Ancient Diets, Human Carnivory, Mammoth Hunting, Clovis Culture & Origin of Native Americans | Ben Potter & Jim Chatters | 199

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About the guest: Ben Potter, PhD is an archaeologist & Professor of Anthropology at the University of Alaska-Fairbanks. James Chatter, PhD is a retired archaeologist and paleontologist. They recently published a paper on the diet of the Clovis people of North America at the end of the last Ice Age.

Episode summary: Nick talks to Dr. Potter & Dr. Chatters about: the Clovis culture and initial human colonization of the Americas; human diet since the last Ice Age; ancient human diets; hunting of Mammoths and other large herbivores; Clovis technology & culture, including projectile weapons; and more.

Related episodes:

* M&M #160: Diet, Hunting, Culture and Evolution of Paleolithic Humans & Hunter Gatherers | Eugene Morin

* M&M #154: Evolution & Genetics of Human Diet, Metabolism, Disease Risk, Skin Color and Origins of Modern Europeans | Eske Willerslev

*This content is never meant to serve as medical advice

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* Episode transcript below.

Full AI-generated transcript below. Beware of typos & mistranslations!

Ben Potter 3:12

Sure, I'm Ben Potter. I'm a professor of anthropology up at University of Alaska Fairbanks, and my research mainly is in bridging archeology, but I'm very interested in the peopling of the Americas, and I've written on the archeology and the genetics relating to that.

James Chatters 3:29

And I'm Jim chatters. I'm an archeologist and paleontologist working out of the Seattle area in Washington. I'm also secondarily affiliated with McMaster University, where I serve on doctoral committees.

Nick Jikomes 3:46

And so you guys have, you know, we're going to talk about a recent paper, but also how that hooks into, I think, a more general and wide ranging body of work that that you guys are a part of, to do with, with human pre history. And I think much of what we'll talk about here is essentially the the human pre history of North America, how people got into North America, what they were doing when they were there, who they were, and all that stuff. The the new paper you talked about, focused in a lot on what people were eating in that time, which is a fascinating subject, and it connects into a lot of stuff that I cover on the podcast, including diet metabolism, what people eat, and what the metabolic consequences of that are. But the sample that you work with on this new paper is from something called a Clovis person, someone who lived during this Clovis period of history. Can one of you just give us a brief overview of what was a Clovis culture? What time period are we talking about here, and what are the sort of, just the broad strokes of what we know about those people. You

James Chatters 4:48

want to take that one? Ben,

Ben Potter 4:49

well, you go for it. Jim, you're more closely associated, oh, right

James Chatters 4:53

down here, south of the ice. Yeah, COVID is the first and really the. Only continent wide cultural manifestation that we see in the Americas, in North America, and it extends from the southern margin of the glacial ice so in parts of southern Canada all the way down to Northern Venezuela. It is characterized by a trianguloid, large triangulate, fluted spear points, that is for the haft and groove, large knives, bi facial knives, end scrapers with little spurs on the edges of them for grooving bone. And it's also found with, frequently found with large bone, ivory or antler or shafts. It's seen frequently in association with mammoth remains at kill sites. Mammoth bones are easy to see. People find them. They get excited because they're bigger than modern animals, and so mammoth kills are are frequently reported, and there are 14 of these known. But it's also found as scattered spear points throughout the eastern United States, and few small campsites have been found, very ephemeral campsites where people stayed for a very brief period of time, maybe a few weeks at most, before moving on.

So it's a highly mobile what appears to be hunting based culture between roughly, depend on who you ask, between 11,000 412,700 years ago,

Nick Jikomes 6:41

I see. So we're talking about 11 to 12,000 years ago, give or take. And these people were basically all over the Americas, a very large extent. And they shared sort of a common culture in terms of, like the tools and the artifacts and the lifestyle they seem to be leading.

James Chatters 6:56

Yes, very much the same sort of thing everywhere you see them. But they're between 12,000 713,400

Nick Jikomes 7:03

years, I see, and is a little bit older. Is it thought that these are likely to be, this was, like the first culture, the first peoples, to actually get into the Americas? Or is that debated? Or what's going

James Chatters 7:15

on? Matter of debate.

Ben Potter 7:17

Yeah, it's complicated. I think we'll have time here to nuance it. So that's great, because the media sometimes, you know, latches onto a number or a site. So when, when Jim mentioned, this is the first widespread cultural manifestation. This is what we'd expect to see for a colonizing, very rapid spread of people in a very short window of time, as Jim mentioned, and the toolkits are very homogeneous. They look the same wherever we find them. And that really does speak of a colonizing population, roughly 13 five, some people argue is, you know, later, like maybe 13 113, 1100, but certainly a narrow window. So the question then is, do these represent the the first Native Americans that are the ancestors that are entering the region. And here we have to sort of look at the genetics as well as the archeology. And from what we can tell, there's, there's three major branches of Native American ancestry. The first two, or two of them don't matter as much because they're in the Far North. So ancient beringians are the ones that I normally deal with up here in Beringia. And they never really got further south, and say, the Yukon Territory. So they remained in Beringia, north of the ice sheets. The northern Native American group, nna is what they're called. That's a metapopulation that seemed to remain in the northwest coast. So basically Puget Sound north into sort of a British Columbia coast and Alaska coast and those people, we don't really find them further south. These would be ancestors of algonquians, Dene, people like athabascans and Tlingit sailuk, like that. Of course, at the very end of the record, we see, you know, a later movement south of Navajo and Apache ancestors. But we clearly know they're coming from the north. So that leaves the main plate, or the main meta population, which we term South Native Americans or SNA and that's basically the ancestors of every Native American, sort of south of Canada, so all the rest of North America, Mesoamerica, and all of South America. And when we look at the individuals that are that are linked with this genetic group, the Anzac individual is, of course, the earliest. It's the very first one we have. And every other ancient remain we have, Spirit Cave, la gua Santa people in further South America, they're all part of sub lineages of this SNA group. So really, we're looking at the peopling of this SNA group, and genetically, sort of the diversification within that is somewhere between 14 eight and 12 eight. So 14,000 812,800 which does map on really nicely to when we see this Clovis phenomenon. And so then there's two questions, you know, do these represent the earliest peoples? I think, as as Jim mentioned, the. The there's not firm consensus. A lot of folks, I think many of our colleagues, agree that this is probably the case, but there's probably a smattering of earlier materials that are probably the direct ancestors. Genetically, we know that these early SNA groups are very small, so maybe a single founding population of maybe 200 individuals. You're not going to see that archeologically right away. It takes some time before they build up. So some of these sites, perhaps Monte Verde, perhaps paid Latin, you know, if these are connected, associated directly with secure dates, those could represent, you know, clovid, Santos certainly. And we really only find them at enough numbers, at around this 13,000 year period. And and then there's the other argument for maybe really early sites, like, you know, White Sands, footprints, the coopers ferry site. There's, there's a few sites that are out there that have been argued to be older than 15 or 16,000 I think definitely the jury is out on all of those don't seem to tap on genetically with what we understand. And I think White Sands might prove to be the most secure at this point, maybe 22,000 and that's the time period when, when we know Native American ancestors are still admixed in with other groups in Asia. But we don't know who those people are, if, if the dates are secure. So it's a complicated question, but COVID is really important in this debate,

Nick Jikomes 11:19

but, I think bird's eye view here, if I'm if I'm understanding correctly, no matter what the specific answer to the question of who are the very, very first people to get into the Americas. At some point, there were these people that had a certain culture that's referred to the Clovis culture. And you start to see that everywhere in the, you know, from northern North America all the way down into South America over a relatively short period of time, which implies that there was some kind of, at some point, some kind of fast radiation outwards such that they all retain the same culture, because they presumably inherited that from from a common ancestor. And so the Clovis people sort of spread very quickly throughout the Americas, starting at some point, perhaps they were the first people, and there were more ephemeral populations of their ancestors. There a little bit here, a little bit there, before that, perhaps other people were around. Maybe there's some debate on that. But at some point, this Clovis culture kind of spreads very quickly,

James Chatters 12:14

right? We have a there are really only a couple of possibilities here, given the widespread distribution of Clovis, one is there was nobody else there to begin with, so they are the first. Or if there was somebody there already, they had a completely different ecological niche. So it was possible for this expanding mammoth hunting Clovis population to enter their landscape, their their regions, without competing with them, and therefore capable of moving in without any impediment. Those are really the only viable two population, two possibilities there, and the latter would, as Ben was pointing out, require that we had some previously existing genetic population that no longer exists.

Nick Jikomes 13:11

So, I mean, it's a formal possibility, but what we don't lack, we lack that kind of evidence that would definitively show Right, right?

James Chatters 13:19

The possible. Archeological manifestations that could predate Clovis, or what we recognize as Clovis, are not very much older than Clovis, and they, in the case of say, like the Wally's beach site in southern Alberta, where there are horse and camel kills, definitely human killed animals with artifacts left behind with the bones. We don't find spear points with those, but those might just be the earliest Clovis populations. So some of these other ones, Ben mentioned Monteverdi. I don't think Monteverdi is a possibility. It's way too far south to have been part of this. If it isn't the rapidly expanding population like Clovis, it's not going to make it South America that fast if it's part of that same genetic group, what we see in South America instead is we see a culture that is clearly Clovis derived, called the fishtail complex. The spear points are like Clovis points only. They have a waste and those appear in South America. And as soon when they start appearing, you can see their numbers increasing in frequency as the number of species as the now extinct species decline. It's just a complete opposite directions they're going. So it's pretty clear that people are coming in as Clovis derived populations, probably after around 13,000 years ago. Yeah.

Nick Jikomes 15:00

And so is the idea here that these people walked over from Asia over what is today the it would be the land bridge that connects present day Russia to Alaska, and they came in through that route.

Ben Potter 15:15

Yeah. So there's certainly debate as to routes, and our paper doesn't speak to either route. That doesn't really matter. The point is, at some point, whether they came through an ice Creek corridor or whether they came along the coast, eventually they got to the America south of the ice sheet, and that's where our story takes over and relevance to sort of the peopling part of this is that our our data now, for the first time, we have direct evidence of what they were, what their economy was like before. We just had indirect evidence. And we can talk about that. This fits into pretty elegant models for the the nature of this life, nature of this adaptation that allowed people, modern humans, to expand into these very far northern regions make it to Beringia across the land bridge. East, West is not a problem. It's the North that becomes an issue. How do you, you know, take mid latitude adapted peoples and then have them survive in the far north, which is much more difficult, and then they took this strategy, which included prop city and hunting through Alaska, and then we see them, you know, in this Clovis population. So it does allow us to begin to explore and explicate the nature of this adaptation, how they became so successful. Because this was a very successful adaptation, a very successful colonization event, which led to all of the Native Americans, the many millions that have had successful heritages, sort of just through through the millennia,

Nick Jikomes 16:41

and so remind us to in terms of the big timeline here is this time period that we're talking about? Is this still considered the Ice Age, or is this the tail end of the ice age? And how far? How far is the ice going across this period? This is, this

James Chatters 16:57

is the tail end of the Ice Age. The deglaciation begins about 16,000 years ago and increases in its in its speed of of melt, and the glaciers are pretty much gone throughout all but the northern parts of Canada, Northeastern Kuwait, and by around 12,000 years ago, majority ice is gone, so it's a fairly rapid melt off. And the argument has been there are two ice masses. One is the continental ice and the is the other is the Cordilleran ice. So one is coming off the Canadian Shield and the other off the western mountains. And as one moves east and the other West, they coalesce in what is now Alberta up into the Yukon. And the question is, When did those two ice masses separate enough that human populations could pass down between them, and those who suggest that people entered the Americas by way of the Pacific coast, for which, by the way, there is thus far no actual evidence that they either pass through the Pacific coast, because they don't think the ice between these two glaciers had separated enough for populations to move down between so when did the ice free corridor open up enough that people could enter which the big question, and Ben probably has a better handle on what the current thinking on that is, what the most Recent dates are on that,

Ben Potter 18:40

yeah, yeah. So that that's there's still debate. It hasn't been resolved. You know, the early estimates are something along the line to 15,000 this would be passable. And we have plants. We have sand dunes that are activated, certainly impossible if it's under ice or under per glacial lake. Others have argued that it's more restrictive. Maybe it's 12, 612, 1600, or so. So obviously, this is a really important debate, because Clovis, we see generating roughly around 13,000 a little bit before. I think most models would be fine with Clovis going through the ice free corridor, even the skeptics. But the issue is, what about these early sites? And you can see the issue. It depends on which early site you think is their association. Those that think that they're not that good, there's no problem. Those that think, wow, the 16,000 year old site is a legitimate then there's the issue of the quarter might not be passable yet. So it's all tied to the scattering of and I'll just have to say, very different sites with very different levels of evidence. None of them link with each other, and none of them link with later people. There's always going to be debate. They're not really, they're not unequivocal. And so that's, that's, ultimately, it doesn't matter for our purposes, because this is a successful, you know, and it took a successful. Expansion with Clovis clearly genetically linked with later peoples, with all later peoples. So it makes this, the research that we just published, important at a number of different levels. To look at this library, aeroglacial hunting of large mammals, like a fauna, very near ice. This is what we clearly see in in Siberia. We clearly see it in Beringia, and now we see it in Montana, or what was, you know, ancient Montana, almost 13,000 years ago. In fact, you can see it all the

James Chatters 20:31

way east into Europe, going back into the gravettian. I mean, it's, it goes back into the close to 30,000 or over 30,000 years ago that people had begun hunting in paraglition environments and killing them. So it's not a, not a recent phenomenon.

Nick Jikomes 20:48

Yeah, I was actually going to ask this. Ask this next. So you know, by the time you get Clovis and the paper that we're going to talk about, the predecessors of these people, the people that were already in Eurasia and other parts of the world. So it sounds like there's already evidence that they were engaged in hunting large animals and doing that type of thing in glacial or periclacial environments. Yeah, there's

Ben Potter 21:11

really exciting research. My I've been involved with a team up here at University of Alaska Fairbanks, led by Matt wooler, where we're really trying to look at a mammoth ecology, particularly stable isotope ecology and sort of mobility with the sort of strontium and oxygen and other kinds of elemental analysis. It's really interesting. So we published, just earlier this year on there was an earlier male mammoth in the later female mammoth, where we're taking sections along the tusk and looking at their life history. Where are they moving on the landscape? And some of the things that we found is that they're very, very mobile, managing to pretty much move across eastern Beringia, number one, number two. There are certain areas that they like. So there's certain habitat that seem mammoth, friendly. And really interestingly, those are the areas that we see the most occupation, these early pre Clovis occupations that are that are clearly in secure context, sites like one point dating the 14,000 or 14,000 years ago. We actually have three mammoths that were found at that site, including that's where this one female died. And so we're really getting a good picture of how people can adapt to these paraglition conditions, in what we term the Arctic step, or the mammoth step, where you have tundra like plant, you have step like plant into this very productive grassland ecosystem found in East northeast Asia, Siberia. It's found in Beringia, and it is found in the northern Great Plains, where we've worked on the tantric one individual. So this is an adaptation that is geared towards late glacial, relatively homogeneous sort of landscapes, prior to this onset of the policy and warming. So it's an interesting and very successful adaptation I see.

Nick Jikomes 22:57

So basically sounds like using isotopes, and maybe we'll get into some of the method, methodological, details a little later. But basically, there were mammoths all over the place. In certain parts of the world, they were mobile. They moved around a lot, maybe not unlike present day animals of different kinds. They probably migrated from one place to another according to what was going on from one season to the next. And it sounds like a lot of the evidence in sort of the pre Clovis world, you guys and other people find, you find ephemeral human encampments, meaning it looked like people were at places for certain parts of the year or for little bits of time, and it really what you were just saying. It sounds like they're following around animals that move around from one season to the

James Chatters 23:38

next. Right, the sites that we see that we see that are associated with that are Clovis, the campsites that are Clovis are retain very high patterning. Okay, people are there briefly. They're doing a few things within that space, and they're not occupying it long enough to change what they're doing within within any of the parts of that space. And so your record is very, very it's a very, very clean stamp of behavior. It's left behind so that that tells you the people were only there briefly and only once had they returned repeatedly to that same locality. You'd either see a sort of a will be referred to as a palimpsest of different occupation events breaking up the discrete patterning that you see from that first episode of occupation. You either see that or you'd have stratified sequences where you where you have the same kind of camp there repeatedly as sedimentary processes, cover up the previous camp. You're still seeing people coming back over and over again. Clovis. We don't see that in in western Clovis, particularly, we don't see that any camp we see was occupied once, once only, and never returned to again. And so what these fit is an idea that was put out by you. Bob Kelly and Larry Todd 40 years ago, and that is that Clovis people were moving from kill to kill. So the population would stay at the previous kill location, the non mobile members of society, the children, the caregiving women, the old people, would stay behind at the last kill and continue to live off what's left of it and maybe forage around the landscape a little bit while they're waiting for the able bodied folks out there hunting mammoth, then come back and say, okay, or more elk or bison, or whatever they were going after and come back and say, Okay, we've got another one. And so pick up and leave and go to that next spot, never come back. That's the pattern we see with Clovis. It fits. It the pattern that we've been seeing since they put out that idea has continued to reinforce that interpretation.

Ben Potter 25:59

We should talk about the implications of this. There's broader implications beyond just simply, that's interesting about the past. So when we study hunter gatherer human ecology, you know this is as a species. This is 99.9% of our time on the planet has been as members of small hunter gatherer groups. And in the recent past, we have ethnographic information we can actually visit and look at the history, you know, look at what they actually do on the landscape now, and we can, sort of, we can model the success of that behavior. But when we look at maybe foreigners or collectors, different kinds of models we have now, there's nothing in the in the recent past that matches the expectations that we see these early peoples. And so when and Kelly and Todd modeled this, when they thought about this way back when they invented a new type, a traveler, a new kind of human ecological model that doesn't really map anything that we've got today, obviously it had profound impacts on how we populated the planet. And so this is the importance of that particular model. It relied on megafauna specialization. It relied on mapping onto the animals. You understood their ecology. You could enter new areas. You could break biotic barriers. If you did something that would be akin to more modern foraging ecology. You're limited to a certain area. You're really, really good at getting everything you can you're mapping on to that place. You can't transfer that knowledge to a new place very easily, so it's a very different way of light that we're trying to uncover. Yeah, yes.

James Chatters 27:30

As animals expand their range, they typically do what's called Habitat tracking. They they move with the kind of habitat as their habitat expands as a consequence of climate change. In this case, the habitat is the animals themselves. So they're, they're they're following animals that they understand, moving into a new landscape they may not know with an ecosystem they're not familiar with, but the animal that they're seeking is still familiar to them, so they don't have a big learning curve as they move into that new ecosystem. So that's what allowed them to move across the continent into all sorts of different ecosystems, because they were found their their habitat itself

Nick Jikomes 28:15

was mobile. Yeah, yeah. The habitat is is the animals that they're following, yeah, their

James Chatters 28:20

niche was a mobile niche. I guess have niche is a better word to use, or in this case, for ecological purposes, it was moving, and they simply followed it.

Nick Jikomes 28:29

Yeah. And I suppose, if this is all true, and it sounds like it probably is, another implication is like, when you think about, for example, all of the Native American populations that we might talk about in history that ended up arising in North America. If what you're saying is true, Ben, what you mentioned, if they are descended from this type of person, it means that when we think about their diet, when we think about how they emerge and evolve, we actually can't look to other hunter gatherer populations that are more recent, you know, in other parts, in other parts of the world, as a, you know, as a as a map to to what might be as a map for, for how these people used to live and who they're descended from. This is sounds like a relatively new culture that arose that allowed people to eat mobile and follow around these types of animals. It

James Chatters 29:21

was kind of like an old culture.

Ben Potter 29:22

Yeah, it's complicated. So part of this deals with sort of modern humans. We're all talking about modern, anatomically modern humans, with just the same brains and same social complexity that we have today. So that is more like this is the ancient model that allowed for relatively small populations with very high mobility, large territory sizes. That was what was dominant in the past. The last I see what's interesting and what's, you know, sort of the big anthropological questions today are, how do we shift from that to, like, beginning to domesticate plants and animals? Yeah, that's really interesting. Same, because you need to know what happened before to understand the context of that very new kind of tradition. And we see this independently emerge in various places in the Americas. So it's very, very exciting to understand that baseline, that that that persisted for such a long time around the globe, and then these Holocene shifts, and it does tie into climate change. So when we look at sort of expectations of this global warming that we experience now, and by the way, it's much more pronounced in northern in the higher latitudes, they appear in the Arctic, and understanding the last major time that we saw a major warming event was this period we're talking about. And for timing, the expansion of Clovis and SNA groups occurred during the bowling ally red period. So this was a warmer interstate period within the Ice Age. And at the end of it, at the end of Clovis, we see a sharp turn to more colder, arid conditions called the Younger Dryas that your readers might or listeners might be familiar with. And at the end of Younger Dryas, that's that last gasp, and you get the expanding, warming, moisture conditions of the Holocene. So what's interesting is not just sort of this expansion in its warm period, but in the end of Clovis, basically, Clovis populations begin to adapt to more local conditions right at the onset of this Younger Dryas. So there's definitely a climate signal happening for the success of this group in ways that we're still trying to disentangle. Now,

James Chatters 31:28

yes, it's possible. It's coincidence, simple coincidence, that the mega fauna that human beings were dependent on were becoming so depleted that they needed to focus on more local ecosystem at the same time as the Younger Dryas occurred. These are these are coincident that the extinctions of mega fauna are occurring just before the onset of the Younger Dryas. That's where the dates tend to be coming. Coming out these days is not too much under not too much less than 13,000 years ago is when we see this kind of cliff of mega Fauci populations dropping off. So around 12,007 to 12,800 we we see the beginning of the the Younger Dryas and so. And at the beginning Younger Dryas, at the end of Clovis is when we start seeing the local populations develop their own ways of life. In the northeast, you have the caribou hunters. In the Great Plains, you have the bison hunters. But in the southeastern United States and in the late country of the West, you got people who are becoming more generalized hunter gatherers that are using a lot more plant materials and things like that. So each region has its own Clovis descendant population doing something that adapts to the local environment.

Nick Jikomes 32:52

And before we like get to this period, and again, we look back at the predecessors of the Clovis culture, how long do we think people were hunting mammoths and living these very mobile lives doing a lot of hunting? Is that, like, 10s of 1000s of years of human pre history that we're talking about?

Ben Potter 33:12

Yeah, so in the in the old world, you know, in Eurasia, there's lots of evidence of chromosidian hunting. It's not necessarily specialization like that's all that they did. But it was a wide suite of megafauna that clearly could be exploited by and were exploited by modern humans, and also Neanderthals. Mentioned them. This is a very, very, you know, very long term adaptation to mega Fauci hunting in northerly areas. And this, of course, is long before we've got evidence of domestication or use, widespread use of plants, that sort of thing, so broadly when we talk about, you know, a Paleolithic, you know, the old stone age, this is one of those adaptations that we're really speaking about, is this focus on what we what we would term, ecologically, the highest ranked animals on the landscape. In terms of your diet, you're going to choose the animals that give the most return for the energy that you're putting out. So this will be measured like in kilocalories, for instance. And when those animals are abundant enough, and your human population is low enough, carrying capacity is such that you can, you can basically, you know, those animals, effectively, that's the animals you should be choosing, and that's what we see. What's what we see evidence. So I can say for our paper as a segue, this wasn't necessarily surprising to us working on it, because we work on sites that have these animal remains in those sites, and mega Fauci predominate. But there are naysayers, you know, there are people that argue, well, maybe the big bones survive and small bones don't. So maybe it's just taphonomy, like maybe they were foragers, or they looked at modern ecosystems. Well, really, humans couldn't, couldn't live in the Great Basin, for instance, and just just live on Mega Fauci they must have been incorporating lots of smaller game, fish, birds, you know, small mammals, things. Like that. So there the the arguments were always secondary, right? We had indirect even arguments about, you know, spare points couldn't possibly penetrate, you know, a mammoth hide, of course, you know, relying on wooly mammoth, as opposed to Columbia mammoth, which were more likely the target. And then other researchers a year later, saying, Here's tons of ballistic evidence. And, you know, other kinds of data that showed that that, in fact, was an effective weapon against privacy. And you had this sort of debate, but from my perspective, it's the multiple lines of evidence that are the strongest. And we had multiple lines of evidence pointing to this, but we didn't have that direct data, and this is what our article provided.

Nick Jikomes 35:40

So it sounds like, you know, at a high level, at least, there's probably 10s, if not hundreds of 1000s of years of human evolutionary history, especially at more northern latitudes, where human beings were doing a lot of harvesting of ecologically high ranked animals. So you know, large animals are probably competing with or even, potentially even stealing from Apex, apex predators and eating a lot of animal products, especially at those more northern latitudes right

James Chatters 36:10

there's, there's

Ben Potter 36:11

some, there's some debate in Beringia, and that's there that I work in

Nick Jikomes 36:16

and remind us what, what, exactly, what area is that? Precisely? Yeah,

Ben Potter 36:19

Beringia. Beringia encompasses that area right now, includes Alaska. It includes Yukon Territory, basically the areas not covered by glaciers. Further south. It includes the Bering Strait, which is now underwater, and also the easternmost point of Russia, so Chukotka, Kamchatka, that region and broadly between the vertical again, mountains the POLYMATH River in Asia, and in the McKinsey River in North America. That's Beringia. So it's effectively its own subcontinent. The land bridge. People say, you know, it's a kind of a bad term. You think you might fall off the bridge. It's actually 1000 miles north and south. It's a land mass that connects our part of the world with Asia, Alaska, and so like with Swan point, for instance, where we have three individuals of mam, including baby mammoth ribs, which clearly are not caverns. They're hunted and brought to the site. We also have waterfowl. We also have evidence of other kinds of resources that were being employed in the Far North. A recent paper, we've identified Sam and fishing happening around 13,000 basically Lotus times. So Bridge is a little bit different. You know, they're certainly utilizing a wide range, along with the the mega fauna. The question is always, to what extent you can say a lot, yeah, that's not effective. We would like percentages. And that's one of the things that that Jim and I and our team, you know, brought out of this particular papers, we can put numbers on things, yeah,

Nick Jikomes 37:46

yeah. So I guess what you're implying there is, you know, there's, there's been a lot of debate over the years in terms of, okay, well, just so, I mean, chimpanzees will hunt and kill things when they can find them. The question is, how often can they do this? So obviously, people were eating meat to some extent. They were probably eating berries whenever they could find them, to some extent, etc, etc, etc. The questions have really been like, Okay, were these earlier humans? Were they essentially hyper carnivores that were specializing in meat eating? Were they still largely omnivorous, even if they were eating quite a bit of meat, you know, and so on and so forth? That's that's sort of some of the context here. A

James Chatters 38:16

lot of it has to do with the habitat you're living in, in the people who are living in the tropics, where there's a lot of fruit available, even as Homo sapiens are likely taking advantage of that abundance. When you move up into the mammoth steppe, which stretched from Europe all the way to the northern Great Plains in North America, you don't have a lot of plant materials that are edible for you, right? Unless you're going to be trying to exploit tiny little grass seeds, which makes very, very little sense for a mobile population to be trying to do. Your main food supply is going and the majority of the biomass that is edible for you at any one time is going to be mega Fauci. If you're not explaining the mega fauna, you're not going to be eating very much.

Nick Jikomes 39:07

Yeah, yeah. I mean, this is, I mean, it seems pretty common sensical to me. I mean that. I think what you were saying earlier speaks to that you're just saying, if you if the further north you go, if you just look at where the calories are located in the environment, you're gonna have a really hard time efficiently extracting those calories from your environment unless you are doing quite a bit of hunting of mega fauna. As you as you go further north, right?

James Chatters 39:28

We don't, we don't eat sagebrush, and we don't eat grass, and that's mostly what was in there. And we don't eat wet birch and baby spruces and things like that, which is makes up the rest of the steps. So if you're not focused on that fauna, then you're not going to be having much

Ben Potter 39:48

food supply when it's hard to interrupt. One of the elements that make the story so compelling, I think, to a number of media and the public in general, is there's lots of other elements that this ties into. You about method just, how do we do archeology? How can we tell what ancient people what their economies were like? And for instance, there's a debate that was just published last year about Association, like, how, what's the relationship between kill sites we'd expect to see relative to exploitation of animals and their abundance on the environment. And there were two sides that really argued from the same data, different conclusions. There's not enough kill sites to show mega funnel specialization. Oh, there are enough kill sites, even more than we expect to see, to show this association of mega Fauci so this tells you that that we're an evolving field, that you know this data can really provide evidence that can be helpful for archeologists everywhere to be thinking about the strengths and weaknesses of each kind of evidence and each type of evidence, and that we should be careful with our models and a little bit more sort of tied to empirical reality when we can

Nick Jikomes 40:58

so if we get into the recent paper, so the title of it, which people can look up, I'll link to it and everything. It's mammoth, featured heavily in western Clovis diet. So the punch line is right there in the title. Let's, let's really unpack this for people. So when we talk about the Western Clovis diet before this paper came out, what was the, what was sort of the thinking, or the debate of what could be true in terms of what these people were eating? Well, the argument

James Chatters 41:23

was between, were closed people, mega Fauci specialists? Were they hunting specialists, or were they generalized foragers, meaning eating whatever's in the landscape and not, not being mammal focused. And it's been a rather, rather hot debate going on, and people will point to the fact that, well, there are half a dozen rabbits in this site, along with a mammoth, and therefore people were eating more rabbits than they were mammoth. It's gone to that level and not taking into account the fact that a mammoth is a whole lot bigger than a bunny. But

Nick Jikomes 42:08

I suppose there's, I suppose there's that argument.

James Chatters 42:10

Well, part of the argument had to do with were the earliest peoples into the Americas likely to have a major impact on populations of mega fauna? Were they, in part responsible, or largely responsible for the extinction of those megafauna so rapidly at the end of the Pleistocene? And there's

Ben Potter 42:30

a lot of conflation that way. There's a lot of conflation too, between the question of work Globus mega Fauci specialists, and were they responsible for the overkill of 30 plus genera of taxa. Of course, those are different questions, right? So some might point to, hey, here's 12 taxes that never appear in Clovis records. So therefore it's nothing but climate change. Humans have no role. So a lot of the debate really were different kinds of questions at different scales, but it is instructive to think about the debate. They use the same data so often, you'll see the same tables of these materials arguing for fundamentally different conclusions. It's quite entertaining to sort of from the brinjen record looking south and examining this debate. Yeah. I mean,

Nick Jikomes 43:18

it's inherently harder for people like you guys, because you're studying deep history, and, you know, right, the records are very sparse. There's only so many bones you can find. And we're talking about stuff that happened a long, long time ago. I think it's worth mentioning, even to listeners, that you know this type of phenomenon happens in modern day bench science. You have the same exact data set, and you get, you know, these people from these lab say one thing, these people from this other lab say the other lab say the other thing, they're looking at the exact same data set. So oftentimes it's easy to overlook, especially when we pick up on topics that get picked up by the media. You know, you can have, you can have two different people looking at the same exact data set, and they're both experts, and they come to completely different conclusion conclusions.

James Chatters 43:57

What we did in this case was, there is in the archeological record of of North America, only one individual directly associated with Clovis artifacts. And so we had only one person who was demonstrably Clovis. We have two others that are in the same age range, but no artifacts associated, and so we can't say whether or not Clovis is there was their cultural identity. That one individual was a 18 month old child found in Wilson, Montana, known as the Anzick boy, and he had died around 12,800 years ago, based on direct radio carbon dating of his bones. And at the time they ran the radiocarbon dates, the folks at Oxford also published a whole table of the stable isotope measurements that had been taken from the same bone protein that the date came from. But in a. Decade, nothing had been done with that. And so two of our colleagues, Julie and and Stu said, hey, maybe we could do a dietary analysis of this. And they they came to to me and to Ben about that. And Ben had recently done a been involved in a study on that from the upward Sun river children that he had excavated up there in Alaska. So we took that and went to find the animals of the ecosystem and get enough data on stable isotope composition of the proteins in those animals to be able to conduct the analysis. Now, the sort of the core of this is two of the major elements that are found in proteins, carbon and nitrogen, have two stable isotopes. Each carbon has carbon 13 and 12. Nitrogen has carbon or nitrogen 15 and nitrogen 14. And in growing plants and in ecosystems, the plants have different groupings of plants have different proportions of these two isotopes in their tissues, and when animals eat those, they incorporate those differences and modify them slightly per trophic level. So there's a decrease or an increase in the concentration of nitrogen 15 and carbon 13 with each trophic step. So as you go from first order consumers, the plant eaters, you get a single trophic shift. You go the second order consumers, the the eaters of the plant eaters, and you get another trophic step because of the differences in both their their ecological niches and their digestive systems. Yeah, these different animals have end up with different proportions of carbon and nitrogen isotopes in their tissues, and we can take the pattern that we see among different species of animals, compare that to an individual or a species in question, and try and find out what its most likely diet was among the possible sources. Okay,

Nick Jikomes 47:27

so, so if we imagine ourselves back in this time period, just like today, there's all sorts of different animals. They occupy different ecological niches. Some of them are plant eaters. Some of them eat the plant eaters. Some of them might even eat the things that eat, the plant eaters and so on and so forth, depending on what an animal is eating, depending on how it's living in the environment, based on how it is, you know what it's consuming and how its digestive system is, is adapted to extract the nutrients from those food types. You get a different signature of isotopes of different kinds in those individuals. And so when you guys dig up and find remains from humans, mammoths, all sorts of other creatures. You can look at the pattern of isotopes present in that individual, and that will have a correspondence in terms of what that animal was eating. Was it a hyper carnivore? Was it an omnivore? Was it a plant eater, and so forth? Yes,

James Chatters 48:16

yeah, we could find out which of the animals in the ecosystem was the most were the most likely in its diet, in in their relative proportions. But there's

Ben Potter 48:26

a couple, a couple of ways we did this, and it's, it's really intuitive, if you, if you see an x, y graph for this kind of research, you'll see carbon on the bottom, and see nitrogen on the side, and you're looking at dots. You're looking at at points that represent individual animals that have been sampled for these for these variables, and the cluster, which is what we want like to see, the horse are all clustering down here with really low nitrogen. Mammoth have much higher nitrogen. They're really separate. So imagine these different cluster combinations on the map, and then you plug your here's your individual, in this case, the diet of cancer one's mother. We're looking at maternal diet. Get into it a little bit, and it actually very intuitively in two dimensional space. The closer the.is to these other animals, the more likely they're incorporated into that tissue. The second way we looked at this is through Bayesian modeling, where you're actually running statistical analyzes to actually get a proportion of mean and a standard deviation around what proportion of diet is being contributed by this taxon versus the other taxon. That's where we got the 35 to 40% of the protein diet is coming from Mammoth, specifically, higher than any of the other any of the other mega fauna, and also that small mammals collectively only contributed 4% or less of the overall diet, and it's a court stands in stark contrast to this model of Clovis as generalized forager. The third way we did this was we looked at the secondary consumer, so the carnivores and omnivores. Here, we're looking at where does the overall tissue of. The Maternal, you know, the insect one's mother. How does she lay out relative to these other animals that we understand their ecology? And interestingly, she was closest to homotherium, which is scimitar cat, was at Saber Tooth cat variety that we know was a juvenile mammoth specialist. So there's an independent line that says she's more like that than, say, a bear, yeah, or a wolf, which is, you know, more omnivorous and then, you know, using smaller prey.

Nick Jikomes 50:30

Okay, so, so basically, to summarize all that, you can use radio isotope methodologies. You're looking at carbon and nitrogen isotope, not radio stabilized stoves. Okay, so you're looking at stable isotopes of carbon and nitrogen, and these things have a systematic relationship to an animal's ecology, what it's eating and the type of life it lives. You have samples from the past in this general place, in this general time, including this one human sample that will that we'll dig into, but a bunch of other animals, Saber Tooth, tigers, mammoths, small animals, a bunch of stuff. And you can sort of plot this stable isotope data out, and you get nice, clean clustering, or there's an orderly relationship between where the what the animal is eating, the type of life it led, and where it falls on this map. And so