I've visited the high arctic myself and organized high latitude expeditions somewhat farther south. The frostbite from those experiences was more than sufficient to give me a deep respect for the environment.

That's today, with modern equipment and a relatively tame polar climate. The coastal North Pacific during the LGM was an entirely different beast. We don't have a lot of direct evidence from Beringian populations during the LGM. What little evidence we have from their immediate ancestors in Siberia is that the onset of the LGM caused severe regional depopulations, with most survivors seemingly fleeing to refugia like PHSK, inland Beringia, and the south. There's still an open debate whether this depopulation was total (as in no human habitation of the region) or merely near-total, with most scholars leaning towards the latter these days. Humans definitely struggled.

----

But assuming you're a Beringian survivalist who wants to run down to Oregon for some salmon, how would you do it (assuming a reasonably modern understanding based on Inuit adaptations)?

First, you actually want sea ice, not to travel along the land-bound glaciers during summer. Land-ice is dangerous, full of crevasses, and usually far from flat. The fjords and sounds of the modern high arctic are semi-inaccessible near large glaciers even to modern Inuit due to the dangers of summer icebergs. They usually wait until winter or spring to hunt and fish in these areas. However, it's the LGM and you probably don't have the incredible cold-weather technology of modern Inuit (better than most commercial jackets we can buy). Whatever boat you're using also isn't going to survive the oceanic storms either. Most modern boats can't. Both of these mean winter's out, even though it's the best travel season today.

However, there's a brief period between the end of winter and the beginning of summer other places like to call Spring. The ice is increasingly dangerous as the season progresses, but it's traversable and you can shelter in the unglaciated coves during the summer as you head south. You repeat this for years and maybe you can get enough people south of the ice to survive before the ice age rears its head again and collapses the fragile marine ecosystems you rely on by starving them of sunlight with permanent sea ice.

It's possible, but unbelievably tough. Why would you leave the relatively temperate Beringian climate for this kind of hell? The paper's implicit answer is that things might have been just good enough for a short while that this was plausible, even with all the ecosystem recovery that had to happen to make it a viable route.

----

Alternatively, you go way the hell out past the Aleutians into the middle of the Pacific to try and catch a current back south. If you hit a storm, you will almost certainly die. This is technically possible, but it stretches the bounds of credulity to believe a viable population got south of the ice this way.

----

The paper doesn't really get into these kinds of specifics because, well, climate paper. It's very hard to get high resolution climate results, so I'm impressed that the data is even this good (as an archaeologist).

[doodlebugging]

I appreciate you taking time to read all that and compose a well thought out reply.

I understand the challenges these people would've faced dealing with local environmental issues common to the seasons they experienced. I wish we had more examples of the tools and technologies available to them so that we could write accurate stories about how they survived and prospered or simply endured. The important thing though is that we know they dealt with all their challenges and survived. These people were resilient.

I think the large collection of footprints at White Sands tells us that it is not necessary for a viable population of humans to make the journey, only for a single small group. The fact that there are multiple levels of tracks of humans and extinct land animals together supports the conclusions one could draw from the materials used in dating of the tracks and implies that those who made the journey went on to occupy the region for generations.

It's a fascinating subject and there will be more debate over the years but I think archaeologists will come around to the notion that modern man found his way into the interior of North America a long time before or at some point during the LGM and they found a home where there was a mild climate supporting plenty of game and shelter and they took advantage of that.

That is the reality of the tracks at White Sands. Some people took an opportunity to go south and once they completed that challenge they found themselves in a land of plenty and they made themselves at home. Whether they built a boat and sailed icy seas hoping for the best, or followed local game south overland across thawing tundra during a warm spell is something we will need to study. Maybe they just picked a leader like our Dads who couldn't find his way to the grocery store without a map and would never admit to being lost and eventually, after following this guy for months they found themselves south of the ice and the end morraines in an area with abundant game and at that point they composed their first songs and oral histories to tell the tale of their survival and rebirth in a new land of plenty.

As a historical novel it would be great.

[kylebenzle]

What a great comment! I love needing to remind myself of this, that a person can walk across the US in about a 1, but over 2 years would be relatively leisurely.

[doodlebugging]

Thanks!

I think most people have not hitchhiked cross-country or spent a full day walking. Too many of us have never been motivated by hunger or thirst to see what was over the next hill. We just do a quick search for a 7-11 on our smart phone.

In contrast, these ancient people would understand how to use acquired knowledge and local resources to insure their survival, to deal with unfamiliar animals or plants, and to safely navigate unfamiliar terrain. This would be second nature to them.

[lumost]

Something that has never sit right with me. Why do we not have clear evidence of past major civilizations in the main habitation zones of modern North America?

Shouldn’t we see ancient cities in New England, the PNW, Bay Area, and southeastern US? What made South America, and the southwestern zone of North America special in this regard?

[jcranmer]

North American agriculture appears to have been cursed with poor cereals for cultivation--basically none of those crops survive today as major cereal crops, unlike all the other agricultural hotspots. Corn doesn't arrive until ~1000, and the arrival of corn radically alters the makeup of North America.

Cahokia is the largest city of North America (peaking at probably 10-20k people), starting about 1050, peaking perhaps 1200, and being completely abandoned by about 1350 for unknown reasons. And after Cahokia, there's... no other major city. Mississippian sites in general decline in size, and there seems to be a general aversion to urban centers. It's hard to make out what is going on, because then comes catastrophic European contact that destroys all of the cultures with only fragmentary evidence of contemporary lifestyle.

One theory that I've heard is that we're seeing what is essentially the endgame of proto-civilization: the North American cultures are trying out alternatives to urban, territorial polities. Perhaps something akin to Greece during the Greek Dark Ages. If European contact had come two or three centuries later, we might have seen the emergence of territorial states in North America.

The exception to this in North America is of course the Southwest, which was in cultural contact with South America and Mesoamerica. Corn arrives to the Southwest far earlier than the rest of North America--maybe 2000 BC at the earliest, although it doesn't clearly hold until about 500 BC.

[anthonypasq]

this seems so bizarre considering how incredible fertile the midwest is considered. you'd imagine the mississippi river system had enough geographical advantages to support the number of people you would see in China or India

[AlotOfReading]

Cities has a particular connotation of dense, urban areas and it's not necessarily the only way high population density can exist on a landscape. California is a good example here, with some of the highest precolumbian population densities in what's now the US. Most of those people lived in Central Valley in large villages often exceeding 2,000-5000 people. However, there was very little high level political organization compared to say, Central Mexico and their primary food sources fall outside typical definitions of agriculture (though they were definitely intensive and involved lots of complicated plant management).

Within the Bay area, populations were centered around exploiting marine resources. Hundreds of large shell middens dozens of feet high littered the precolonial coast, most of which are now destroyed. Even pleasanton, far inland, harvested marine resources because it was a swamp filled with fish.

The PNW still has extant remains of massive precolonial villages, like Ozette [0].

The Southeast/Midwest was another case where we have massive villages, in some cases supporting 10s of thousands of people.

Etc. We don't see these today because we quite literally built on top of them. I used to live near a suburban neighborhood built atop an old Hohokam village where thousands of cremations had been recovered. None of the residents I met knew that the "hill" in the middle was the bulldozed remains of the Pueblo.

[0] https://en.wikipedia.org/wiki/Ozette_Indian_Village_Archeolo...

[rawgabbit]

AFAIK The native peoples of the Americas did not have iron technology. The Incan and Aztec empires were able to feed their peoples despite being limited to stone and wood and obsidian.

I believe the forests of North America could not be farmed without iron axes and saws.

[AlotOfReading]

They did, and the people of the PNW specifically worked drift iron. The wiki page on precolumbian metallurgy is worth reading through, because the true extent of metalworking was fairly widespread [0].

In most cases, stone was preferred to metals because it was abundant, sharper, and cheaper, much as we use iron extensively today despite Aluminum and Titanium alloys being better in many respects. The areas that did work metal heavily (e.g. west Mexico, the triple alliance, Ecuador) typically used it for ceremonial objects and small domestic tools like needles.

[0] https://en.wikipedia.org/wiki/Metallurgy_in_pre-Columbian_Am...

[diogenes4]

I believe that "sometime between 26,500 and 19,000 years ago" is an appositive marking the beginning of the land bridge's accessibility, not the time of migration. What they should have said is that the broadly accepted conservative time frame for migration is somewhere between 14kya and 19kya, as the white sands footprints have dating issues that complicate accepting them at face value. The liberal interpretations of the evidence—especially in northern Canada and Alaska—can push evidence back to more than 33kya—I've seen dating for 44kya, iirc, which is very contentious and not broadly accepted.

That said I don't have a wapo subscription, so that's my best guess.

[hn_throwaway_99]

You can read WaPo articles if you turn off Javascript.

[hinkley]

It wasn’t so long ago we thought 12500 years was about the right time.

[AlotOfReading]

It's been well over a decade since Monte Verde became widely accepted (2008-2010ish). Only a couple more years till it can vote.

[hinkley]

It’s been decades since most people here took a natural history class.

World is full of doctors spewing fifteen year out-of-date medical knowledge. Not everyone is going to be up on recent-ish events in your little niche. You’re in for a lot of rough conversations.

[JKCalhoun]

FWIW, WaPo loads fine for me with Reader turned on (Safari).