Younger Dryas Meteorite

It has been suggested that a large meteorite was responsible for an odd  climatic twitch from about 12,800 to 11,500 years ago (the Younger Dryas , a temporary return to glacial conditions in the Northern Hemisphere) and for the extinction of the large mammals of North America.  They hypothesize air bursts or impact of a swarm of meteors , centered around the Great Lakes.  Probably this is all nonsense.

The topic of the Holocene extinction of megafauna seems to bring out the crazy in people. In my opinion, the people supporting this Younger Dryas impact hypothesis are nuts, and half of their opponents are nuts as well.

Let’s just think about this hypothesis as an explanation of megafaunal extinction.  There certainly was such an extinction:  North America had mammoths, mastodons, giant ground sloths, giant turtles, glyptodonts, giant armadillos, short-faced bears, sabertooths, something similar to the African lion (Felis Atrox), etc. No longer, which is just as well.

The problem for that meteorite explanation of North Ammerican megafaunal extinction is that South America had an even more varied set of megafauna (gomphotheriums, toxodonts, macrauchenia, glyptodonts, giant sloths, etc) and they went extinct around the same time (probably a few hundred years later).  There’s no way for a hit around the Great Lakes to wipe out stuff in Patagonia, barring a huge, dinosaur-killer type hit that throws tremendous amount of debris into suborbital trajectories.  But that would have hit the entire world…  Didn’t happen.





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71 Responses to Younger Dryas Meteorite

  1. georgesdelatour says:

    During the last Ice Age sea levels were lower. The Bering Strait was a land bridge connecting Asia and America, but the human route to America was blocked by a huge glacier. As the world warmed, there was a moment when the glacier had melted enough to open a corridor into the Americas, but sea levels hadn’t yet isolated America from Asia. That’s probably when mammoth-hunting humans crossed continents.

    Once in America, the humans colonised the virgin continent, hunting the large mammals to extinction as they expanded.

    • Anonymous says:

      And where is your evidence to back up such a claim. I find it very hard that a population of about 4-5 million Humans and every person, young and old, generation after generation decided to go on a rampage to kill everything they saw. The only thing that people assume it was our ancestors fault is the time frame in which humans reached a continent. There is no actually evidence that humans hunting every animal. Now I’m sure that few species extinctions at the time is the fault of some humans, but to say that they just decided one day to just go on a safari hunt on every continent just for the hell of it seems a bit absurd.

      • gcochran9 says:

        People became more common by the usual baby-making process, and they ate what they could catch. So predation increased rapidly. Animals that were easy to catch, and had low reproductive rates, went extinct.

        Same thing happened in Australia, where all the largest creatures disappeared not long after people showed up. Same thing in Madagascar and New Zealand, much more recently.

      • Sandgroper says:

        And in Australia, it happened once on the mainland, and then again when Tasmania became accessible to humans a few thousands of years later. So the circumstantial evidence is really mounting here that humans were implicated, if not the sole contributing cause.

  2. d0jistar says:

    “No longer, which is just as well.”

    You must be joking! Who wouldn’t want to hunt sabertooths or see frickin _Megatheria_ roaming around. I mean _giant ground sloths_ as big as modern elephants. Not to mention giant armadillos. The sheer awesomeness utterly boggles my mind.

    • kai says:

      Yeah, I’d like to see some too, best thing besides live dinosaurs…
      But I’d like to see them in a zoo, or better, in well closed reservations, from a large-enough/strong enough vehicle. I am not so positive seeing them in my yard….
      Just like south africans, who can still see their megafauna in the kruger park for example. But it is not nice to be close to a modern elephant without the appropriate protection. And a normal car is only appropriate because u can get out quick enough with it, not because of its frame or bulk…

    • Greying Wanderer says:

      I’d like to see all that but from a tank.

      • kai says:

        A tank should do. Giant sloths, not dangerous? Have you seen the front claws of those things? Anyway, betting on a large herbivore not to be dangerous when it share its territory with large carnivores is not a safe bet. After all, they have managed to not be eaten to extinction before encountering homo sapiens, and I suspect it was not by convincing the sabertooth about the merit of vegan diet….

    • feministx says:

      Omg. Why did the earlier humans have to be so frkikin hongry? Would be sooo cool to ride a giant sloth today!

    • Steve Sailer says:

      France’s cold, basically uninhabited Kerguelen Islands (a.k.a. Desolation Islands) in the far southern Indian Ocean would be a good place for a Jurassic Park of revived Ice Age megafauna for billionaires to hunt. The main island is over 2,500 square miles, and they’re a 2000 mile swim from the nearest land.

  3. misdreavus says:

    Some people have apparently made it their life’s ambition to wage perpetual war on Occam’s razor. I mean what gives?

    If I recall correctly, Pleistocene megafauna persisted in isolated pockets throughout the world long into the Holocene – examples include the Caribbean, islands off the coast of Siberia and Alaska, Mediterranean islands, etc. only to disappear shortly after the arrival of human colonists. (In the case of New Zealand, creatures such as the moa persisted until the past six to seven centuries, only to go extinct when the ancestors of the Maori first discovered the islands.) Yeah, I’m sure this is just a couple hundred coincidences in a row. Nothing to see here, folks!

  4. pauljaminet says:

    Of course, there were a number of extinctions in Africa c. 2 million years ago, about the same time humans developed effective social hunting methods. And other extinctions as human range expanded, eg elephants in the Middle East c. 400 kya. And the extinctions in Australia c. 48 kya.

    • The fourth doorman of the apocalypse says:

      The problem is that it’s raciss to suggest that the Noble Savages caused those extinctions.

      What to do? Ahhh, yes. Meteorites wont get you labelled a racissss.

    • The most likely explanation for the African extinctions in the Pleistocene (but not 2mya!) is most likely climatic because there were ecological changes at around that time there.

      Though the arrival of human hunters must have had an impact around the world, it may not be as drastic as people think. Hunters have an understandable interest in conserve their prey, and even the Maori attempted this with the moa on NZ. As such I would expect the impact of human impact to be greatest when culturally specialised human big game hunters move into a new region, or when new weapons (such as firearms) are invented or become introduced from outside. Whilst extinction through subsistence overhunting is a real and attested phenomenon, it seems only to happen on islands and even then extensive coexistence with humans is possible before a significant ecological impact may be demonstrable, think of the long occupation of Madagascar before the extinctions there.

      The collapse of ecosystems is a complex process, that shouldn’t really be oversimplified to a single cause whether it is meteorites or overkill.

      • gcochran9 says:

        Since there are no written records, how the hell would you know that the Maori tried to conserve the moa? A seance?

        There were massive extinctions in Australia and the Americas after people showed up: what do you mean, it only happened on islands? For that matter, lots of stuff disappeared in Eurasia and Africa too, spread over a longer period.

        Reverse Ockhamism. Why?

      • As for extinctions caused by overkill, there are a couple of reasons why the New Zealand ‘megafaunal’ extinctions were atypical. The moa, the only large prey animals available on Aoteoroa, were k-selected and because of the low biodiversity of potential large prey animals on New Zealand, the Maori had just a few k-selected species of large moa available as game. This means there was no other large game to switch to for easy protein when moa stocks dropped too low – unlike mammoth hunters they couldn’t just switch to buffalo. Besides, New Zealand is essentially two islands so the few large moa species were never as numerous as the Nearctic or Palearctic megafauna on continental mainlands, and smaller game populations are naturally vulnerable to a shockwave of efficient human predation in a way that the Pleistocene megafauna in the Americas and Eurasia were not.

      • Although I admit I don’t know very much about Maori culture, my understanding is that the moa had a predictable significance for native New Zealanders as large game species do elsewhere. Such cultural values have a clear ecological purpose and its intuitively difficult to accept that the Maori would show no interest whatsoever in preserving food stocks and their own ecological specialisation once they noticed their prey stocks were declining too much. Since I have actually heard it stated by a paleontologist that Maori had set aside no-hunting areas, I accepted it at face value because it was only common sense.

        I realise that any memories of prey management would have been passed on orally by the Maori until informants transmitted them to Anglo folklore collectors, but I don’t see this as a reason to dismiss it. After all, despite the time that had already passed since their extinction the moa were not merely some vague, native folk memory because indigenous cultural images of moa have since been proven strikingly accurate by paleontologists (ie. the feathered feet of the moa have since been preserved as fossils) although the Maori information was admittedly wrongful on occasion (ie. the folivorous moa were remembered by the Maori as probing mudflats for shellfish – though even this is maybe a misunderstanding of authentic ratite behaviour, because extinct island emus were also recorded by white settlers as frequenting shorelines.)

        Because I’m not particularly knowledgable about Maori culture I’m going to try and check the relevant folklore about moa hunting before I contribute any more.

      • Richard Sharpe says:

        At what point do you think there will be selection on humans to manage (husband) their prey species?

        While they are plentiful or when they are close to extinction.

        How long do you think this selection will take until it is effective?

      • Greying Wanderer says:

        “Hunters have an understandable interest in conserve their prey”

        I imagine it’s harder to judge or fine-tune with magafauna i.e. kill an animal for just 1/4 of the meat or possibly much less than 1/4 if stampede hunting was used.

        If those hunters had refrigerators there might still be mammoths.

        Also if megafauna had a longer life-cycle then that may have made it easier for hunters to make them go extinct. I’d imagine there’s a mathematical expression for that containing terms for biomass, food requirements, life-span and proportion of biomass edible without storage.

        Also makes you realize some traits of prey animals may have have evolved as a result of humans hunting them.

      • pauljaminet says:

        GW – yes, like gregariousness in African animals.

      • > instinct to preserve their prey
        Your tribe can kill a mammoth, or let some other tribe kill it.
        But what if all the tribes in an area are under one emperor?
        By the end of Roman Empire, Italy was mostly deforested, and the plant Silphium was hunted to extinction.
        Of course, Robin Hood was forbidden to hunt the King’s deer under pain of death. So European civilization eventually did learn about conservation.
        But yeah, I’m sure the Native Americans, who weren’t soulless and weighed down with original sin like Europeans, were born understanding how to conserve natural resources.

  5. panjoomby says:

    @misdreavus: “Some people have apparently made it their life’s ambition to wage perpetual war on Occam’s razor.” that is a stunningly superb quote, here & in many other contexts. well said!

    • Steve Sailer says:

      “Some people have apparently made it their life’s ambition to wage perpetual war on Occam’s razor.”

      Indeed. Change “life’s ambition” to “life’s work” or something similar and it works even better.

  6. Patrick Boyle says:

    Speaking of glyptodonts and crazy people you should read “1423” – the looniest early human history theory since Barry Fell.

    This is the theory that the Chinese explorer Zheng He who really did traverse the Indian Ocean to Africa in the early fifteenth century also circumnavigated North and South America, all of Asia the Artic and the Antarctic. In fact according to this account he went everywhere except Europe. Had he sailed around Europe of course his giant super ships would have been seen by literate men who were sailing about in their own ships.

    One of the odder claims of this whacko theory is that the Chinese saw glyptodonts in South America.

  7. Jim says:

    Is this story related to the stone tower in Massuchusetts, I think, for which a theory was advanced that it was constructed by Chinese explorers? An archaeological investigation of the tower demonstrated that it was built by English colonists and contemporary historical documents attesting to this were located. Before the Chinese theory another story was that it was constructed by Vikings.

  8. dearieme says:

    “the Chinese explorer Zheng He …”: he wasn’t an explorer – he travelled only to places already well known to the literate neighbours of the Chinese.

    “Had he sailed around Europe of course his giant super ships would have been seen by literate men who were sailing about in their own ships”: good God, you’re not implying that the rest of the world was illiterate, are you?

  9. Greying Wanderer says:

    There’s a potential match here between politically correct history and the solutrean theory. Make it so white people killed all the megafauna and then died out afterwards everywhere except Europe.

    • Thomas says:

      Yes but the Solutrean Theory says that the Solutreans came from Europe, not that they were necessarily European. The Solutreans could have been related to the American Indians, and for all we know they could have been pushed out of Europe by Europeans and driven westwards to the Atlantic. The later colonization of the Americas by Europeans which drove out the Indians could have been a recapitulation of what had happened in Europe thousands of years before.

  10. his WP blog seems to have problems with long comments, I guess blog comments weren’t meant for this. It keeps saying I’m making duplicate posts though when I click refresh they aren’t showing up. and when I make a short reply they show up instantly.

    Although I don’t know very much about Maori culture, my understanding is that the moa had a significance for native New Zealanders as large game species do elsewhere. Because it is intuitively difficult to accept that the Maori would show no interest whatsoever in preserving declining prey stocks and their own ecological specialisation should they have noticed the hunt was becoming unsustainable. I simply accepted it at face value when I heard from a paleontologist that the Maori set aside no-go areas to conserve their own game stocks,though he did not cite a source on this.

    Any memories of prey management would have been passed on orally by the Maori until informants eventually transmitted them to Anglo folklore collectors, but I don’t see this as a reason to dismiss their value. Despite the time that had already passed since their extinction the moa were not some vague, native memory because indigenous images of moa have since been proven strikingly accurate,for example the feathered feet of moa have since been discovered as fossils.

    Of course other prey animals disappeared alongside the moa after the Maori showed up, although to the best of my knowledge there is no Maori memory of small important prey animals. Incidentally, this is another reason why the Holocene New Zealand extinctions were not ‘megafaunal’ as people often assume, as most of the impacted avifauna on New Zealand were actually small species representing the opposite pattern to the earlier Pleistocene extinctions in North America. Probably all of these extinct birds were k-selected and not equipped to defend their nests against ground predators, so I’m sure my point about New Zealand being too unusual to draw many informative comparisons about the American megafauna still stands.

  11. I’m having trouble making long replies here,they don’t get through and I’m told I’m double posting when I send, notice my comment doesn’t show up, and then send again.

  12. dearieme says:

    The thing to understand about the Maori is that the subtropical agriculture that they brought to temperate NZ failed there. Their chickens and pigs died out,and their crops failed except for the sweet potato. They survived by hunting, fishing and cannibalism. Those were grim times. Consequently the Moa were doomed.

    • The fourth doorman of the apocalypse says:

      Most of NZ is further south than any point on Mainland Australia and some of it is even further south than Tasmania.

      It gets very cold in NZ during the winter.

    • Yes, completely unlike the Clovis in North America who had other food animals available (their primary prey was bison), and who had appeared in situ from the Buttermilk complex demonstrating a period of prior coexistence with megafauna as opposed to a sudden migration of the Clovis people into the Americas.

      Though it is only to be expected that a technological shift have an ecological impact, the Clovis people were generalists who seem to have had relatively little impact upon dangerous megafauna when safer and more numerous prey were available. In particular the intelligence of proboscideans makes me extremely sceptical that they were incapable of adapting in a short period of time to low-levels of predation by stone age humans and the impact of hunting (or a specific hunting technique) on any species of megafauna must have been different to that on dissimilar species of megafauna.

      Yet the overkill hypothesis assumes that the impact of humans on dissimilar species must have been the same because they disappear at around the same time – and how close in time? This is the problem with applying Ockham’s razor before going into the details to build up the larger picture by gathering specifics.

  13. pig ig'rant says:

    Dr. Cochran do you have any explanation for why thease people are so resistant to the idea of over hunting? Is it a case of spout climate change and watch the grant money roll in?

    • ziel says:

      I don’t think it’s climate change. Like the commenter here “bones and behaviors” seems to feel, there’s a sacred belief that indigenous peoples are careful stewards of the earth, and that environmental destruction is an invention of modern, Western men. Thus complex explanations for paleo- extinctions are needed .

      • I agree, but it always seemed backwards to me. I’d rather lay claim to ancestors who successfully exploited difficult environments and fed the kids than ones who made ecological pronouncements suitable for daily inspiration calendars. “The earth does not belong to us. We belong to the earth.” My ancestors said odd things about Total Depravity that seem to have held up better.

        I’m guessing that native peoples, having survived bad times and all, had rules to live by of a somewhat more practical nature.

  14. dave chamberlin says:

    The supposed experts are still arguing that climate or disease rather than man finished off various large tasty critters in multiple locations. I have no idea why they keep making excuses instead of just admitting the simple truth that island after island and continent after continent when modern man got there a high percentage of the mega fauna quickly went extinct. They behave as if ignorant public opinion counts as much or more than scientific evidence.

    Well, sadly, it often does. We can scoff at the creationists denying evolution but then we many other areas of discussion where the “experts” whore themselves to appease public opinion. It is exactly why blogs like this one are needed.

  15. Anonymous says:

    “Having other alternate prey animals makes pushing a given species to extinction more likely, not less. Think it through.” No thinking it through already? OK, it’s something like this: trash on shores is dangerous for the birds nesting there, otherwise they (the shores) wouldn’t be worth a wolverine’s visit. As for megafaunas, the really interesting thing is the persistence of some. Perhaps big animals in some places got adapted to humans. I wonder if the survival of many big animals in tropical and temperate Asia is due to adapting to Homo erectus, and thus becoming somewhat pre-adapted to sapiens. Even in Europe and the Levant, some big animals that had survived the Neanderthals made it to historical times, and some would even have gone extinct only very recently if people didn’t finally become worried.

    • The fourth doorman of the apocalypse says:

      There is an island off South Australia called Kangaroo Island.

      When the seas rose there were no Aborigines there, or they died out and never figured out how to bridge the several mile gap to the island.

      There were, however, lots of kangaroos. When European explorers first arrived, the kangaroos were unafraid of humans and quite a few ended up in cooking pots. These days they are very wary of humans.

      There will always be natural variance in any behavioral trait, like wariness of big animals you have never seen before. Over the years when their presence is lacking those with high levels of wariness will become fewer in number (because those brain areas are expensive to maintain or could be devoted to other things.) and so eventually, the majority of the population will be unwary and easily caught, especially when there is no other predator.

      After the introduction of large predator species, selection will operate in the other direction, and, if their generation time is short enough, the species might survive.

      If Aborigines had managed to get to that island, I suspect the kangaroos on Kangaroo Island would have been hunted to extinction.

      • Sandgroper says:

        For small brained animals, kangaroos learn very quickly. In the cemetary where my father is buried, large greys are abundant, virging on ridiculous numbers, and they show no fear of people. They eat the flowers placed on the graves. In farming areas, they are much more wary of humans, and a human carrying even a very small rifle like my single shot 22 calibre is treated with extreme caution.

      • Sandgroper says:

        An equally likely probability is that dingoes never made it to Kangaroo Island.

      • Richard Sharpe says:


        Near where I work there are some ponds. During the spring there were several groups of ducklings that hatched.

        When in the water foraging the ducklings showed very different behaviors to the arrival of dogs or humans at the water’s edge than their mothers did. The ducklings would churn their legs and almost walk across the water away from the large thing that presented itself, while the mothers would hardly move and would interpose themselves between the ducklings and the intruder.

        It seems unlikely that the ducklings learned this behavior from their mothers or other ducklings. Each group of ducklings tended to stay away from other groups of ducklings.

    • There were Pleistocene extinctions in southeast Asia, but they are quite clearly linked to shifting climate and sea levels. For example the extinction of Asian hippos was caused by rising sea levels submerging the habitable rivers that were available for them. Although there is extant megafauna in Asia it is nonetheless described as ‘depauperate’ relative to that of the Pleistocene.

      It is because southeast Asia suffered important megafaunal extinctions despite its extremely long period of human occupation and lack of hunting points in the Pleistocene of that region’s archaeological record that it gets overlooked by overkill hypothesists…

  16. Steve Sailer says:

    The Ice Age megafauna were killed off by the climate getting warmer … or colder. Either explanation seems to serve. Why megafauna couldn’t adjust to changing temperature by walking north or south remains unexplained.

    • Sandgroper says:

      They did survive several periods of climate change in Australia, then after humans arrived, the next climate change killed ’em. Then when humans entered Tasmania, the same thing happened – the next climate change did what the previous ones couldn’t, and extincted them. Massive coincidence.

      If Bones is so confident of the conservation intelligence of humans, maybe he can explain why they cut down every last tree on Easter Island.

      • Sandgroper says:

        …not to mention the species extinctions in the Hawaiian islands, and everywhere else in the Pacific after the arrival of humans.

      • There is no need for me to explain the destructive impact of humans upon atypical insular ecosystems. The issue is how much can be inferred about human impacts upon continental faunas and ecosystems from such extreme cases. the only similarity I can see is that species actually went extinct and that a k-selected reproductive strategy put certain species at increased risk. Since the patterns of the extinctions were completely different on islands than on continents the overkill hypothesis rests on surprisingly weak assumptions and questionable inferences.

  17. Anonymous says:

    If you’re an adult really huge herbivore in a man-free environment, being much concerned with anything our size would have been counterproductive. I bet many a mammoth was completely surprised to get attacked by these squeaking, branch-carrying critters. And a healthy, Loxodonta-like attitude towards humans wouldn’t have time to evolve on australopitheci growing bigger and bolder and exploring their limits. As for the poor moas, they must have been as innately unable to worry about anything walking as the sea iguana. But the smaller flightless birds wouldn’t have to be particularly K-selected, just being flightless would do the trick.

  18. Georgia Resident says:

    Just thinking out loud here, but it would seem, all other things being equal, that it would be more likely that humans would hunt continental-range species to extinction than species on small, isolated islands. Here’s why:
    On an isolated island, the human population would probably be small enough that they could coordinate efforts at conservation. If everyone was of a single tribe, they would be more likely to see overhunting as a collective issue. Presumably, they would view the animals as a common resource, and impose restrictions on their members to prevent overhunting. And the islands would keep the animals from wandering into some other tribe’s territory, and reduce the risk of some other tribe poaching on the conservationists’ territory.
    By contrast, on an open range like, for example, the Great Plains of North America, it would be much harder for a single tribe to manage game and prevent overhunting, because their game stocks could wander into the territory of other tribes, and other tribes would have more opportunity to poach on a conservationist tribe’s territory. Essentially, the pool of tribes that could potentially access this common resource (game stocks) would be much larger, and therefore much more likely to create a “Tragedy of the Commons”-type situation.

  19. There are a couple of problems with your logic. First of all while it is quite possible the impact did not occur, there are multiple lines of evidence now (nanodiamonds by Andrew Madden’s group, a platinum spike in the Greenland ice core, and the impact spherules), and get this, there is an actual crater, Corossol in the Gulf of St. Lawrence. Also, there is the possibility of a northern hemisphere ozone collapse associated with any large impact onto ice and water. So you see, your logic is on extremely shaky ground. If there is any truth to what you say its accidental.

  20. JayMan says:

    And now….

    “To think of scattered populations of Ice Age people with primitive technology driving huge animals to extinction, to me is almost silly,” said Grant Zazula, chief paleontologist for the Yukon Territory and the study’s lead author.


    Mastodons weren’t hunted to extinction by Ice Age humans — they simply froze to death, new study finds | National Post

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