The Extinct Ice Age Mammals of North America

The Extinct Ice Age Mammals of North America



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University of Washington Anthropology Professor Donald Grayson and recipient of the 2015 University Faculty Lecture Award delivers the University Faculty Lecture on April 28, 2016. Toward the end of the Ice Age, North America saw the extinction of an astonishing variety of often huge animals. Mammoths, mastodons, saber-toothed cats, lions, armadillos the size of small cars, sloths the size of elephants, beavers the size of bears, and many others were all gone by about 10,000 years ago. We do not know what caused these extinctions, but our knowledge of the Ice Age archaeology and paleontology of the deserts of western North America provides a novel opportunity to examine the common but contentious argument that people were behind all of them.

Donald K. Grayson, professor, Department of Anthropology, UW

04/2/2016

42 thoughts on “The Extinct Ice Age Mammals of North America”

  1. Hmm, I thought they found Clovis sites in the east. I remember something about a Clovis site on the eastern shore of Maryland and in Delaware.

  2. No proof of massive fires associated with the ET impact hypothesis?? I believe there is plenty of excavated proof. The Mammoths at 3700 and 8700 BP were NORTH and WEST of the majority of ice sheet source of melt water that would have caused the floods that contributed to the extinctions. Why not mention the younger dryas ice age and how suddenly it happened? Why not mention the scab lands and dry falls and the possibility that they were formed in one massive flood from the ET impact on the massive glaciers in canada?

  3. The distribution suggests that the lack of distribution over the northern part of North America is because the ice sheet scrubbed the land clean. The animals would have followed the edge of the ice as the ice sheet melted but met man at the end of the most recent glacial period. As for the argument that man was responsible for the demise of these animals, the survived cycle after cycle of glacial-interglacial periods. The only difference in our present Holocene interglacial is that man had arrived.

  4. There is so much wrong with this presentation, but I first want to thank the presenter for clearly and pleasantly sharing his thoughts (whatever their merits) and thereby allowing a serious discussion of this important topic. First, let me say that he omits very important extinctions and glosses over surprising survivors. But it is his general theses, namely, that (a) humans could not have been responsible for the collapse of the American megafauna, and (b) there cannot have been Africa-like herds of megafauna in Pleistocene North America, which must be refuted. The learned professor suffers from myopia in his attempts to view the ancient world. Humans, especially hunter-gatherer groups, are incredibly sophisticated hunters.

    The evidence of their hunting might not be great after thousands of years for a variety of reasons, including hunting methods that don't lend themselves to preservation (such as all-wood arrow shafts and tips as in New Guinea), cultural practice relating to butchering and disposal of game (do they just cut out the meat they can carry when game is plentiful or do they remove meat and bones?), and simply chance (how many evidences of hunting are preserved and how many of those are likely to be found by and correctly identified by paleontologists?).

    What few people realize is the simplicity that lies behind any mass extinction that doesn't affect all members of a faunal community (e.g. we lost mammoths, mastodons, gomphotheres, ground sloths, camels, horses, and tapirs in what is now the USA, but camels and tapirs survived in South America, and elephants (mammoths were just elephants) survived in much of Asia and most of Africa; also, Eurasia lost its muskoxen, but North America retained them). And here it is: more animals died than were born for long enough to ensure no more could be born.

    This sounds too obvious, right? But it's not, and greater minds have failed to grasp it. The animals which went extinct did not do so all at once. Yes, most seem to disappear by X date in North America or slightly later in South America, but, as pointed out in the presentation, there were seemingly random holdouts in other areas. All it would take for humans to be the proximal cause of the extinction of a species is for whatever pressures humans place on that species to be just enough more to cause a negative birthrate. When that happens and is sustained for centuries, animals which birth fewer young and whose young take longer to raise are doomed, but so are animals which might have an average amount of young for a larger animal but which live in already strained conditions (low densities due to competition with other animals, fragile environments, etc.). Think of the old saying about the straw that broke the camel's back. It comes from the reality that there will always be a tipping point: a camel's back can only sustain X amount of weight, and, in truth, it would be possible to cause a failure by placing that maximum amount of weight on the camel and then adding a single straw.

    If you look at extinctions around the world, you find that they do not correlate with unusual or even sever climate change. Muskoxen survived the end of the ice age just fine in the North American Arctic and in Siberia only to become extinct in Siberia thousands of years before the present. Elephants survived in China, Southeast Asia, South Asia, and parts of the Near East (in addition to virtually all of Africa) until the rise of Rome (more or less), but they were lost in Europe, the Americas, and northern Asia. However, if you focus on post-Pleistocene extinctions and extirpations, you can find a pattern: the elephants of Eurasia, which survived the transition to the Holocene, begin to disappear from the Chinese heartland the the Near East before the time of Christ. Some centuries later, the elephants of North Africa are gone. By the time of European colonialism, wild Asian elephants do no exist west of India or north of Nepal and South China and they are gone from populous Java. By the dawn of the 21st century, wild Asian elephants are virtually extinct in China, Vietnam, Cambodia, Laos, and are so fragmented in much of Indonesia, Burma, and India as to be nothing more than isolated genetic islands of wild elephants. In Africa, they are similarly fragmented; the bush elephant is almost completely confined to heavily managed game parks, and the forest elephant, though less managed, is vanishingly rare. Rhinos have fared worse. 3,000 years ago, they were found from the extreme west of the Indian subcontinent all the way to the Yangtze in China, and from the Yangtze all the way to Java. By 1,000 years ago, the three species of Asian rhino were gone from China and were contracting to the north and east within India. By 10 years ago, the Indian one-horned rhino numbers in the low thousands, the majority of which occupy a single park in India's extreme northwest; the lesser one-horned rhino (renamed the Javan rhino for the following reasons) had lost its last continental population of rhinos in the 2000s and was reduced to fewer than 100 individuals in the far west of Java; the Sumatran rhino, which, again, was actually once found from China to Indonesia, was similarly reduced to a tiny number of individuals, most in Sumatra, with little hope of surviving the century.

    As sad as it is to say, for all of our wonderful extant megafauna (three elephants and the rhinos of Africa and Asia), they have not birthed more offspring than the adults they've lost for at least the last 3,000 years. In other words, they are going extinct. They are functionally already extinct. We who are having this discussion just happen to be witnesses to the later stages of an extinction event that began thousands of years ago. If it can take 4,000 years to kill off the biggest game animals on the biggest land masses, how long would it take to do so on land masses which are much smaller? The answer, obviously, is less time would be needed. If, then, humans were the straw breaking the camels back in the Pleistocene, what difference might there be for game that had never been hunted by hominids versus game that knew humans as predators? Again, if you look at the distribution of extinction sin the Old World, you'll see that the areas where modern humans went first (Africa, the Near East, South and Southeast Asia) show fewer extinctions than areas where primates were newer members of the fauna (Europe, Siberia). When they crossed into North America, not a single game animal would have recognized them as predators. Hunting would have been dangerous only because of the other dangerous predators, which, no doubt, these first humans would have hunted aggressively for both defensive reasons and, likely, religious reasons. If they entered 15,000 years ago (a rounded number, but I think it's likely they arrived earlier than is generally accepted), all they would have to do is cause enough extra deaths each year for a a few thousand years, and all the megafauna would go extinct. Importantly, they needn't hunt any one animal much in order to accomplish this. If mammoths could only sustain a 10% mortality rate, and humans made it a 15% mortality rate, the mammoths would go extinct in a matter of centuries, but the vast majority of all mammoths right up to the end would die of natural causes.

    Because the above IS why the megafauna went extinct (and continue to do so), it will never be possible to prove. But we can infer this truth by looking at when megafauna have become extinction, which megafauna became extinct, and where they became extinct. Here's a summary:

    Mammoths and rhinos are extinct in Europe by the end of the Pleistocene.
    In North America, only three land herbivores of 750 lbs or more survive (elk, moose, bison); all others are extinct by the end of the Pleistocene EXCEPT the ground sloths of the Caribbean, which live on for thousands of years into the Holocene.
    In South America, no herbivores of more than 750 lbs survive to the present; all are dead by 10,000 years ago (with the possible exception of one gomphothere, about which claims are made for a late survival)
    In Asia, the last mammoths survive until 8-9,000 years ago on the mainland, but on one arctic island they survive till the rise of modern civilzation.
    In Africa, most big game survives into the Holocene, but on Madagascar, all giant lemurs, giant flightless birds, and hippo species are killed off between 1,000 AD and 1700 AD.
    In Australasia, all giant marsupials, giant land turtles, and some giant flightless birds become extinct 40,000 years ago (some 30,000 years before any other continent loses its megafauna), however, this only applies to the mainland: on offshore islands, such as New Caledonia, giant land turtles survive until a few thousand years ago.
    In New Zealand, the giant flightless birds and giant eagle (among other species) survive until about 1200-1300 AD.
    In the Galapogos Islands, where humans never lived, giant tortoises and giant lizards continue until the islands' discovery by Europeans.

    No one event can correlate to the loss of all animals over 200 pounds in Australia 40,000 years ago, the death of all but three herbivores larger than 750 pounds in the Americas 10,000 years ago, and the similar loss in Europe about the same time. Nor can it correlate with the retention of megafauna in Madagascar, NZ, Cuba, etc. until well into the Holocene. But if you correlate these extinction events with the coming of man, you begin to see a patter. Modern man hits Europe about 40,000 years ago (if not earlier), and the megafauna are gone within a few ten thousand years. He reaches the Americans 12-20,000 years ago, and the megafauna disappear within a few thousand years. He reaches the Caribbean about 5+ thousands years ago, and then the last ground sloths, whose Florida cousins 70 miles away had been extinct for 6k years, disappeared–same for NZ and Madagascar 800 y.a. We did it!

  5. What I don't understand is that, if the extinction of mammoths and saber tooth cats, among other fauna, was caused by overhunting by a handful of primitive humans with spears and stone axes, then why, after guns were invented hundreds of years ago, weren't elephants, lions, tigers and bears completely wiped out as well? They still exist, even though humans had multiplied a million fold and created weapons of mass destruction. I don't think this theory holds a drop of water.

  6. He laughs at Impact Hypothesis cause he stupid as fuck, and think its only one thing that is cause the extinctions, why not all, comet or asteroid hits, caused all of the problems, life strugles, and humans that survives catastrophe hunts what they could and whats left, to fucking survive, and plus climate change that occurs because of impact, all geology records and proxies shows that fucking impact happend, for fuck sake there is over 500.000 oval shaped craters all over North Carolina, all oriented in one direction, so fuck you mainstream academia you stupid ignorant egoistic fucks, grow fucking up, open your mind a little bit, do not be so shallow and limited like cans

  7. Here is a thought all these animals we will take the horse for example you keep saying this species of horse is extinct. Well maybe its not a separate species of horse but just a different ethnicity but still just a horse. I mean humans have different ethnicity but we don't say an Asian is a different species of human. Those are all horses just a different ethnicity just like humans have. And just because a species has a bigger version of itself in a different area does not make it a separate species either. Deer in the south are much smaller than deer in the North but they are still white tail deer. I'm bored with scientists acting the way they do trying to claim their own discovery of a new species of animal. No dude you just found a different looking moose but its still just a moose.

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  9. X-rays from the sun and Cosmic rays and and a weak magnetosphere sterilized everything that couldn’t burrow or swim… our turn is coming .

  10. I hate it when archaeologist use  BP for dating.  It's not a dating method that most of us use, nothing wrong with BCE.

  11. 47:00 my first thought looking at the "spear tip" stuck in the ribs, was how could they possibly generate enough force even on level ground to stick that in there?. I am aware of spear slings but still probably a mating thing

  12. 29:10 "It is a herd animal. If You find one skeleton You find a bunch more" That not only says that it was a herd animal, but they all died at the same time. What was that catastrophic event?

  13. The answer to what caused the extinction is right there in his slides. There were none of those animals anywhere near the Hudson Bay Area. That’s because there was a polar shift. The North Pole was once centered in that area. That’s what created an ice free corridor and eventually a bridge from Asia to Alaska. That’s why you see some of those animals reaching up into Alaska but not further Northeast. The climate shifts and zone changes killed off many animals. This was felt way into Siberia where mammoths in plush Savannah were suddenly plunged into the cold. That’s why we find so many preserved in pristine condition in the permafrost. They were almost flash frozen by the polar shift to its current location.

  14. I really like that he tries to stick to facts and not conjecture. But in 2018 we know one thing he's passionate about is wrong. There is now evidence of humans hunting ground sloths.

  15. THIS MAN IS FULL OF CA-CAH. HE'S CITING THE MOST INNOCUOUS OF RESONS TO AVOID TALKING

    ABOUT THE MOST LIKELY, AND PROVEN CAUSE OF EXTINCTIONS. SOLAR-DRIVEN ICE-AGES, WHICH

    TRIGGER COOLING BY CLOUD NUCLEATION, VOLCANIC OARTICULATES THAT BLOCK THE SUN,

    REDUCTION OF SOLAR WIND THAT PERMITS GREATER COSMIC RAY QUANTITIES TO CAUSE CLOUD-

    FORMATION, HIGH ALBEDO, HIGH REFLECTION OF SOLAR RADIATION, AND DOWNRIGHT SOLAR

    EMSSIONS WEAKENING, ALL WHICH ARE CYCLICAL. WASTE NOT YOUR TIME ON THIS, HE'S A FOOL

    IMPLYING THAT PLANTS MOUNT A DEFENSE AGAINST BEING EATEN. THE FOOL!!

  16. I enjoyed this presentation but I also have a bone to pick with it. To question the extinction of megafauna in South America due to a North American impact is to ignore the demise of the Dinosaurs, world wide, due to a Central American impact. This is the same thing as calling a time in the past that had co2 levels of 2,000 ppm a climate optimum and then calling our current levels of a paltry 450 ppm global warming. If the co2 levels were to drop to 175/150 ppm all life would end on earth. We don't have science, we have dogma. Dogma is a cancer. Also this guy is completely ignoring sites in Virginia that show human Solutean (European) habitation 14,500 years ago. Prior to Clovis. As I said…Dogma is a cancer.

  17. annoying audience laughed every couple minutes as if they were in a comic club… nothing funny at all.
    Great presentation.

  18. If the animals were super size, is it possible that the humans were super sized also? The Bible reports the people were giants.

    It’s a puzelment!

  19. There actually is evidence of humans consuming ground sloths: http://www.cbc.ca/news/technology/mega-sloth-likely-on-humans-ice-age-menu-1.1143512

    The fact that humans drove the late Pleistocene extinctions is, frankly, indisputable. There is no better explanation for the simultaneity of extinctions on three continents and several large islands, and even possibly Europe, Africa, and Asia, with the arrival of humans to these regions.

    Climate change theorists simply do not have much of an argument; these animals had survived worse shifts in climate, so why did this one kill them, and why so sporadically?

    The hypothesis is not necessarily that humans hunted them all, but that they impacted their environment enough to drive megafaunal extinctions, via a variety of mechanisms, possibly including overkill, burning land, clearing forests, introducing diseases, and even just competing with native fauna.

  20. He is in Washington and not one mention of the black mat or the scablands flood? It is in his backyard. 50 foot high, 5 mile wide current ripples on the ground, dry falls and so on is not worth one slide in the presentation? I am not expert but "no evidence of mass fires"? What is the black mat layer? Great info on the animals themselves, but lacking in the event that killed them. Are universities echo chambers? I don't get how evidence is just dismissed. I would rather hear why he thinks this is not a factor rather than just not addressing it.

  21. I'm confused – in about the 27th minute he's saying horses went extinct in North America until they were re-introduced by Europeans. If that's right then my mental image of early western explorers encountering native Indians on horseback can't be right can it? I'm perfectly sure my mental image is far from accurate, but surely the bit about them riding horses was right, wasn't it?!

  22. Um bone point he talked about has been reported to be bison bone. If correct I do think that creates a problem for his hypothesis. I am also aware of mass kill sites of Long horned bison. No question about it. Time Team America did a show about it. Osage orange and one kind of locust have nasty thorns. There is also a location in CA where the sides of a very large stone has been rubbed smooth at a height that limits the options to Imperial Mammoth.

  23. How does an extinct mammal never appear in North America again, unless re-introduced later on?..how can something that is extinct (doesn't exist anymore) get re-introduced at a later time??????? Serious question, and I want a serious answer!!!!

  24. Excellent presentation. Grayson provides the best arguments i have seen why hunter-gatherers could not have caused the magafauna extinction. Most of all, i love it when a researcher can simply say how we just don't know yet.

  25. Excellent presentation. Grayson provides the best arguments i have seen why hunter-gatherers could not have caused the magafauna extinction. Most of all, i love it when a researcher can simply say how we just don't know yet.

  26. The more interesting question is why these extinct megafauna genera survived the six interglacial periods of the last 2.5 million years but not this current one. OR were there similar megafaunal extinctions during those interglacials we don't know about?

    I live in the Sonoran desert and paleobotanists say the flora was much different >15,000 BP when most of the megafauna disappeared.

  27. The discovery of the St Paul's Island mammoth contributes to the theory that hunting contributed to the extinction of the megafauna. Native Americans didn't live there till till Russians took them.

  28. The hunting theory is so pathetically weak it defies logic. When Europeans came to No.America it was teeming with wildlife and native humans were everywhere. The animals at that time were much smaller than the extinct ones. By the hunting theory logic, all animals should have been extinct given the relatively dense human population (compared to 10,000 BC). Plus the size of the extinct predators is really terrifying and puny humans would have been prey. Also after a kill the predators will show up and guess who's likely to win?? The hunting theory is DOA on the start line.

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