Over millennia earth has seen and lost countless living species. None is more well-known than the disappearance of the dinosaurs 65 million years ago. For many epochs, mega-reptiles dominated the planet until an asteroid crashed into the Gulf of Mexico sending these creatures into the history books. Such large spans of times make these events difficult to comprehend. Most people may not realize that a comparable event occurred in the prehistoric period before human civilization arises. This is the story of the Younger Dryas event and the megafauna extinction.
It is hard to picture just 12 000 years ago earth was at the end of the last Ice Age. North America was a swampy marshland and was home to the largest population of megafauna found anywhere on the planet. Today these lumbering land creatures are mainly confined to herds across the plains of Africa.
How did such a dominant array of species disappear? It took one of the most unprecedented sets of conditions seen on earth, those that ended the last great ice age.
The Younger Dryas event describes the climatic period as the earth moved out of the ice age.
Here’s the full transcript for this episode:
Steven: Welcome to The Human Origin Project, where we explore The Science of You. To keep up to date go to our iTunes channel and subscribe and please leave a review if you enjoyed today’s show.
Hello, welcome to the show. Today we are going to be discussing the megafauna extinction that occurred in North America right at the period of the Younger Dryas event when 75% of megafauna and living across North America disappeared suddenly.
The evidence as to how they disappeared, and what really happened, and the many scientific fields that are showing that the Younger Dryas event could have potentially been a catastrophic level extinction that may even rival some of the previous extinctions on our planet.
We discuss this in the context of how this relates to human prehistory and really, why would the agricultural revolution and our history and modern civilization begin after such a tumultuous time. I hope you enjoy today’s episode on the Younger Dryas event extinction and megafauna of North America. Hey, Stefan, how is it going, man?
Stefan: [0:01:19] I’m doing all right. I’m doing good. It’s pretty early over here but I feel a bit better. We started before the sun come up but now the sun has risen so I’m feeling a bit more like myself, which is good. How are you doing?
Steven: [0:01:32] I’m good. We are going to have to work out a room to record these where there is natural light because we are kind of sitting in the aluminated room very early.
I’m just trying to reposition my life so that I’m cycling back into both not having artificial light before the sun comes up, after the sun and also get darkness is important too. We are going to go into that later but anyway so that’s a little tidbit. We are sitting in a very bright room at the moment early in the morning.
Today we are going to go to a really interesting topic. It’s about the mass extinctions of the North American megafauna. It seems a little bit random in The Human Origin Project but this is an important line of evidence. We’ve been following it.
There’s a swath of researchers looking at this. But it’s also somewhat not conventionally discussed that there was quite a big event that occurred across the planet. It had to do with the North America ice shift and what the North American continent looked like at the end of the last Ice Age.
Stefan: [0:02:48] Yeah, it was a very different place and that’s something that I had no idea about until I started looking into it. I think understanding that the world was a very different place up until this Younger Dryas event happened 12000, 14000 years ago. It really changes your understanding of the earth and our place on it. It was almost like starting from scratch again for most of the people on the planet at that time.
Steven: [0:01:18] If you are not familiar with what the Younger Dryas period is we did an earlier show on this. You can listen to where we did an overview and we’ll be covering this topic more. I remember probably my first line into looking at this was watching Al Gore’s An Inconvenient Truth in 2001.
He showed that there was an event where the North American ice cap melted and it flooded into and froze the Atlantic tides that actually direct a lot of both climates and ocean tide change around the world. I remember seeing that well that’s so important.
He kind of just mentioned it really quickly and then kind of went off as a potential ramification of global warming. If we have a melting period of these things on earth really shift quickly and North American ice shift melting is one of those events, isn’t it?
Stefan: [0:04:32] Yeah, just getting an understanding that the world was such a different place before the ice melted and that there are barely any remnants of that former world. Things changed so much after that event. The sea levels rose dramatically.
All the megafauna became extinct which is so important to this conversation because at the moment in the largest populations of megafauna are in Africa with giraffes and elephants and hippopotamus and rhinoceros and all those sorts of animals.
But you turn back to around the time of the Younger Dryas and North America was actually home to the most amount of megafauna. It was the most heavily populated area of megafauna in the entire world which is a very strange concept. You don’t really think about large animals.
You don’t really associate that with America. But back before the Younger Dryas period that was home to huge amounts of megafauna that were living there for thousands and thousands of years.
Steven: [0:05:42] Yeah, we have to remember that the planet was in full Ice Age, full glacial Ice Age and at 13000, 12000-year mark it begins to shift quite quickly, doesn’t it? This is the shift of the last year into our current one. On this borderline, you have this huge decimation of these huge mammals which we see today in Africa as you said, elephants and large mammals like that which humans fit into as well.
But when you look at the details of these animals, and I don’t know, you try and picture, it’s a very different place. The North American landscape would have been very different. It’s like a swampy marsh in a way that sea levels were much lower. This is during the Ice Age when sea levels are low and temperatures are different and then suddenly there was a big shift.
Stefan: [0:06:45] Yeah, and you can still say the scars a little across North America how big the ships were in terms of the geological record as the ice melted and flooded through the oceans that had to flow somewhere.
There are these extinct river systems and cataracts and huge destroyed landscapes all across North America where this ice flooded through and filled the oceans.
Just to paint a bit of a picture of North America before the megafauna became extinct, there were giant slots that I think we are up to 10 meters tall, giant armadillos, the horses, huge camels, a few species of elephants which I didn’t know until I started researching this, giant armadillos. They had an animal a dire wolf which was thought to be as big as a horse.
Steven: [0:07:40] They sound terrible.
Stefan: [0:07:41] Yeah. Try to picture living through this period, just trying to survive would be difficult. Mastodons, there were lots of species of mammoths, American lions, the giant beavers. There are these stories of Native American tribes talking about the beavers being so big that if a beaver’s den flooded it would potentially wipe out a whole village.
Steven: [0:08:06] Wow, really? I’ve never heard of that.
Stefan: [0:08:07] Yeah, because they were like 20 feet tall.
Steven: [0:08:13] And they would make a den it would just flood, wow.
Stefan: [0:08:16] Yeah. So you’ve just got to picture this world of huge animals. There are a lot of cases of them wanting to attack people. Back in the day just trying to get by and live a simple life would have been pretty difficult because you’d have to be constantly looking over your shoulder and try not to get eaten or attacked.
Steven: [0:08:40] I wonder if they hunted. I wonder if they know much about whether they hunted humans as such. I guess the dire wolf would.
Stefan: [0:08:47] Yeah. I guess there were a lot more animals for them to eat as well. But I’m sure they got the taste for humans at some point.
Steven: [0:09:00] There were some of the biggest land-dwelling mammals ever to really walk in this period too, weren’t there? We go back to larger reptiles like dinosaurs. But these are in some cases comparable. It’s mind-blowing. The sloths are huge. And talking about larger than a modern-day elephant?
Stefan: [0:09:32] Yeah, there were I think 30 feet which if you think an average, say average human’s six feet, that’s five times, five people standing on top of each other’s shoulders is one of these things and there were thousands of them roaming around the continent.
And then something happened which no one can explain that suddenly saw all of this megafauna just that vanish. They all died seemingly in the blink of an eye. I have no idea how to explain that one day they were there and then the next day they weren’t.
It wasn’t as sudden as that but in many cases, most of this megafauna went extinct just after the Younger Dryas event happened. There were isolated examples of mammoths surviving in different parts of the world in small numbers but the predominant number of the megafauna of just vanished from the record.
Steven: [0:10:35] So the earth is exiting the last Ice Age from 19000 years and these animals are all living in North America. And then at 12800 years they basically fall off the radar, don’t they?
Stefan: [0:10:51] Yeah and it’s hard to pinpoint exactly when because the Younger Dryas seemed to be a few isolated events, sort of a few thousand years of intense global change. But when all that sort of settled and the temperature and the earth stabilized there was no more megafauna in North America.
They’ve even found evidence all across the continent in North America of this black matte layer which I think we went into our Younger Dryas podcast. But it’s just this layer of black soot. They think it was caused by hundreds of years of soggy wet ground that sort of decomposed and rotted and then the sediment layout was built on top of that.
But everywhere that they’ve excavated there’s evidence for these megafauna bones below this black matte layer, all sorts of megafauna. But then above the megafauna, they haven’t found any bones.
Steven: [0:11:55] Above the black matte.
Stefan: [0:11:56] Yes, sort of like capping off this extinction event.
Steven: [0:12:00] So within the geological records and the fossils they dig up so you can begin to date all through this period and we don’t see them anymore. And as you say there were isolated instances of because one of the most well-known is a woolly mammoth.
There were many woolly mammoths in North America. They are these huge mammals. But some of the woolly mammoths lived in Siberia for a bit longer so they seemed to have- isolated pockets still survived.
Stefan: [0:12:42] Yeah, it seemed like North America was ground zero for these events because the ice cap was just above it. When these changes happened all the water sort of flooded through. That was kind of like the epicenter of this disaster or whatever it was.
The mammoths are interesting because there have been a lot of people trying to work out what exactly happened to them because there have been so many instances of these mammals being found with really disfigured bones and smashed up hip bones.
You think of a mammoth is something like five tons of weight and they found their skeletons of these moments where their feet were still on the ground and their bodies have been snapped back clean. The evidence for their legs to be broken for the hips to be broken, their tasks to be clean snapped off.
Steven: [0:13:45] They are large kind of mass grave sites too and even flash-freezing instances where they find what they were eating basically and undigested in their mouth and digestive system which means they can get a chance to work through that. It tells about the conditions that they died in. There’s a lot of this, isn’t there?
Stefan: [0:14:09] Yeah. One part of the event is that this insane power that seems to have hit the earth with these bones and these destroyed carcasses and things. But then on the other side, there’s the climate factor where these huge mammals were flash-frozen all the way through up to the point of undigested food in their stomachs.
I think even there are stories of finding these mammoths and all hunters feeding the meat to their dogs because it was still edible because it was still so fresh after being frozen for 10000 plus years.
Steven: [0:14:49] It’s interesting. It’s kind of like a murder scene. We talked about this a little bit in the Younger Dryas that it seems like you are piecing together a story of something that happens that was potentially quite harrowing, definitely for the poor megafauna that used to walk on the earth. But the numbers are amazing. It’s quite mindboggling to the extent of the number of species that disappeared that these young Younger Dryas boundary.
Stefan: [0:15:27] I think when Charles Darwin was going through the Americas he had this really long eloquent quote about what caused these events. And it was something like, the entire framework of the globe must have been shaken for so many species to go extinct.
It was like he saw evidence of it, not just in North America but in the southern end of Patagonia, all through Brazil, in Peru. He couldn’t explain it and we still can explain it. But the more evidence that’s coming forward seems to paint this really catastrophic picture.
Steven: [0:16:08] There are different theories too because there are the megafauna extinctions. There’s one in Australia from around 50000 South Americans as you said around 13000. The so the general consensus is that this was a gradual process.
But as Darwin was alluding to there is a lot of evidence to suggest maybe it was sudden, as you say, the Younger Dryas period, everything that we’ve uncovered to this point is suggesting something quite sudden happened and also quite violent.
Stefan: [0:16:47] Yeah, that’s part of our way of thinking at the moment in terms of science and geology, especially that everything happens very slowly. It was seen that this period was just a slow, gradual process because we are looking at it through the framework of this gradualistic ideology that’s kind of crept into science.
It sort of reminds me of the other extinction events that we’ve talked about, on The Human Origin Project before. This event would be classed as a mass extinction event but it’s not really understood that way yet because we are still piecing it all together.
Steven: [0:17:31] The 75% of all megafauna on the planet and then 35 [0:17:36], 120 species, 90 species of birds. If birds are affected obviously the ecosystems are imbalanced. It’s unbelievable, isn’t it?
Stefan: [0:17:47] Yeah, 50% of all the animals above 32 kilos disappeared during that Younger Dryas even and every species above 1000 kilograms in North America disappeared, just gone. We always think of mass extinctions tied to animals but they were human populations at this time on the planet.
I think the estimates are about five million people living in North America at that time. There are countless examples of campsites being abruptly abandonment and that side, evidence of popular huge population declines in North America and South America and other parts of the world.
Steven: [0:18:45] Mines that have been populated for generations, so we are abstracting certain stones just completely.
Stefan: [0:18:47] Yeah, and like they find these abandoned quarry sites with their tools. It’s as if something happened so quickly that they just dropped their tools and left. If you isolate these things, they don’t seem too strange but when you start saying that they are all sort of tied in together and tied into this time period it’s a bit of a grim picture.
Steven: [0:19:10] Yes it’s grim but it’s important to know. I think with these kinds of things for me, I just want to know. So it is grim but it’s important to know actually what happened. I don’t want to kind of have the wool pulled over my eyes and just to think that everything was hunky-dory cycles through history.
Potentially avoiding these kinds of events or points in history might be understanding them. Science has really moved forward in a way to collate a lot of different fields. There’s a lot of data too, so much data. When you look at, for instance, digging up a woolly mammoth, fossils, and everything it’s a lot of work and it took decades and decades and decades.
We are at the point now where we’ve amassed enough data to start thinking about it. But generally, there are many theories put together which is the scientific process. The most accepted theory is the idea of overhunting, isn’t it?
Stefan: [0:20:19] Yeah, the idea that humans are responsible for these megafauna extinctions which would make sense if it was on a smaller scale, you could believe it. But they are talking about in North America the population of mammoths alone being over five million and at that time there were only five million people. So, it’s like, that’s everyone.
Steven: [0:20:45] It’s one mammoth per person.
Stefan: [0:20:46] Yeah and these mammoths wouldn’t have been friendly. They are so big. If you look at pictures of them online they are bigger than elephants, and they’ve got tusks twice as long. They are huge. Try to hunt those things with a spear, even if you’ve got 20 people.
I think there are a few tribes in Africa who used to hunt elephants, and even that took them 20 tribesmen and it was only really ceremonial because it was so insanely difficult, it was just stupid.
Steven: [0:21:23] And then there’s not a lot of evidence to show that they really have the means, capabilities or even desire. The other thing too if you think about the environment there so many other species that you can go and hunt to feed on. A woolly mammoth feels like the last kind of thing, maybe not the last but high on the high difficulty rating.
Stefan: [0:21:47] Yeah and if you are hunting a mammoth you kill one mammoth that’s tons and tons of meat. It doesn’t really add up that you would need to hunt so many mammoths and so quickly that they go extinct.
It makes sense one or two here or there or a few isolated incidents but all of them gone that quickly. I think the main culture that was in North America at the time was known as the Clovis Culture and their predominant diet was not mammoth. It was a turtle and other berries and things like that.
Steven: [0:22:35] The studies have shown that, haven’t they?
Stefan: [0:22:36] Yeah.
Steven: [0:22:38] The numbers themselves it’s estimated up to 12 million mammoths across North America which is just staggering. There were four or five million people. We probably don’t have solid numbers on the human population but you can assume to a certain extent.
Stefan: [0:22:56] Yeah, I’m not sure if the mammoth population was global.
Steven: [0:23:00] It might have been global, yeah.
Stefan: [0:23:04] Even now, today, in Siberia as the permafrost is melting naturally they are finding these huge deposits of mammoths that were frozen that are now becoming available for people to take. There’s this really big, ivory trade that’s kind of reborn where they are selling these mammoth tusks which are still in perfect condition because they are frozen so quickly and they’ve been frozen for 12000 years.
Steven: [0:23:34] So they are finding like tons and tons of mammoth in Siberia. Wow.
Stefan: [0:23:41] Yeah, I don’t think we talked about it before but there are all these instances of these mammoths in North America that they found where their tusks have been obliterated or it’s like they’ve been shot with a shotgun and there are bits of rock and bits of soot and ash that have been like burned into the tusks themselves which would have required insane amounts of force.
Steven: [0:24:03] This goes into other ideas. There are other theories to try and explain this mega extinction and all of this evidence. Obviously, human intervention could have been a factor but there are other theories too in the support in the scientific process to explore them. And so as you said there are a lot of instances where a mammoth is sitting with its feet and its body’s been ripped off which you can imagine the force required to do that.
It has come about that the potential there was a Younger Dryas event, or an impact or maybe some kind of solar event. It would have had to been pretty significant to knock off so many megafaunas. As you said there is a body of evidence which isn’t accepted yet but it keeps mounting.
It’s an interesting picture that was seen. As always we always have to follow the evidence. But the black matte layer doesn’t suggest it’s is inconclusive of a comet here but it does show that there were changes in the environment. It dates exactly to that 12800 years.
The megafauna of North America, all the mammoth, sits below that level, doesn’t it? It’s very similar to the dinosaurs, in a way where they saw that there was a platinum-rich layer that ended up being the meteor that hit in the Yucatan.
Stefan: [0:25:51] Yeah and the interesting thing about that is they found a platinum-rich layer in the sediment dating to the Younger Dryas period.
Steven: [0:25:59] Platinum or iridium? It’s one of them, isn’t it?
Stefan: [0:26:00] Yeah. Well, there’s iridium and there’s platinum. There’s like platinum group metals. I think when the earth forms they are all drawn to the core because they are so heavy. So when they are not at the core it sort of raises questions as to them having to have been placed there from outside.
Steven: [0:26:18] They didn’t come from any terrestrial.
Stefan: [0:26:20] Yeah. Another thing with the extinction event that we’ve been talking about is no one can explain how the ice melted so quickly across North America because scientists that have been looking at it can’t find any evidence, any terrestrial evidence, anything that would happen on the earth to cause such a quick and such a large amount of ice to melt. So no natural disasters, no volcano would be big enough to melt that amount of ice which was two miles thick and some.
Steven: [0:26:57] Two miles thick sitting over most of the northern part of the United States of America and covering Canada.
Stefan: [0:27:03] And Canada, yeah, two miles.
Steven: [0:27:04] That is mind-boggling. What’s the volume of ice?
Stefan: [0:27:07] I think there were 6 million cubic miles. Or maybe it was 10 million cubic miles. Whatever it was there were four more million cubic miles than there is today.
No one can explain how it melted so quickly which would give more credence to the idea of an impact or something from outer space or something that is yet to be identified that could have helped cause those events which would also explain why these poor mammoths were so dismembered and disfigured.
Steven: [0:27:47] It’s basically like draw a line from Portland across to New York or something like that and imagine two miles up there’s ice sitting across that line right up through Canada. It’s unbelievable. Yet there is no explanation as to how that ice disappeared.
It does provide circumstantial evidence as to potentially did that energy to break that ice to get rid of that ice. It does take my mind back to that Inconvenient Truth seeing that Atlantic current being broken via the melting of the North American ice cap.
Was there an event there? Is the megafauna extinction all of the evidence you see, or potentially a violent event the number of species that went missing, 12 million mammals across the planet, roughly a ton or more is unbelievable. And so to me that definitely paints a picture of something that suggests it could.
There are other theories to this as well and climate changes one. But the Greenland ice cores really do paint that quite vividly that there is climate change but I don’t think it’s in the climate change that we talk about today.
Stefan: [0:29:15] And if it was climate change, if it was a temperature change that caused the melting of the ice it would have taken thousands of years longer than it did. Even though the climate change that happened during the Younger Dryas period was significant in terms of our context it wasn’t large enough to melt all the ice and to cause all these changes so quickly. It should have been a very gradual process if it was purely temperature change.
Steven: [0:29:46] Because you know if it was ice, it was a 10 to 15-degree drop, wasn’t it?
Stefan: [0:29:53] Yeah. I mean we are talking about a few degrees now which is going to completely change the whole fabric of the entire world with some cultures having to abandon places that they’ve lived because of sea level rise species going extinct, coral reefs dying out. That’s only one or two degrees. Imagine 10 degrees within a lifetime.
Steven: [0:30:19] There are scientists talking about climate change as a mode for megafauna extinction. You have to remember too that temperature really is a result of other factors. For instance, we attribute modern climate change to the release of carbon dioxide.
So if we read those temperature changes in the Iceland core like the scientists did, you do have to wonder what caused that. And so for such a big fluctuation, it’s just reading on what’s happening. It just seems to that there is something missing in that picture of just saying that climate change caused such a huge event across the planet. Of course, it did but there has to be another part of the picture.
Stefan: [0:31:10] Yeah, I think learning about these mass extinction events and the prehistoric climate change and all these different factors going in there are so many dynamic factors that go into these events. It’s really hard to isolate. You can talk about one but you talk about one, you miss another 5 or 10.
I think it’s really important to try and that’s why I’ve been so interested in this mass extinction topic because you are looking at one part of a huge picture, and once you can understand that part, the rest of the picture makes a bit more sense, to me, anyway.
Steven: [0:31:49] Well, completely as well. You mentioned Darwin before but this does go towards an evolutionary discussion as well because all life on earth as it exists today, is dependent on previous iterations of life. We see it is evolving too but really there are also clearing out certain platforms in order for others to come.
The dinosaur is a great example of that. It took a long time for us to really admit the dinosaurs was a catastrophic event and really work that out as to what caused this extinction. This is 65 million years ago and there are a number of extinctions that happened over our history.
But none are as close to home as this Younger Dryas one. It’s not discussed in that kind of context where this thing that happened 12000 years ago preempted human civilization. So we rise directly after and we don’t see that in an evolutionary sense. But what was that?
What caused that clearance factor? What were the details that really caused us to raise it? It really makes me think about how our prehistory is intimately linked to the planet. But it also goes into evolution. We see it as a gradual process but we know now that there have been a number of these.
There are five main extinctions. Steven Gould talked about this. He was a big advocate for the idea of mass extinctions and punctuated evolution where we see clear points that delineate between sentences as they would, whereas, or periods of time the megafauna leaving helped us to become who we are.
Stefan: [0:33:49] I think as well. You think of mass extinction events as potentially shifting or taking out the top few predators in an environment, which is exactly what happened 12000 years ago. That’s why I feel like this is so important because it was so fundamental in our society developing and our culture rising.
It wasn’t until that point that the climate on earth stabilized because civilization is very heavily tied into climate. You even look back to the Dark Ages when it was literally there were months of darkness across the UK. There’s even evidence for almost the entire population of Scotland having to leave Scotland because they couldn’t live there anymore.
Steven: [0:34:48] They are pretty much doing that now, aren’t they?
Stefan: [0:34:52] But yeah, it’s crazy to think how connected we are to the climate on earth. We can’t imagine it because it hasn’t happened for so long. But say there was a volcano eruption and huge amounts of soot were thrown into the air and we wouldn’t see the sun for months.
I can’t remember what year it was but there was a year they call, I think it was in the 1800s, they call it the year without the summer in America. There was a volcano eruption and that exact thing happened. There as an entire year or 18 months with no sunshine.
It would completely destroy the progress that we’ve made up to this point. You’d almost have to start again because you wouldn’t be able to grow food. You wouldn’t be able to sustain life without the sun.
Steven: [0:35:50] Yeah, the North American megafauna extinction and the Younger Dryas event, I think it should make you think about these things. That’s really what the purpose of this episode is about is to get us to stoke the fires of understanding.
We just want to understand what really happened in history and extinctions are a part of that. This is a big extinction that happened almost instantaneously to the rise of modern civilization. When you put it in the perspective of life on earth maybe we should put it in the great extinctions because humans have changed the earth since then. For me, I think we should really understand that.
Stefan: [0:36:33] You always think of mass extinctions as happening millions of years ago like things that used to happen to the earth but now that doesn’t really affect us.
Steven: [0:36:41] Geologically, this is a blink of an eye.
Stefan: [0:36:45] Yeah, it’s insane.
Steven: [0:36:49] Yeah. But overall we are going to be covering this topic more. The North American megafauna is a mystery, it’s a very big murder mystery, maybe not a murder mystery but it’s a very interesting one at that. It’s intriguing to trace back what these amazing animals were doing on the planet and trying to find out what happened. We’ll be covering this topic more.
Stefan: [0:37:15] Yeah and if there’s anything, any other subjects or anything that we’ve missed to do with the megafauna please write to us at the humanoriginproject.com and let us know your thoughts and let us know other avenues you’d like us to explore or talk about.
Steven: [0:37:30] All right, good show. Next week we are going to maybe be talking about Halloween, let’s go with that.
Stefan: [0:37:40] Where did that come from? Yeah, let’s talk about Halloween.
Steven: [0:37:41] Let’s talk about Halloween.
Stefan: [0:37:42] Sounds good.
Steven: [0:37:43] All right. We’ll see you guys next week.
Stefan: [0:37:45] See you.
Steven: [0:37:47] Thank you for listening to today’s show. For more information, you can read the full transcript, articles and discussion on our website humanoriginproject.com. You can visit us on social media at Human Origin Project on Facebook and The Human Origin Project on Instagram.
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