ExtinctZoo - The Earth's First Known Plague

Episode Date: May 10, 2025

If you've watched some of my recent videos, then you'll know that the neolithic kind of sucked, it just wasn't fun, well turns out that somehow it was even worse than we once thought, like way way worse.Check out the website: extinctzoo.org

No one goes to Hank's for his spreadsheets. They go for a darn good pizza. Lately, though, the shop's been quiet. So Hank decides to bring back the $1 slice. He asks Copilot in Microsoft Excel to look at his sales and costs to help him see if he can afford it. Co-pilot shows Hank where the money's going and which little extras make the dollar slice work.

Now, Hank has a line out the door. Hank makes the pizza. Co-Pilot handles the spreadsheets. Learn more at M365Copilot.com slash work. 5,000 years ago, in present-day Latvia, a stone-aged man, seemingly in his prime, was drawing his final breaths. He was only between 20 and 30 years old, had no clear visible injuries and wasn't starving or dehydrated. At the same time, a woman, also in apparent good health and equally young, was spending her last moments on Earth too, enduring the exact same agony. However, despite their fates being identical, the two did not actually know each other, nor were they even neighbors, as she was located hundreds of miles or kilometers.

away in Sweden, but within a few days both would be dead, as would countless others, all slain by an invisible killer who thousands of years later is being blamed as a potential culprit behind the partial collapse of human civilization in the end days of the Neolithic. And the murder suspect in question is one humanity knows all too well. Yersinia pestis, a gram-negative bacterium, which you likely have never heard of, but almost definitely know the name of the disease it creates, the plague. Yes, the very same plague that brought us the likes of the Black Death and the Plague of Justinian, two of the deadliest pandemics of all time, which combined possibly killed hundreds and millions

of people. And now, some researchers think that this trouble may have also been behind an ancient plague that decimated populations across Eurasia thousands of years before. For quite a while, researchers have been aware that Yersinia pestis was an ancient pathogen, with DNA suggesting an emergence of between 7,000 and 6,000 years ago, after it had likely evolved from Yersinia pseudotorberculosis. But the going idea was that it didn't do anything interesting for a long time, only going ham during the medieval ages much later on.

However, this idea started to change after researchers began to stumble upon not one, but dozens and dozens of individuals dated to the Neolithic who all had Yersinia pestis preserved in their teeth and skulls, indicating that it had been circulating in their blood and very likely killed them, is all three kinds of the plague, septicemic, bubonic, and pneumonic, boasts very high mortality rates, in some cases averaging 93% without treatment. So in other words, they were likely doomed. But despite this alarming find, no one was really surprised, as ultimately infectious diseases

were no novelty back then. And besides the plague, many ancient humans have been found with evidence of fatal diseases. Thus, no one believed these specimens represented anything too unusual or sinister, rather just a daily part of ancient life. Until that is, bodies of the plague kept popping up over and over again. and not just in one spot, but across large geographical distances. And then, researchers started to find them amongst families, and then in mass graves. And what really started to finally turn heads was the timing of all these deaths,

as they happened within a relatively short period and were awfully close to a rather strange and mysterious event, the Neolithic decline. And something else that will turn heads, hopefully, is this announcement. So I teased this about a month ago, but we have just launched our website and our first merch. We've got the classic Time Travelers Guide to Dinosaur identification for when you decide to take your first field trip into the past, and then we even have our very own KemKem Group field guide. So if you decide to take a detour to Morocco and have a safari 95 million years ago,

we've got to you. Anyways, I'm not going to spend too long talking about this, but if you like dinosaurs, paleo art, or just posters in general, and want to support the channel, please do go check it out. I mean, I don't know about you, but this poster does be looking pretty good on my wall, so might on yours too. And I do also want to say, thank you guys for all your support over the years. You guys have really made this possible.

So thanks. And now, back to the video. This was an enigmatic period that took place between 3,450 and 3,000 BC, and saw populations across Eurasia nose dive by up to 50% compared to their previous peaks. Essentially erasing, nearly a thousand years worth of population growth, which had come following the expansion and advancement of agriculture. Now, no one knew exactly what caused this event. But it did seem to align with all these plague specimens researchers were finding.

And what's more is that humanity was now at a point where a widespread pandemic made feasible sense. As large settlements, dubbed mega-settlements, were becoming more and more common. And while they were not traditional cities, many, like Maidenetsky in Ukraine, still contained thousands of buildings, which supported tens of thousands of people, about 50,000 to be exact. And in such settlements, where lots of people lived close to one another, in sanitation practices were a, not the best, pathogens like Yersinia pestis were bound to thrive. Not to mention that within these dwellings,

large storages of grain further added indirect support for an ancient plague, as it would have attracted large amounts of rodents to these areas. Bad news, seeing that these little critters and the fleas that they carry are reservoirs for the bacteria. In other words, a recipe for disaster. And sure enough, many of these large settlements also seem to collapse around this time, and in certain cases would contain dwellings that had not only been abandoned but burnt to the ground, something you tend to do when you want to make sure that whatever is inside it never gets out.

So all these signs hinted that maybe something awful had been occurring in the lands, which was much more than your simple flu season, in prompting a group of researchers to take a better look and not only the already-known plague specimens, but also other burial sites in general that had not yet been researched. And the results were quite telling. as they found that this ancient plague was much more prevalent than originally thought, as between the over 100 skeletons analyzed from across Scandinavia,

they found that 17% of all of them have been infected by the plague and then succumbed to it. And even more grim details were unearthed when a large family was found buried together in a single site. It contained 38 individuals who were closely related and showed even higher rates of infection than the 17% as 12 of them have been found with a bacteria. So about 32% approximately, equal to the lower estimates for the percent of the populations killed by major pandemics like the Black Death. Additionally, this family seemed to have been super-screwed, as they had suffered from the pneumonic plague, the rarest yet deadly as kind seen today, which consists of a severe

aggressive lung infection that in certain situations can kill untreated victims in under two days. And during this ancient outbreak, it may have been more common than presently, and is also also the only known plague type that can transmit from person to person, which it does so when bacteria containing droplets are inhaled from an infected individual. Now what's not clear is if this pandemic consisted mainly of this pneumonia type, or if it was a mix and match of all three. But some do think that all were present, as some of the oldest plague victims show signs of having suffered from both septicemic and bubonic infections.

There is also the added debate that at the time, the ancient bacteria had yet to evolve ability to survive in the gut of a flea, which makes you wonder how it was originally transmitted. Another interesting discovery made within this unfortunate family was that the ancient outbreak had lasted far longer than anticipated. Because of the buried members, it turns out that not all had belonged to just one generation, but rather six that spanned over 120 years. And opposed to seeing the infection limited to just one generation, it was discovered that multiple had been impacted, while others were left largely untouched, and thus leading to the concordial. that there had been three distinct waves of this plague.

The first two, which didn't appear to be that virulent or deadly, while the third caused major carnage, which together the researchers believed enough to be the sole explanation behind the downfall of large settlements associated with the Neolithic decline. And if the plague really was this bad, living in ancient Eurasia must have been an absolute nightmare for anyone. And along with the disappearance of settlements

was also the disappearance of all the cool megaliths that people had been building, as there simply wasn't anyone left to build them. And then the people themselves became hard to find too. Well, at least the friendly ones, as violence seemed to be higher in this apocalyptic wasteland as well. And sure enough, multiple masquerades from around 5,000 years ago, are known of, which contain both civilians, fallen warriors, and in at least one case, a tragically murdered family. And we know that often during bad health crises, crime and violence typically do rise,

as seen not only with the Black Death, but also even in pandemics during modern times. So this is all to say that life surely sucked back in those days, and that's before factoring in any of the other things which made the Neolithic a nightmare. And while it's impossible to say for certain just how bad this event truly was, some estimates believe that possibly 5 million or so humans perish by the end of it, which relatively speaking made it deadlier than both in 1918 Spanish influenza pandemic and the AIDS pandemic as well. There was, however, a silver lining in all of this, albeit a very, very thin one, which was

that the strain of Yersinia pestis, responsible for this event, was still somehow less infectious and fatal than the one behind the Black Death. So hooray for that, I guess. But when it was all said and done, the Neolithic decline would take thousands of years for humans to recover from, and in some areas, population levels didn't return to what they were for over 3,000 years. Now, I will say that while it's widely agreed that the Neolithic did see some major declines in human population, not everyone actually thinks that this ancient plague was to blame. To be exact, another group of researchers which analyzed over 100 bones in Germany, found that the rate of infection was much lower than 17%, being closer to between 1.5 and 5%. This is obviously still very high, but paints a less grim picture. And at these numbers, they argue that the plague alone could not fully explain the drastic drop seen throughout the late Neolithic.

But it is definitely possible that the severity of the outbreak widely varied across Eurasia, where certain areas got absolutely ravaged, while others less so. Additionally, some believe that it may have been a mix of varying factors that contributed to the overall decline, plague included. And over the years, other ideas have arisen to explain this mysterious event. One of the more interesting ones being that universal and all-consuming fear is actually to blame. Now, if you've seen my other video about the Neolithic bottleneck, then you'll know that this period was no stranger to bad times, and this included violence that was on a level which is honestly hard to comprehend, and was so bad that it's possibly reflected in our own DNA.

And the fear hypothesis claims that this warfare was so brutal that people essentially became slaves to the fear and distress of war, compelling them to all congregate in these safer mega-settlements, leading to overcrowding, which then decreased the fertility rates while also increasing the mortality rates, and ultimately resulting in a population crash. Another prominent and even longer-standing idea is that agriculture, which had allowed for populations to boom in the first place, was simply undergoing a rough time, as it was around this period that the earth had begun to lower in temperatures, and thus likely disrupting crops and possibly leading to poor yields, causing mass famines and decreased growth. And ultimately, the answer might

be a combination of all three. Whatever does turn out to be the true cause behind the Neolithic decline, I think it's still safe to say that in the end, the Neolithic period just sucked. Thanks for watching, and until next time, on Extinct Zoo.