Dr. David Gwynn

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906 appearances 4 recordings 1 series first heard Nov 2024 last heard 21 Dec

Dr. David Gwynn’s voice in public audio — every appearance, attributed to the second.

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Recordings per month over the last 12 months — 1 in all, peaking in Dec 2025 with 1.

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The Ancients · Ice Age America · 21 Nov 2024 podcast

You've got to learn about the geography. You've got to do wayfinding. How do you move out across that landscape and make your way back? you've got to figure out the climate and the weather. And there's a distinction between the two, of course, right? Weather is what you see outside. It's what's going to come tomorrow, what may be here next week. Climate are those larger trends.

And so if you are somewhere in the Northern Plains and it's fall of the year, and you don't know that winters can be pretty darn harsh in that environment, this could not work out well for you, right? So there's going to be a strong incentive to learn as much as possible, as quickly as possible, about as large an area as possible as you can.

On the other hand, there has to be a compromise because if you're just running willy-nilly around this entirely new landscape, you're not going to learn enough about what's going on in places with particular resources, right? You need to figure out, well, how do the animals in this locale, how do the animals on this landscape, in this kind of environmental setting, how do they behave?

How do they behave at different seasons? How do they behave when there's young? How do they behave when there's other predators around? Because you've got to figure out enough to be a successful hunter-gatherer. So there's this sort of tension there.

between wanting to go as far as you can, as fast as you can, to learn as much as you can, and pulling in the opposite direction, the need to stay and observe, stay and experiment, right? You've got plants in front of you. They have really lovely little red berries. Do you eat them? Well, no, actually you give them to your younger brother and make him eat them.

And then if he gets violently ill, you know, this is not a good thing. The whole process of adapting to a new landscape Finding your way around, finding your way back, learning about it is really fascinating. And that's one of the really interesting things that has great potential in terms of the DNA.

Because one of the things that we would suspect is that when groups come into a new environment, they're going to disperse. Because more eyes in more different places, then you come back from time to time, you get together, you share information. Okay, you don't need to go in that direction. We've been there. It doesn't work.

Or we've been there and this is where you need to refurbish your stone tools. There's a wonderful geological outcrop there. This is how you deal with the animals that you're going to find there.

With ancient DNA, we can potentially identify those sort of rendezvous moments where different populations that have perhaps been separated by decades or centuries as their ancestors dispersed across the landscape, can we see them coming back together? We do know that dispersal process was in fact very, very rapid. The genomic signatures that we have in 10,000 to 12,000 years ago.

Time period in North America are very, very similar to the ones of ancient individuals in places like Southeast Brazil 10,000 years ago.

I would actually use the word stunning rather than surprising. We'd always suspected archaeologically because of the near-contemporaneity of radiocarbon dates north and south in the hemisphere.

But now we have genomic evidence that seems to, in fact, affirm that where it looks like, you know, the difference in sort of the genealogies, as it were, the genetic genealogies of these populations is that we're just talking about a limited number of generations before descendants of these groups that are in North America are already in South America.

We actually call it a quick wave where, you know, small groups are just scattering and And then one of the other things that we found, and I can't remember if we talked about this or not, but it's just such a cool finding. I have to repeat it.

If we didn't, they took their dogs with them. One of the studies that we did, and this is work with my friend and colleague Gregor Larson at Oxford. Gregor's a specialist on ancient dog DNA, and he had a student and colleague, Angela Perry, also a specialist in dogs.

Yeah, fantastic episode. Oh, fantastic. Yeah, yeah, yeah. So I was talking with Gregor and Angela one day about their dates on dog dispersal based on dog DNA. Okay. And as I was listening to them, I was thinking, hmm, those sound a lot like the human dates that we have. And then it dawned on me, I can be really slow about this sort of thing.

It dawned on me, dogs are not going to colonize or move into the Americas by themselves. right? They must have come with people. So as people are moving through the hemisphere and splitting off and radiating out, of course, their dogs are going to have a similar kind of pattern because the dogs are going with people. People can go without dogs, but dogs don't go without people.

And so we published this paper and it was just a lot of fun to work on, to be sure, because we had these two very independent sets of evidence, which very nicely tracked one another for obvious reasons.

Well, formidable ones would be the answer. You have everything from Brachyprotoma obtusata, which is the short-faced skunk. And there will be a quiz afterwards on the genus and species names for all of your listeners. There was the spectacled bear. There was the giant short-faced bear. There was a saber-toothed cat. There was a scimitar cat. There was an American cheetah.

These are all distinct genera. And then there were species such as the dire wolf and the American lion, Panthera leo. And I have to give one more scientific name for the saber-toothed cat just because it's so cool. The saber-toothed cat's name was Smilodon fatalis, which is kind of a mashup of Greek and Latin. which basically means roughly deadly knife-toothed.

I mean, you had these sabers that were some six inches, these two fangs, basically, canines. Six inches? Six to eight inches long. They were probably about a quarter of an inch wide. They were serrated front to back. This was an animal that would rip your throat with one chop.

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