Human evolution questions that keep me up at night

Did Neanderthals or some other archaic human make it to North America? That's the first thing we're talking about today in just human evolution archaeological questions I can't get out of my brain. This is literally that meme where that woman's wondering what her partner's thinking about. This is what I'm thinking about in that scenario. Did Neanderthals or someone make it to North America? It's an interesting one. By the way, this is all coming completely off the top of my head today. I just feel like free-flowing, freestyling, as it were. This is a question I've changed my mind on a lot. Usually when people talk about this, they're talking about the Cerruti Mastodon, which was a mastodon that ended up underneath a California highway in some bizarre scenarios. Strange things have happened to it. The bones were broken, the tusk is upside down in the ground, and yet it seemingly was deposited in quite calm environment, like a stream or something gentle that covered the bones. Not the usual environment where this amount of damage can be done to a mammoth, so it's been argued that this is evidence for human activity. Problem is, there's no modified stone tools, there's no cut marks on the bones. Strange things are happening, like some of the teeth have been bashed in, and humans don't really do that so commonly, like hitting a mastodon's tooth so hard it shatters. That's a pretty hard thing to do. And it was uncovered by a huge piece of commercial digging equipment. A digger. It was dug up by a digger. One big enough to build a motorway. So, it's an odd one. I'll freely admit it's an odd one, but on its own, it's not enough to prove that some form of archaic human was in North America. But, but, but, but, but, but, there's another site I want to talk about called Deering Uriak. This one is on the other side of the Pacific. This place is about 140 kilometers southwest of Yakutsk in Siberia. This is the coldest large city in the entire world, allegedly. They've recorded temperatures up to minus 64.4 degrees Celsius. That's minus 83 Fahrenheit for my American viewers. What can you say about that? That's bloody chilly. Shout out to everyone in Yakutsk. Rather you than me, but I'm sure it's lovely. Here at this site, Deering Uriak, archaeologists found what are lower Paleolithic stone tools. These are your kind of stone tools that a Homo erectus or something was making. Like simple bifaces, choppers, things like that. These stone tools, whenever I show them on screen, they just literally look like rocks. And it is hard to identify these stone tools sometimes, but it's all about how many flakes were removed. Are they removed in a pattern? Are there multiple stone tools where flakes are removed in a pattern? That's the kind of thing that archaeologists are looking for. Obviously, when you go back far in time, stone tools are simple, man. Our technology was simple. We're really just bashing rocks together to get something sharp to cut up an animal. There's some debate about the age of this Deering Uriak site. It just seems like they're having a hard time untangling the dating there. Some have argued it's 260,000 years old. Others more in line with 400,000 years old. It's pretty old. Pretty, pretty old. And it would have to be pretty old for them to be making those kind of simple stone tools as well. What's not up for debate, though, is just how far north this place is. It's really, really far north up there in Siberia. This, as far as I'm aware, is the furthest north lower Paleolithic site in the entire world, and which on its own says a lot about human adaptations, right? Can hominins have been living that far north without some form of clothing, shelter? It's not likely, right? It's not likely. Maybe they were just there in the summer before legging it back down to warmer climates, but you can't help but think they're building shelters. They've got clothes. Not clothes that are sewn, but, you know, meat ponchos. They're rocking some furry ponchos, at least. Had to be. So that's cool. That's very interesting. But I didn't fully appreciate until I pulled it up how far north it was in relation to America. So it's about 61 degrees north, which basically is as far north as, like, half of Alaska. A lot of Alaska. I don't know why when I see it on a map, I just didn't fully appreciate this. Hominins were living as far north as basically the entire western coast of Alaska. When I'd seen these maps, I always just assumed people were way further south, sort of level with North Korea, that sort of region. Much further south, which would put them in line with North Korea. Fortieth degree. What? North Korea is level with, like, northern California? I did not appreciate that either. What? Climates are weird, man. How is California the same latitude as North Korea? Climates are weird, man. Climates are weird. 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So that's point number one I didn't appreciate in this whole debate. The second thing I did not appreciate is just how long Beringia was around. So Beringia is this landmass that connected Asia to North America. When times are cold, sea levels are lower, all this water is trapped, there's ice, this land bridge forms between Russia and Alaska. How far is it even in this day and age? Even today, there's only 82 kilometers between them. What's that in miles? I'm getting confused. That's 50 miles. Yeah, 51.5 miles. So there's only 50 miles between Russia and Alaska anyway. So when sea levels are lower, much lower, these places are connected. You know, so easy to do this. I had kind of assumed that how the world is now is more or less how it was in prehistory. And when this land bridge existed, that's the exception, right? Because you kind of have this bias that how the world is now is how the world was. But at least according to the National Park Service of the United States of America, Beringia existed for perhaps 80% of the last million years. Like how we are now is the exception. Most of the time, Beringia existed. And that's just something I did not appreciate. Like I said, it's so easy to have this bias that how it is now is how it was then. But that's not true. So considering archaic humans were as far north as 61 degrees, 61 degrees north, and considering the fact that Beringia existed perhaps 80% of the last million years, I think hominins might have made it to Alaska. They really had a long time to get there, and they were clearly capable of living in that kind of climate. How far away is Deering-Uriak from Alaska? Okay, so it's 2,000 miles from Deering-Uriak to Alaska, which isn't close, right? That is not close. 3,300 kilometers. But humans tend to expand. That's what we do. Why couldn't they have made it to Alaska when they're that far north? Now, did they make it below the ice? I don't think so. The sea levels are lower. These huge glaciers form. Basically, all of Canada, Oregon, Washington is under ice. I don't think they made it below that ice. I think that ice was a real barrier, a real, real barrier to the expansion of humans and animals. When that ice was there, humans are not getting through that, at least until later on when we had properly developed boats and things, like how the ancestors of Native Americans got here. So I don't think Homo erectus, Denisovans, Neanderthals, I don't think they're doing that. I don't think they're capable of an Arctic sea voyage. I don't think we have evidence to say that. But did a Denisovan make it to Alaska? I think so. There's no reason to think they couldn't. I don't know how the climate is over there. Well, it's cold. What are the chances of finding these lower Paleolithic sites, middle Paleolithic sites in Alaska? How easy is that? I'm not sure. I think it's, they might have been there, man. They might have been there. I can't stop thinking about prehistoric religion and the origins of human religion. Isn't it kind of interesting that we have this sort of symbolic layer to everything we do in the world? Every culture has a religion of some form. And even if you are not personally religious, like me myself, I just don't really think there's an all-powerful being watching over me, dictating all the different aspects of my life. I just don't feel like that's the case. And yet, I am also basically unable to avoid religion because religion, and I'm sort of tying in symbolism here, it's just this whole layer we add on to the world. They're trying to make us use, you know how Facebook is trying to get us to wear glasses with augmented reality? Our religion, our symbolism is kind of like, we're doing that already. We're already augmenting reality with these stories, with these ideas, with these practices. It's very, very interesting. I can't help but wonder where it comes from. And especially when I see things like this. This, believe it or not, guys, is a picture from Chauvet Cave. You know the one in France. It's so famous for all the incredible artwork. But there's a chamber there where a bear skull was placed prominently on this rock. This is a bear skull here. You can see another one on the floor beneath it. I can't remember how many remains of bears were found in this cave, but it's a lot, right? It's really a lot. There is no way that the placement of that bear skull is accidental. There's no way. That's exactly the kind of thing humans do, right? We find this odd thing in nature and we construct a story around it. We construct a narrative around it. It becomes part of this augmented reality. And this wasn't put back on there by the archaeologists. This is basically how someone left it 25,000 years ago. 25,000 years ago. Imagine all the things that have happened. You know, if this was a film there, it'd be that montage of day turning to night, day turning to night, day turning to night, whilst all of human history transpires. And this bear remained on that altar. I'm going to call it an altar. It could have been just a guy messing around, right? It could have been just a guy messing around. But humans love to add this extra layer of symbolism. And I've just been thinking a lot about how much of our religion is a combination of unusual natural phenomenon and us sort of unable to explain the feelings that we feel in our body. Like, for example, when you're in a cave, it's dark, it's a different atmosphere. Your senses are kind of going crazy. It's not a comfortable place. And there's something that humans love about that. We love that uncomfortable feeling. And we kind of seek it out. And we'd love to wonder about it. As again, I could keep saying, saying stories, but create stories around it. You can't help but feel these people are in this cave, feeling these things that maybe, if they're not hunting bears, they're coming across the remains of lots of them. And then there's this prominent rock in the center of the chamber. They place one there. What sort of rituals and everything have been forgotten to time by this cave? I don't know. It's so incredible. I've just been thinking a lot about it, especially because I learned that there's this really interesting rock. This is the most beautiful rock anyone's ever seen. And I can prove that to you. This is a conical stone, black stone. This is apparently the idol that was at the center of the main sort of temple of Aphrodite. Is this in Cyprus? Yeah, in Cyprus. At Aphrodite's sort of main shrine, the island where she's believed to come from. Are people worshipping a statue of this incredibly beautiful woman? No, they're worshipping an unusually black rock. And how long had people been investing this rock in meaning before it got to classical Greece? Who knows? Maybe countless thousands of years. And it's just, I just can't get this out of my head. How much of this sort of augmented reality that we build around us that is important. I don't mean to be dismissive about it. It's extremely important for human life. It's probably essential to human life. Maybe it is literally what it means to be human is to have this extra layer of reality on top of the earth. And how much of that is just our ancestors being in strange places, feeling strange emotions, and stumbling across unusual natural phenomenon? That thought keeps me up at night, man. That thought keeps me up at night. How much of the things that I do and believe in my day-to-day life are because someone 10,000 years ago found a black rock, you know? That's interesting to ponder. Okay, I'm lying in bed at night. I cannot sleep. My thoughts are whirring. My family asleep around me, snoring away. What am I thinking about? When did the last archaic human die out? When was the last Neanderthal alive? When was the last Denisovan alive? Any other groups, homo floresiensis? When was the last one of them alive on the earth? Now, caveat, caveat, caveat. Of course, they interbred with us. So in a sense, you know, some people would argue they are alive. I don't know. We're only like 2% Neanderthal, right? So if they are alive, it's not much of them. But if you want to think like that, it's not inaccurate. But still, when was like a real Neanderthal alive? A Neanderthal community not admixed with us alive. A Denisovan community alive. It's so hard to say, right? It seems that Neanderthals are gone by 40,000 years ago. There isn't anything securely Neanderthal dated after that, really. By 40,000 years ago, homo sapiens have spread out all across Europe, Asia, up into the Arctic, Australia. We're basically everywhere by 40,000 years ago. If there's anyone alive at that time, there's not much room for them, right? We're going to be finding small pockets of humans. But small pockets of humans is basically how life was for most of the Paleolithic. So could they have survived somewhere? And I think our best chance of finding a late survivor are Denisovans. First of all, the admixture between the homo sapiens and Denisovans is believed to have happened later because it happened after Neanderthal inbreeding. So interbreeding with Denisovans must have happened sort of roughly 40,000 years ago, maybe a bit younger. And what's interesting is that we have interbred with Denisovans multiple times. There was a DNA study that came out on this six years ago now. Multiple deeply divergent Denisovan ancestries in Papuans. Papuan populations have a larger than average chunk of Denisovan DNA, it seems. And this is a result of admixture with multiple Denisovan groups. And one of the conclusions was with that study was that one of this admixing events with these Denisovan groups happened between 30 and perhaps as recently as 14.5,000 years ago. 14.5,000 years ago. Like, what's that? 30,000 years basically after Neanderthals went extinct. There's been a lot of debate around that number. A lot of debate because here's the caveat, right? Let's say you had two human groups that admixed with two different Denisovan groups and then later those modern human groups 14,500 years ago admixed together. It would look like the population perhaps had this new input of Denisovan DNA, which is true. They did have this input of Denisovan DNA but not because they admixed with Denisovans. It's just the two human groups who are now together had admixed with different Denisovan groups way in the past. So I've seen that as the caveat, as the criticism. I'm not a geneticist. So any geneticists in the comments, please wade in and tell me, is that right? Is that wrong? But that study does raise an interesting point. If 30,000 years ago, 25,000 years ago, were there still Denisovans somewhere in Ireland, Southeast Asia? It's very possible. And even were they in what was the landmass Sahel, Papua New Guinea, Australia? We don't have any archaic human remains or artifacts or sites that is definitive evidence of that. But it's not impossible. It could be that a population, a small population of Denisovans was alive in that region for tens of thousands of years after they had died out elsewhere. How likely is that? How much, if I had to put a number, if I was a gambling man, what would I bet on that? That's tricky. I don't know what percentage I'd put that as. I don't know how likely it is, but it's certainly a possibility. There's even over in Europe, some people have argued that there was a Neanderthal human hybrid called Lago Velho child from Portugal, who is Homo sapiens Neanderthal hybrid, who lived about 25,000 years ago. Now people have debated the bones and whether they truly show signs of Neanderthal admixture. But when that child was discovered, it wasn't known through DNA that humans and Neanderthals had admixed, I believe. I'm pretty sure that predates that discovery. And now we know that they did, and we have specimens like Oase from Romania, where they had a Neanderthal ancestor only like six to 10 generations ago. And it seems that Neanderthals were living out in Iberia longer than elsewhere in Europe. Could they have survived there? Perhaps. Going far north, if you watch my video about how far north did Neanderthals get, because of all the glaciations that have happened since that time, we don't have a good idea of the northern limit of Neanderthal boundaries. How far north did Neanderthals get and how long did they survive in those regions? Not known, I think. I think it's fair to say we don't have the ability to answer that question. So yeah, it's an interesting one. When did the last archaic humans die out? And did they survive perhaps tens of thousands of years longer than we currently have evidence for? Interesting one. That's keeping me up at night, guys. If you catch me at 3 a.m. having a bowl of shredded wheat, it's because I'm thinking about that. Okay, I'm still awake, guys. It's 5 a.m. now. I'm still awake. I'm on my second bowl of shredded wheat. It's getting to the point where you're thinking, I'm not going to go back to bed. I'm just going to ride out the day again because I've been thinking so much about this question. I've come to think of this as the biggest gap in the Paleolithic archaeological record. Is that true? I don't know. Feel free to discard all of my opinions, but it is a big gap. It is a big gap. So on screen right now, what you are looking at is the distribution of Acheulean tools. These are those like lower Paleolithic tools that we talked about with Deering Uriac, hand axes, bifaces, choppers, flakes, all of these things. As you can see, there are some big gaps in Africa. There's gaps in the Sahara. There's gaps in the Congo. But other than those two gaps, these tools are found across Western Africa, Senegal, Ghana, Nigeria. All of these regions, these tools are found. Angola, Namibia, all across the West Coast of Africa. Apart from those two gaps, these tools are found. And even those gaps, I suspect, exist because these are politically unstable regions, sadly, and extremely poor regions. Extremely poor regions where just less archaeological research is being done. I would bet those gaps of the Congo and the Sahara are not really reflective of the distribution of ancient hominins. They're just reflective of modern day archaeological research. I would bet. That's my hunch. But tools still, tools found across Western Africa. Now, let's go look at the map of early human remains where humans are actually found, not stone tools. I can't get a nice map, but it's all on the South and the East. Basically, exclusively, apart from a couple of sites in Morocco, it's all in the South and East. So there's basically this huge, huge hole in the core region of human evolution where we have no human remains at all, yet we are sure because of tools that humans were there. We're sure humans were in West Africa. We have the tools. The tools date to very, very old, millions of years old, but no human remains. That's a colossal gap. I can't stop thinking about. I mentioned this. I did a live stream with Flint Dibble. I mentioned this on his live stream, too. It's a massive gap in the archaeological record. And you can't help but wonder how many of our ideas are prejudiced or influenced by the fact that we have this incomplete data set, which is always the way in archaeology. But this just seems a particularly glaring gap in the archaeological record. You know, there are many questions we have about the evolution of hominins and early humans, like the transition from Australopithecus to early Homo, or the evolution of larger-brained hominins like Homo erectus, or we have this muddle in the middle where in this middle Pleistocene, the middle Paleolithic, who is the ancestor of humans and Neanderthals? We're not sure. We're not sure where they lived. And again, is that because in the core region of human evolution, we're basically missing human remains from two-thirds of the continent? That's really fascinating. And, you know, you could perhaps think about it like, ah, probably there's not much remaining there. Probably if we found something, it's gonna be more in line with basically what we found across Africa and Eurasia. And for the most part, that's likely to be true, right? It's likely that there are similar hominins living all across Africa at a similar time. However, however, however, however, we can't forget about Homo naledi. Before the discovery of Homo naledi, it was not believed the small brain hominins existed, you know, 200,000 years ago, 300,000 years ago. It was thought that all of those had either died out or evolved into larger brain hominins way before that, you know, million plus years ago. And yet we know that in South Africa, there was this island of hominins who were very different, very, very different until two, 300,000 years ago. And some of these areas, you know, to use Atlas Pro's term, could really be like islands that aren't islands. Maybe there's some Homo naledi-like hominin in these remote regions of Western Africa, in the Congo, in the Sahara, you know, Nigeria, Senegal. Who was living there? We have the tools. Who was living there? Are there incredible things to be discovered there? And when we're thinking about archaic humans and the evolution into Homo sapiens, were there any in Western Africa? How long did they live for? Did they contribute to the evolution of modern humans? It's entirely possible. There is that study where it talks about ghost populations in Sub-Saharan Africa. I think there's been a lot more, I don't want to really talk about that. I know probably in the comments, you're thinking about that. I don't really want to touch on that because I just have this thing in my head I feel like new data has sort of changed geneticists' thinking on that. That these are just like very diverged populations of modern humans. Or like, this is another thing that's hard to, this is another thing. Like how many genomes difference do you have to be before you're not modern human anymore? Instead of, you know, how many genomes different do you have to be and how diverged do our ancestors have to be to be thinking about like an archaic human versus a Homo sapiens? Especially when you're talking about Africa, which is the core region of human evolution. How do geneticists draw that line? It's kind of making me feel like I'm treading into dangerous waters here. So I'm not gonna go any further because I'm just unqualified to talk about that. But that is an interesting question for a geneticist. How does a geneticist think of modern human versus archaic human in terms of like, from a genomic perspective? How different does it have to be before it crosses that line into archaic human? Interesting to ponder about. Okay, it's 7 a.m. guys. The sun is up. I have been kept up all night pondering these things. Yeah, I know it's a little different video than what I usually make, but I just had a lot of fun on Flynn Dibble's stream. I'll put the link in the description. And I just wanted to talk about more things that are on my mind, that are keeping me up at night. Apologies to my dear wife when I'm tossing and turning, pondering the ins and outs of human evolution. She's used to it by now. Thank you for watching. See you on the next one.