Megafaunal Extinctions

When competent human hunters encountered naive fauna, the biggest animals,  things like mammoths and toxodons and diprotodons, all went extinct.  It is not hard to see why this occurred. Large animals are more worth hunting than rabbits, and easier to catch, while having a far lower reproductive rate.  Moreover, humans are not naturally narrow specialists on any one species, so are not limited by the abundance of that species in the way that the lynx population depends on the hare population. Being omnivores, they could manage even when the megafauna as a whole were becoming rare.

There were subtle factors at work as well: the first human colonists in a new land probably didn’t develop ethnic/language splits for some time, which meant that the no-mans-land zones between tribes that can act as natural game preserves didn’t exist in that crucial early period. Such game preserves might have allowed the megafauna to evolve better defenses against humans – but they never got the chance.

It happened in the Americas, in Australia, in New Zealand, in Madagascar, and in sundry islands. There is no reason to think that climate had much to do with it, except in the sense that climatic change may sometimes have helped open up a path to those virgin lands in which the hand of man had never set foot, via melting glaciers or low sea level.

I don’t know the numbers, but certainly a large fraction of archeologists and paleontologists, perhaps a majority,  don’t believe that human hunters were responsible, or believe that hunting was only one of several factors.  Donald Grayson and David Meltzer, for example. Why do they think this?   In part I think it is an aversion to simple explanations, a reversal of Ockham’s razor, which is common in these fields. Of course then I have to explain why they would do such a silly thing, and I can’t.  Probably some  with these opinions are specialists in a particular geographic area, and do not appreciate the power of looking at multiple extinction events:  it’s pretty hard to argue that the climate just happened to change whenever people showed when it happens five or six times.

It might be that belief in specialization is even more of a problem than specialization itself.  Lots of time you have to gather insights and information from several fields to make progress on a puzzle.  It seems to me that many researchers aren’t willing to learn much outside their field, even when it’s the only route to the answer.  But then, maybe they can’t.   I remember an anthropologist who could believe in humans rapidly filling up New Zealand, which is about the size of Colorado, but just couldn’t see how they could have managed to fill up a whole continent in a couple of thousand years.  Evidently she didn’t understand geometric growth.  She is not alone.  I have see anthropologists argue  [The revolution that wasn’t] that increased human density in ancient Africa was driven by the continent ‘finally getting full’, rather than increased intellectual abilities and resulting greater technological sophistication.  That’s truly silly. Look, back in those days, technology changed slowly: you would hardly notice significant change over 50k years.  Human populations grow far faster than that, given the chance.   Imagine a population with three surviving children per couple, which is nothing special: it would grow by a factor of ten million in a thousand years.  The average long-term growth rate was very low, but that is because the rate of increase in human capabilities, which determine the carrying capacity, was very slow – not because rapid population growth is difficult or impossible.

I could explain this to my 11-year old twins in five minutes, but I don’t know that I could ever explain it to Brooks and McBrearty.

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44 Responses to Megafaunal Extinctions

  1. Matt says:

    http://www.youtube.com/watch?feature=player_embedded&v=0htZz-mHvuw
    Eske Willerslev at the 2012 DOE JGI Genomics of Energy and Environment Meeting. He starts with a discussion of the late quarternary megafauna extinctions (and goes on to other interesting stuff).

    “In some cases, climate seems to be the only … driver of extinction, for example, Musk-Ox…. They simply don’t meet humans”… They just don’t meet each other”.

    “Other animals seem to definitely be massively impacted by humans, things like the Bison, Horse, where we can see that as soon as humans enter to their area, thats when things are really going wrong and we can see a massive amount of the bones in the archaeological record”.

    http://www.nature.com/nature/journal/v479/n7373/full/nature10574.html – Species-specific responses of Late Quaternary megafauna to climate and humans

    “Each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment.

    Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse.

    We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, emphasizing the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.”

  2. bob sykes says:

    The problem is anthropology, like all the social sciences (including economics and history), is a pseudoscience and the natural home to lazy charlatans.

  3. dearieme says:

    Suppose humans kill off species A. Then the other predators of Species A turn their attention to species B and wipe it out. It might be that Species B and humans never met, but humans are nevertheless responsible for its extinction. Or perhaps it was subtler: the extinction of Species A altered the nature of the grazing and led to the extinction of B. Et bloody cetera. You’d have to seriously lack an imagination to simply point at climate change and say “It must have been that because I can’t think of any other cause”.

    • Matt says:

      Them not meeting falsifies the simple explanation that humans basically killed them, for food.

      Them not meeting, true, doesn’t falsify the idea that some complicated, unfalsifiable because it isn’t defined at all causal ecological chain that is somehow involves humans was responsible.

      I’d think, though, you’d have to seriously lack an imagination to simply point at humans and say “It must have been humans wot did it even though I can’t say how” (and maybe a bit of a fixation on man as prime mover).

    • doug1111 says:

      The two main reason why anthropologists point to climate change is that 1) climate change is a popular and more than semi religious cause of the leftist elite; and 2) they have a gut level desire to promote the notion of nobler “savages”, that is hunter gatherer non white man.

      • gcochran9 says:

        You need to know quite about people and their situation in order to make a decent guess as to their motivations. Or you could just bloviate.

        Someone who thinks that there is a big climatic difference between an ice age and contemporary weather is not crazy, because there IS a big difference. I’ve been in Chicago, plenty of times: I think that things were significantly different when it was covered with 3000 feet of ice.

        The problem is that there have been a number of ice ages, a number of glacial advances and retreats, and the earlier cycles did not knock off most of the big animals in North America. And of course the megafauna went extinct in other places where we know that there was no rapid climate change, but where humans had just arrived.

        I have wondered if some sort of noble savage idea was part of the reason for North American archeologists’ resistance to overhunting explanations of the megafaunal extinctions – so I asked around, rather than pretending that I knew what was going on in their pointy heads. It appears that they are more likely to think that Amerindians just weren’t good enough hunters to wipe anything out, which is, as far as I can see, just stupid.

        Some can’t understand that a human population can easily expand to fill a continent within a millennium – they can’t understand exponential growth, which is also stupid.
        I wouldn’t rule out some amount of dusky noble savage ideology as a driver, but it doesn’t look to be the main factor.

        By the way, if you have a good knowledge of radiative transfer and cloud physics and simulation development,. etc etc – and have spent a couple of years checking out the validity of climate simulation models, your thoughts on global warming are welcome. But, on the other hand, you’re going to parrot crap generated by a bunch of dishonest right-wing morons who couldn’t integrate x ln(x) , they are not welcome.

      • doug1111 says:

        I take your points about there having been very significant naturally occurring climate changes between cold ice ages and warm periods, but in many of them the N A megafauna didn’t die out.

        The best thing I’ve seen putting anthropomorphic climate change claims into perspective is this lecture by science writer Matt Ridley, who wrote the Red Queen. In a nutshell he thinks some has been and will continue to occur but not at the really alarming rate the alarmists claim and predict.

        http://www.bishop-hill.net/storage/ScientificHeresy.pdf

  4. dave chamberlin says:

    There is a third factor outside of humans and climate that contributed to mass extinctions that is substantiated by history. When long seperated land masses rejoin similar but species intermingle and typically the animals from the smaller landmass lose out. There is more to it than that, ecology is a complex subject, but it stands to reason the larger land mass holds the larger gene pool that has reacted over time differently to a wider variety of pathogens and parasites. When South and North America recombined three nillion years ago a whole lot more species in South America went extinct than in North America. We don’t have to look further than our own species to see the result of what happened to native americans after 1491. I don’t think climate had a damn thing to do with magafauna extinctions in the Americas, all it would have done in the last ace age is what it did in all the preceeding ice ages, push the existing species into smaller areas. But when similar species long seperated on the asian and american land masses remingled the result would have resulted in winners and losers. We actually have some indication of that, herbivores started a radical decline in North America 15,000 years before present, this is before man left his tell tale signs, cut marks on bones and stone tools Fagan and others point to this as proof that climate is in part to blame, I don’t buy it and I have yet to read any explanation as to why the climate variations during the key time of extinctions in the americas. was any different than earlier ice ages.

    Seperately I would like to illustrate how archeologists could venture outside of their field and learn. If you want to learn about ice age man hunting you talk to hunters. Book smart acedemics have a hard time believing a small group of hunter gatherers could reek such ecological damage as they did. How today do you hunt a cougar? What is the most important thing to bring along. 99% of couch potatoes are going to say a good hunting rifle. Guess what, you would be wrong. You need a good hunting dog, better yet a group of hunting dogs, to follow the scent trail of a cougar and follow it untill it is exhausted and hides up in a tree. A cougar has senses and speed vastly superior to us and will easily elude hunters with guns. The cougar population on americas west coast has exploded since hunting them with dogs was made illegal. From there you begin to form a picture of just how formidable ice age hunters following the scent trail of their chosen prey could be. What could get away, who would win every time an exhausted animal was encircled. I don’t believe archeologists are lazy charletans. But as a general rule when reading what they have to say about ancient man I always consider pre modern man to smarter than they project them to be and the archeologists to be dumber than they project themselves to be.

  5. baloocartoons says:

    Very enlightening. I’ve discussed this with an appropriate illustration and linked to it here:

    http://ex-army.blogspot.com/2012/05/extinction-and-people.html

  6. Steve Sailer says:

    How about people and their dogs bringing new diseases to the New World?

    • gcochran9 says:

      I think there’s little chance of that – at least, that such new diseases caused extinctions. First, we don’t know of many cases of infectious diseases causing extinctions. Second, early Amerindians came through the Arctic, in small bands: not a favorable scenario for crowd or vector-carried diseases. Third, such a disease would have had to hit a very wide range of species – everything from giant tortoises to mammoths. Again, unlikely.

      • dave chamberlin says:

        You have convinced me that disease introduction can cause population collapse but rarely if ever extinction. Thinking about it further there is a big difference when continents are seperated for ice age cycles (50,000 years or more) like Asia and North America and continents that are seperated by wide bodies of water for tens of millions of year, like Australia and Asia. When mammals occupying the same ecological niche as marsupials are introduced onto the marsupials land mass, this happened in South America three million years ago and in recent times in Australia than mass extinction occurs. So I correct my earlier statement that the intermingling of Asian and North American land animals could have contributed to the mass extinction event. That leaves man and man alone as the culprit.

      • Anthony says:

        Relatedly – the evidence that there was a population collapse among native Americans after 1492 caused by European and African diseases is pretty strong now. Was there any similar event, or evidence of epidemic disease, after the European contacts of ca. 1000?

  7. it’s pretty hard to argue that the climate just happened to change whenever people showed when it happens five or six times.
    Don’t you know that only whites are bad, and that all other races lived in peace and harmony with nature until the horrible evil white folk showed up.

    Not only did those wise native people live in harmony with nature, they also did not eat each other, nor commit mass murder and genocide. The peaceloving Aztecs only committed just a teensy weensly little bit of human sacrifice, and it is a horrid racist calumny by horrid racists to suggest that they ate the people they sacrificed, and that Aztecs lived largely on human flesh.

    Aren’s in “The Man Eating Myth” assures us that Bernal Díaz del Castillo gives us only five reports, of cannibalism, none of them first hand, and none of them suggestive of widespread routine cannibalism. If one opens up Diaz’s book, Diaz reports cannibalism all the time everywhere, as widespread and routine among the elite as europeans eating bacon. Since Diaz contradicts Arens, and Diaz is an evil conquistador, while Arens is a good progressive, obviously Diaz is lying in his book, so that all the places in his book where he encounters routine everyday cannibalism are lies, so Arens was right not to count them.

  8. Steve Sailer says:

    The notion that global warming wiped out, say, the wooly mammoths is pretty silly. At the Page Museum at the La Brea Tarpits, it says that the climate on Wilshire Blvd. before the big die-off was about what the climate is now on the Monterey Peninsula 300 miles to the north. Well, wooly mammoths were quite capable of walking 300 miles north or, for that matter, 6000 feet up into mountains surrounding Los Angeles.

  9. Jehu says:

    Along Dave’s line of thought, should you ever be desperate and in need of game, never say that the government never did anything for you.
    Take a copy of the hunting regulations for your state. Look up all the hunting methods and tactics that are banned.
    Those are the ones that your lower tech ancestors would have used. They’re banned precisely because of their effectiveness and efficiency.

    • dave chamberlin says:

      Your comment got me thinking about which banned hunting methods would have had the largest payoff. It is more than just an interesting thought experiment, it could lead to testable hypothesis down the road. Having recently read Richard Wrangham’s book “Catching Fire, How cooking Made Us Human” he lays out some pretty persuasive reasons why way back yonder 1.8 million years ago Homo Erectus evolved a radically smaller digestive tract in response to food being cooked and tenderized. I won’t run off speculating on that as it is completely off the thread topic but fire lead to an amazingly effective and banned hunting method still used by american indians because they are the only ones in the USA allowed to use it. Fish are damned tasty and also damned stupid, they have never learned that swimming up to a bright light during night time frequently gets them caught on the end of a spear. Fisherman are pissed off that american indians are still allowed to go fishing this way because it is so easy and so effective. Sharpening a stick with a knife (or a piece of flint if you want to be historically accurate) it is really easy to incomplete a cut that leaves a perfect barb near the point that would keep a fish from sliding off the spear. Fire made food far more digestable, but it also kept us warm, protected us at night, and made fish so easy to catch it’s now considered cheating. No wonder Homo Erectus spread out far beyond Africa.

  10. Tschafer says:

    With regard to Global Warming, GC’s point is well taken, but it should however be noted that most of those pushing the idea of catastrophic global warming, i.e. George Monbiot, Al Gore, etc, have no understanding of radiative hear transfer, albedo, or atmospheric dynamics either, and a lot of people who do understand these things have their doubts (Bruce Lindzen and Jerry Pournelle, to name two), and that such things as dishonest left-wing morons also exist, are in fact quite common. By the way, this is how we know that AGW has become a political, rather than a scientific issue – people who have no opinion about string theory or non-linear dynamics have an opinion on climate change.

    • gcochran9 says:

      Lindzen probably has a right to an opinion: Jerry Pournelle does not. He is no kind of physicist. Yet he has an opinion anyway, and goes on and on and on about it. I used to occasionally check his arguments: to the extent that I could check them, they were always wrong.

      This is not a subject that interests me very much. For one thing, the world is never going to do much about in any event, regardless of the facts, so it’s moot.

      Of the people who do work in the field and thus know something about it, almost all think there’s a problem. The notion that that a noticeable percentage of knowledgeable people disagree with it is not true.

      Left-wingers say that they believe the scientists: probably many of them also find the whole notion attractive. Right-wingers disbelieve in it because it’s now a mark of their tribal membership: what they have to say about it is almost always false. And there are of course paid shills involved – all on the right wing side. Just as there were for cigarettes – a few of them even the same people.

      However, just because the lying bloodsuckers at the editorial page of the Wall Street Journal oppose an idea doesn’t automatically mean that it is correct. Personally, and I say this without having invested the time required to have a valid opinion, I have my doubts about the predictive validity of the required simulation models, particularly since all the projections of big effects involve complex feedback. It is hard to create valid models of such phenomena. We can project planetary positions millions of years into the future, but this is not like that.

      • Tschafer says:

        “Of the people who do work in the field and thus know something about it, almost all think there’s a problem” – agreed, but there are pretty big disagreements as to how big a problem, and how urgent it is to act ASAP, especially on the basis of models that may not be all that accurate. As for all the paid shills being on the right-wing side, I suppose it depends on what you consider to be a paid shill. And I have to say, I’m kind of surprised at your harsh words for Jerry Pournelle – he speaks very highly of you. Like you, I’m not all that interested in this topic, but it is interesting that so many people hve such pronounced opinions on what is, after all, a fairly esoteric piece of atmospheric physics.

        • gcochran9 says:

          Jerry has a Ph.D. in psychology and political science: I wasn’t saying that he was a bad physicist, just not one at all. I have know him for a long time, and we do agree on some things, but I have argued with him for years and years. I didn’t enjoy his repeated arguments about how people should listen to, or at least consider, Duesberg’s arguments about AIDS. I thought that they were obviously insane tripe – and they were. I got tired of having to explain obvious things about CFCs – like, for example, that although they have high molecular weight, they can still easily get into the stratosphere, the same way that thunderheads do. I got tired of pointing out that his position on education – that it’s gone to the dogs, that back in his day everyone could read and write – was totally false. Primary and secondary education are if anything a bit more effective than they used to be, although needlessly expensive – it’s the students that are worse. Demographic changes. Dumber, on average. I even bothered to look up the illiteracy rates for his home county in the census: 8% couldn’t read their names, in the decade before his birth….

          I’m tired of explaining that Greenland was hardly green, even during the medieval climactic optimum: it was really marginal for a Norse dairy-farming culture, right on the ragged edge of habitable. Sheesh, even the saga says explicitly that the name Greenland was chosen as a real-estate promotion by Eric the Red.

          There are probably 50 issues that I have argued with Jerry over the years – usually repeatedly – that I see him as been hopelessly, mulishly wrong about. That’s my version of being simpatico, I guess.

  11. j says:

    “… Amerindians just weren’t good enough hunters to wipe anything out…”

    In Argentina, extensive grasslands (the pampas) were empty of herbivores when the Spaniards arrived in the 1550. Yet by 1650 the pampas were fullly colonized by a few escaped cows and horses. If the Indians were so effective in hunting big herbivores, those enormous savage herds could not exist for long, yet they prospered till modernity. Also North American buffalo herds survived Indian hunting without much problems.

  12. > I’m tired of explaining that Greenland was hardly green, even during the medieval climactic optimum: it was really marginal for a Norse dairy-farming culture,

    As the glaciers thaw, they reveal Norse homesteads under them.

    So Greenland was, if not green, a lot greener that it was today.

    I have read the climategate files, and you, obviously, have not.

    It is apparent on reading these files that most climate scientists know nothing about science and care less. Except for Briffa, most of the scientists featured in those documents appear to have graduated in politics, rather than science, whatever the nominal topic in which they supposedly graduated.

    Every single email in the thousand or so emails smells bad, some smell worse than others, but they are all pretty much the same.

    The most famous email is of course “Mike’s nature trick … to hide the decline”, though they are all much the same, the whole thousand of them, though not so wonderfully self summarizing.

    Were I to challenge you to explain that email you would patronizingly explain that “decline” does not necessarily mean what it sounds like it means, implicitly admitting that “trick” and “hide” mean exactly what they sound like they mean: That, as in most of the emails, the climate scientists are hiding stuff from us in order to trick us.

    • gcochran9 says:

      You could be tricked by a sheep. Banned.

      • Tschafer says:

        With all due respect, that’s not much of a refutation.

        • gcochran9 says:

          There are more people wrong on the internet than there are seconds in my day. Anyone who thinks that that use of the word ‘trick’ means ‘deception’ is hopeless. It refers to some clever technique for solving a problem, like completing the square or assuming scale invariance in a phase transition problem. I remember when my mother was taken aback at some unfamiliar physics jargon: she saw the title of a paper about magnetic degenerate white dwarfs. But she didn’t insist that this truly revealed just how decadent our physics department was: I explained, and she laughed. Because she was the opposite of an idiot, while McDonald is the very avatar of motivated stupidity.

          Greenland. I know something about Greenland. It has an area of > 830,000 square miles, almost all barren rock and ice. The only green spots are found at the heads of few of the deep fjords on the southwest – green enough to grow grass. Too cold & too short a growing season to raise any grain crop. The Norse settlers, maybe 5000 of them at peak, had about 600 farms, averaging maybe 400 acres each, for a total of less than 400 useful square miles out of those 830000. About the size of my home county: but far less productive. Assuming population breakeven, those Norse required about 100 acres to sustain one person. Considering that they either grazed sheep or raised hay for cattle, in a truly crummy area with poor soils and a short growing season, this is not so unreasonable. In my home county, about the same size, you routinely get over 200 bushels of corn per acre. You could grow enough to keep someone fed out of a third of an acre, probably less: we’re talking >300 times more productive than Norse Greenland. Some of that is of course due to modern hybrids, fertilizer, etc – but Greenland was not farmer heaven.

          Less than 400 useful square miles during the medieval climate optimum, which probably average 1 degree Celsius higher than 1950. Later, in the little ice age, they probably averaged 1 degree colder than the 1950 average. Life became hard, and a lot of other things went wrong. Colony eventually collapsed, exact details unknown.

          Does this show that the world has not warmed since the year 1000? No: it shows Greenland is about the same now as it was then. You would have to look at various kinds of global data to get any idea on the overall change. Why do people act as if a slightly more habitable Greenland a millennium ago somehow disproves the statement that the world as a whole was cooler then than now? Motivated reasoning: they want a certain conclusion real bad. At this point it’s become an identifying tribal marker, like left-wingers believing in the innocence of Alger Hiss. And of course they’re mostly just repeating nonsense that some flack dreamed up. Many of the same people will mouth drivel about how a Finn and a Zulu could easily be genetically closer two each other than to other co-ethnics, which is never, ever, true.

          When you think about it, falsehoods, stupid crap, make the best group identifiers, because anyone might agree with you when you’re obviously right. Signing up to clear nonsense is a better test of group loyalty. A true friend is with you when you’re wrong. Ideally, not just wrong, but barking mad, rolling around in your own vomit wrong. Movement conservatives have learned this lesson well.

  13. RS says:

    –The American bison is a relative newcomer to North America, having originated in Eurasia and migrated over the Bering Strait.[39] About 10,000 years ago it replaced the steppe bison (Bison priscus), a previous immigrant that was much larger. It is thought that the long-horned bison[vague] became extinct due to a changing ecosystem and hunting pressure following the development of the Clovis point and related technology, and improved hunting skills. During this same period, other megafauna vanished and were replaced to some degree by immigrant Eurasian animals that were better adapted to predatory humans.

    –“Hernando De Soto’s expedition staggered through the Southeast for four years in the early 16th century and saw hordes of people but apparently did not see a single bison,” Charles C. Mann wrote in 1491: New Revelations of the Americas Before Columbus. Mann discussed the evidence that Native Americans not only created (by selective use of fire) the large grasslands that provided the bison’s ideal habitat but also kept the bison population regulated. In this theory, it was only when the original human population was devastated by wave after wave of epidemic (from diseases of Europeans) after the 16th century that the bison herds propagated wildly. In such a view, the seas of bison herds that stretched to the horizon were a symptom of an ecology out of balance, only rendered possible by decades of heavier-than-average rainfall.

    Got it, the Indians drowned because they were trampled en masse by bison dying of smallpox, resulting in heavy rainfall.

    How exactly would an anthropogenic surfeit of ideal habitat ‘regulate’ the bison population, and why would Indians regulate rather than maximize the conversion of grass –> bison? I’m going to go out on a limb and guess that the Indians had more likely ‘regulated’ bison by eating them.

    Other evidence of the arrival circa 1550–1600 AD in the savannas of the eastern seaboard includes the lack of places which southeast natives named after buffalo.

    So, I guess they expanded to the Southeast shortly after the 1539-41 de Soto expedition. As I recall, de Soto found lots of depopulate habitations in addition to the above mentioned ‘hordes of people’. So Indian population contraction was probably well underway, as one would expect — and ongoing, I presume.

    –What is not disputed is that before the introduction of horses, bison were herded into large chutes made of rocks and willow branches and then stampeded over cliffs. These buffalo jumps are found in several places in the U.S. and Canada, such as Head-Smashed-In Buffalo Jump.

    This must be one of those unsporting methods.<

  14. call says:

    –The American bison is a relative newcomer to North America, having originated in Eurasia and migrated over the Bering Strait.[39] About 10,000 years ago it replaced the steppe bison (Bison priscus), a previous immigrant that was much larger. It is thought that the long-horned bison[vague] became extinct due to a changing ecosystem and hunting pressure following the development of the Clovis point and related technology, and improved hunting skills. During this same period, other megafauna vanished and were replaced to some degree by immigrant Eurasian animals that were better adapted to predatory humans.

    –“Hernando De Soto’s expedition staggered through the Southeast for four years in the early 16th century and saw hordes of people but apparently did not see a single bison,” Charles C. Mann wrote in 1491: New Revelations of the Americas Before Columbus. Mann discussed the evidence that Native Americans not only created (by selective use of fire) the large grasslands that provided the bison’s ideal habitat but also kept the bison population regulated. In this theory, it was only when the original human population was devastated by wave after wave of epidemic (from diseases of Europeans) after the 16th century that the bison herds propagated wildly. In such a view, the seas of bison herds that stretched to the horizon were a symptom of an ecology out of balance, only rendered possible by decades of heavier-than-average rainfall.

    Got it, the Indians drowned because they were trampled en masse by bison dying of smallpox, resulting in heavy rainfall.

    How exactly would an anthropogenic surfeit of ideal habitat ‘regulate’ the bison population, and why would Indians regulate rather than maximize the conversion of grass –> bison? I’m going to go out on a limb and guess that the Indians had more likely ‘regulated’ bison by eating them.

    Other evidence of the arrival circa 1550–1600 AD in the savannas of the eastern seaboard includes the lack of places which southeast natives named after buffalo.

    So, I guess they expanded to the Southeast shortly after the 1539-41 de Soto expedition. As I recall, de Soto found lots of depopulate habitations in addition to the above mentioned ‘hordes of people’. So Indian population contraction was probably well underway, as one would expect — and ongoing, I presume.

    –What is not disputed is that before the introduction of horses, bison were herded into large chutes made of rocks and willow branches and then stampeded over cliffs. These buffalo jumps are found in several places in the U.S. and Canada, such as Head-Smashed-In Buffalo Jump.

    This must be one of those unsporting methods.[

  15. ironrailsironweights says:

    I’ve become skeptical about the concept of prehistoric humans hunting megafauna into extinction after seeing this helmet-cam video (caution: somewhat bloody) of a man hunting wild boar in California. Boars are fierce but hardly megafauna. It just doesn’t seem likely that prehistoric humans would have hunted megafauna with stone-tipped spears and arrows unless they were truly desperate and no smaller, safer game was available.

    • gcochran9 says:

      You make an interesting counterexample to the notion that all living humans are behaviorally modern.

    • call says:

      I hardy doubt that it was perilous in many cases. That doesn’t mean they didn’t do it. Fellow men are damnably dangerous to fight with as well, which doesn’t mean Indians etc didn’t have wars or intra-group combats.

      Malthus-like logic doesn’t apply only to agriculture. Safe game species, whether meso, micro or mega, may not be very abundant at equilibrium. Wasting energy, missing out on chances for status jockeying, and so on can be just as dangerous to one’s fitness as actual danger. Also, accepting danger from beasts and warriors does have crucial side-benefits that are less than obvious — mainly, it intimidates other men, resulting in high status.

      Granted, all that doesn’t mean there is no kind of beast that’s too dangerous to be fitness-profitable to attack. There could be such a one. I don’t know what the state of opinion is in the field, but I’m assuming some of the great carnivores of the Americas were extinguished by competition with humans, and perhaps by harassing activity of humans, and not primarily by determined human attacks on adults. For example, I could imagine humans might attack unguarded dens of lions to kill cubs.

    • Hereward says:

      Africans hunted elephants with spears into the 20th Century – it may have been dangerous, but they’re high-payoff game. At any rate, danger can be part of the appeal of hunting. Aside from thrills, one acquires status as a brave man. Europeans hunted wild boar with spears into the modern period. Some Iberian showoffs displayed their prowess by using daggers. It says something that quite a few small, safe game species survive in Europe and the Near East, while lions and aurochs do not.

    • Master Dogen says:

      Maybe you are missing the point about evolved behavioral defenses? Imagine a giant sloth that has never seen a human before and whose ancestors never saw a human. As a group of 20 of the weird little bipeds slowly fan out around the sloth, the sloth looks with mild disinterest and continues munching away on its palm frond lunch. Why would it show any concern about a creature that resembles no other predator it has ever seen?

      On the other hand, African elephants (and wild boars) evolved alongside humans. As proto-humans evolved one hunting behavior, the proto-elephants evolved human-distrusting instincts. Etc.

      I’m not actually schooled in any of this, of course. But that’s my rough understanding of why it would be so easy for the first ice-bridge Americans to wipe out so many megafauna species so rapidly. The ferocity of boars notwithstanding.

  16. j says:

    American SouthEast had no buffalo herds nor eatable animals (except may be field rats) when the Europeans arrived. The “Relaciones” (Reports) of Alvar Nuñez Cabeza de Vaca paint an ecological disaster area. Cabeza de Vaca was the second officer of the Narváez expedition, sent to occupy the mainland of North America. Within several months of their landing near Tampa Bay, Florida on April 15, 1528, he and three other men were the only survivors of the expedition party of 600 men. From his report one concludes that the natives barely survived harvesting water lily roots and prickly pears when available. No hunting is mentioned.

    May be the real question is not why the megafauna was exterminated, but why elephants survived in Africa. They should be dead by now.

    • call says:

      There are loads of deer and black bear there, to this day. As someone mentioned, the deer populations are not checked very severely by black bear, and in the absence of wolves they can be rather damaging to plant communities at browsing height (and to cars). When Europeans first arrived, wolves ranged to the coast.

      I’m guessing they are currently pretty well-checked by human hunters in some areas, but not others.

      The U.S. Department of Transportation estimates that white-tailed deer kill around 130 Americans each year simply by causing car accidents.

      I’m not sure how many lead diminished lives due to such accidents (severe pain, etc) — perhaps it’s something like 4x the # of deaths.

      There are about 1.5 million deer/vehicle collisions annually, resulting in 29,000 human injuries

      No doubt the majority of these injuries have no serious chronic result. But some do.

  17. JT56 says:

    I’m sorry but this is just absurd. There is no proof that humans preyed or even hunted a good majority of the megafauna of North/South America and Australia. The only reason why people or even scientists assume it was humans is the dates of humans arrival and the very few kill sites that has very few megafauna bones. No matter how much bitching people do the only reason why people want to think it was our ancestors fault is because of the recent extinctions of the past 600 years and the extinctions of the moa in New Zealand and a few large sloths that inhabited Madagascar. Everyone wants some type of justification for the megafauna demise but there is not a shred of proof that a populaton of a few thousand aboriginals with only rocks and primitive spears hunted every animal to extinction. It is also absurd that people think that primitive humans killed every creature that was bigger than them in N/S America within a thousand years or so. Like WTF are you talking about, yes humans killed a particular species like mammoths or mastodons and others but to say a population of 4-5 million people, man, woman, and child with an life expectancy of 35-40 years at best, generation after generation to kill off every living thing they see just for the fuck of it?! It is not even ethical nor is it even gullible to sit here and say that our ancestors were stupid. They must have known the probability to kill a giant creature and how successful they could or could not get the creature to go down. I apologize for the bickering but this grap needs to end, it was climate change, climate change, climate change. What proof to you have besides reading off an article that says they have evidence it was humans when most of it is pure speculation and in the end, until there is proof, it is just another hypothesis brought up with only claims that don’t even have proof to back up the claims.

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