Results show that the correlation between climate change … and the loss of megafauna is weak
A new study unequivocally points to humans as the cause of the mass extinction of large animals all over the world during the course of the last 100,000 years.
Was it mankind or climate change that caused the extinction of a considerable number of large mammals about the time of the last Ice Age? Researchers at Aarhus University have carried out the first global analysis of the extinction of the large animals, and the conclusion is clear – humans are to blame.
“Our results strongly underline the fact that human expansion throughout the world has meant an enormous loss of large animals,” says Postdoctoral Fellow Søren Faurby, Aarhus University.
Was it due to climate change?
For almost 50 years, scientists have been discussing what led to the mass extinction of large animals (also known as megafauna) during and immediately after the last Ice Age.
One of two leading theories states that the large animals became extinct as a result of climate change. There were significant climate changes, especially towards the end of the last Ice Age – just as there had been during previous Ice Ages – and this meant that many species no longer had the potential to find suitable habitats and they died out as a result. However, because the last Ice Age was just one in a long series of Ice Ages, it is puzzling that a corresponding extinction of large animals did not take place during the earlier ones.
Theory of overkill
The other theory concerning the extinction of the animals is ‘overkill’. Modern man spread from Africa to all parts of the world during the course of a little more than the last 100,000 years. In simple terms, the overkill hypothesis states that modern man exterminated many of the large animal species on arrival in the new continents. This was either because their populations could not withstand human hunting, or for indirect reasons such as the loss of their prey, which were also hunted by humans.
First global mapping
In their study, the researchers produced the first global analysis and relatively fine-grained mapping of all the large mammals (with a body weight of at least 10 kg) that existed during the period 132,000–1,000 years ago – the period during which the extinction in question took place. They were thus able to study the geographical variation in the percentage of large species that became extinct on a much finer scale than previously achieved.
The researchers found that a total of 177 species of large mammals disappeared during this period – a massive loss. Africa ‘only’ lost 18 species and Europe 19, while Asia lost 38 species, Australia and the surrounding area 26, North America 43 and South America a total of 62 species of large mammals.
The extinction of the large animals took place in virtually all climate zones and affected cold-adapted species such as woolly mammoths, temperate species such as forest elephants and giant deer, and tropical species such as giant cape buffalo and some giant sloths. It was observed on virtually every continent, although a particularly large number of animals became extinct in North and South America, where species including sabre-toothed cats, mastodons, giant sloths and giant armadillos disappeared, and in Australia, which lost animals such as giant kangaroos, giant wombats and marsupial lions. There were also fairly large losses in Europe and Asia, including a number of elephants, rhinoceroses and giant deer.
Weak climate effect
The results show that the correlation between climate change – i.e. the variation in temperature and precipitation between glacials and interglacials – and the loss of megafauna is weak, and can only be seen in one sub-region, namely Eurasia (Europe and Asia). “The significant loss of megafauna all over the world can therefore not be explained by climate change, even though it has definitely played a role as a driving force in changing the distribution of some species of animals. Reindeer and polar foxes were found in Central Europe during the Ice Age, for example, but they withdrew northwards as the climate became warmer,” says Postdoctoral Fellow Christopher Sandom, Aarhus University.
Extinction linked to humans
On the other hand, the results show a very strong correlation between the extinction and the history of human expansion. “We consistently find very large rates of extinction in areas where there had been no contact between wildlife and primitive human races, and which were suddenly confronted by fully developed modern humans (Homo sapiens). In general, at least 30% of the large species of animals disappeared from all such areas,” says Professor Jens-Christian Svenning, Aarhus University.
The researchers’ geographical analysis thereby points very strongly at humans as the cause of the loss of most of the large animals.
The results also draw a straight line from the prehistoric extinction of large animals via the historical regional or global extermination due to hunting (American bison, European bison, quagga, Eurasian wild horse or tarpan, and many others) to the current critical situation for a considerable number of large animals as a result of poaching and hunting (e.g. the rhino poaching epidemic).
The results have just been published in the article Global late Quaternary megafauna extinctions linked to humans, not climate change in Proceedings of the Royal Society B.
The Dodo, Elephant bird, and Kiwi were some hunted by humans to extinction As the Maories had no land mammals to hunt, (Other than other Maories) but revelations also include the Kiwi nesting habits added to their extinction. That’s only in relative modern times though. Megafauna in Australia, some just evolved, like the red kangaroo, like the bison in America became smaller than the giant Bison. There is evidence Mammoths were hunted and wooly rhinos, so humans would have had some influence, but climate change was the biggest threat. Most of the extinct megafauna in Australia were browsers, not grazers and like all large animals especially marsupials that size, don’t breed often or have long gestation periods, like elephants, and the Aborigines preferred smaller game. They probably died out from drought that forced them to eat the available trees and shrubs as they collected around suitable waterholes. But it has been dismissed humans were the real threat to the megafauna. At worse it was the herds were desimated by human settlements. Elephants the warm climate Mammoth, are only hunted for their tusks, although some pigmies are thought to trap them for food. This theory has been dismissed anyway, why are they resurrecting it.? Remember, large animals fight to protect their young. And the technology wasn’t that advanced to bring down a mammoth with one shot. But there is evidence early humans on the American and European continent did trap them or drive them over cliffs.
Steve P says:
June 4, 2014 at 7:30 pm
The reality is that game animals like bison and deer were abundant in N. America at the time of the arrival of the Europeans. The native people seemed to have killed as many as they could, and they did it year after year, until their system collapsed, and the tribes disintegrated.
And Africa’s vast herds of wildebeest, antelopes, zebras, and giraffes are not herbivores?
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As addressed previously, African megafauna co-evolved with stone weapon-equipped humans for going on three million years, virtually the entire history of the elephant family on that continent. Likewise antelope & other large mammalian herbivores.
The megafauna of the Americas was much reduced after the arrival of humans. That some still existed, many of which were recent immigrants from Asia themselves, after humans had lived in the New World for 10,000 years or longer, doesn’t obviate the indisputable fact that the biggest Pleistocene animals & many of the smaller species all died out after the arrival of our species. To name but a few megaherbivore groups in North America wiped out by us, horses & their kin, camels, Camelops & llamas, mammoths, mastodons, gomphotheres, ground sloths, saiga antelopes, several tapir & peccary species, at least two bison species, stag-moose, shrub-ox & Harlan’s muskox & giant beavers, plus lots of big birds, fish & other vertebrates. By contrast, when Europeans arrived, the largest North American land animal was the American bison, much smaller than its Ice Age ancestors & relatives. The survivors of the Pleistocene/Holocene Blitzkrieg had learned how to live with their too successful human predators.
RACookPE1978 says:
June 4, 2014 at 8:34 pm
Correct. This behavior, killing the young & whenever possible adults of competitors & enemies, has been observed repeatedly among many carnivorous & even herbivorous species. Ditto intra-specific competitors & enemies.
The biggest reason for the decline in Elephant populations was due entirely the environmental movement. WUWT had a post a while ago about Alan Savory who was the instigator of the killing of over 40,000 Elephants in Africa to “save the environment”. Well surprise, surprise we was wrong.
Reblogged this on gottadobetterthanthis and commented:
While there is obviously room for doubt, this evidence is significant. Besides, we know we have extincted some species by hunting them. We still might extinct salmon and some of our other fish.
Hunting preserves are the way to ensure the wild ones stay with us. Hunters will not only pay for their hunts, they will pay because they will want to be able to do it again.
No Mammoths or hairy rhinos were in Africa. They were ice age megafauna. However, Tim Flannery wrote a piece that was recommended reading for one of my units in archaeology he wrote about the demise of African elephants (I think in Kenya?) And compared it with the demise of the megafauna.
Elephants walk from one water hole to another, eating on the way of course, but in a drought they stay put, and eat themselves out, and die from starvation. Made sense as one megafauna species skeletons were found around a dried out water hole in Australia. He then changed his mind and said humans were responsible. Well if they lasted for 10,000 years in Oz, they must have lived with the Aborigines for over 30,000 years at least! I think it is well thought out that until the 17th century, there were no horses for the North American Indians to ride and chase buffaloo/bison. And in Europe they didn’t ride horses until much later than after the megafauna died off, they hunted them instead.
BB, the horse actually originated in the Americas, and died out. Later models were reintroduced by the Spanish. The near-demise of the buffalo wasn’t at the hands of the Indians, it was European settlers. In fact, I recall reading somewhere that the settlers didn’t wipe out most buffalo for “fun” or for food, many were shot and left to rot- to deprive Indians of a food source.
The remains of a prehistoric human feast, or something else?
http://s8int.com/boneyard4.html
What is the one physical advantage, apart from intelligence, that humans have over all animals? Endurance running. Humans are the undisputed long distance running champions of the animal kingdom, with the possible exception of the horse. So one way early man hunted large animals was to literally run them to exhaustion.
http://en.wikipedia.org/wiki/Persistence_hunting
I forgot about the Moa in NZ. Thanks for reminding me. The Aborigines did not introduce the dingo exactly, it was from SE Asia most probably escaped or survived a ship wreck. It was domesticated dogs that probably killed off the Tasmanian Tiger, that had died out on the mainland many years before, and was a marsupial, probably competing with the dingo for prey. As few know that a bounty was put on Aborigines heads at one time by early Tasmanian colonists, and the whalers used to emasculate Aborigine men, and made their women sex slaves. Nice people we were once. Well we did a good job of killing quite a few Aborigines too, no wonder they tried to kill us back, but no chance against a bullet. The Tasmanian tiger was blamed for killing sheep.
The dingo didn’t cross Bass Straight as it was cut off from the mainland then from rising seas. Actually the dingo was never really domesticated by some tribes, as they competed for the same game, wallabies. And when it was it was only about 1000 years ago, and the dingo was probably domesticated or followed the camps to scavenge as its smaller canines developed or evolved indicating that they were not necessarily hunting for their own food.. However, they are not barkers, but great hunters and to breed dingos now, they are registered as a pure breed ( more pure bred than our present domesticated dogs) with Dogs NSW. But you can show them, but few do, and one has to have a special license to keep them in escape proof facilities with 12 ft fences. It’s mainly a conservation effort.
Bushbunny, it’s thought the dingo came to Australia via the Lapita people, who traded with Aborigines in Arnhem Land (and throughout Indonesian Archipeligo and SE Asia as well as Pacific). Since it arrived via the “hand of man” it can never be native.
NZ Willy
To make sense of your nonsense, how many species actually destroyed by man never to be seen again? Your tale is the favorite of tree-huggers. Man destroys the environment and all of man’s creations are evil. The poor sea cow was hunted to extinction but man produced over a billion cattle. They outnumber humans by weight. It must be bad because it’s man-made. We are giving man too much credit for extinction. We can’t even eradicate pests like cockroaches, termites, mosquitoes, rats with all our poisons. I suspect man will become extinct before cockroaches do.
Gigantism is an adaptation to cold weather. Deer in Texas are 100 pounds. Deer in Saskatchewan are 300 pounds. Megafauna, if used to a cold climate, would be at risk to warming. Trotting out Man as the cause of extinction is fun and useful to get grant money.
I believe that megafauna went extinct in Australia before the arrival of man..The synchroneity and rapidity of the Rancholabrean extinction also rules our human predation.
The paper may be useful in providing a bit of a clue to the relationships between climate and extinctions. Or rather, the lack thereof.
And I wouldn’t be surprised that humans were responsible for the demise of some slow breeding and probably relatively defenseless taxa. e.g. Giant sloths
But the notion that humans killed off large predators like saber toothed cats, North American Lions, short faced bears, dire wolves, etc strikes me as being quite unlikely. I think if Ogg the hunter-gatherer planned to live until the Summer solstice, he’d most likely give big carnivores wide birth. Likewise large fast breeding herbivores like horses and camels. Note that it’s not all that easy for modern humans using firearms and helicopters to control wild horse populations in the West. Yet a handful of hunters wiped them out?
Yes humans did wipe out the European Lion in historic times without firearms. But it took the Romans foraging for critters to stock the spectacles in the Coliseum to do it.
Arguably these megafauna became extinct because they resisted human efforts to domesticate them. Other mammals (horses, camels, sheep, pigs, goats, cattle, dogs, cats) adapted to man’s presence, allowing themselves to be domesticated, and they survived. Others (rats, mice) adapted to man-made habitats but avoid man at all times.
lokenbr says:
June 5, 2014 at 12:19 am
I nominate the dog, the hyena, and the bear, any of which can easily pursue and catch a man, and all of which have great endurance. A dog can lope all day. Fortunately, the horse is not a predator.
~
Early European accounts of the Inoca, or Illini tribes of the American Midwest, attesting not only to their skill as hunters, but also to the great abundance of game in the woodlands and prairies spanning their territory across the Mississippi, Illinois, and Ohio river valleys:
the modern weapon man had – the unique feature of humans, the one thing we have that ‘they’ do not – is fire. Having seen fire employed in the hunting process in Australia (light fire, watch prevailing wind carry it off over the horizon, eat first dead thing found) I can easily see how humans could have had an impact on megafauna
Steve P says:
June 4, 2014 at 4:43 pm
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No, I don’t have a count of Clovis points, but here’s something better: https://www.youtube.com/watch?v=TNP8ZjZ_cRU
Paleolithic man built their huts out of mammoth bones. See how silly it is to argue humans couldn’t have killed off the big beasts? It’s perfectly obvious they did. –AGF
And remember the great auk:
http://en.wikipedia.org/wiki/Great_auk
Who wiped it out? Modern man. –AGF
Gamecock says:
June 5, 2014 at 2:34 am
“Gigantism is an adaptation to cold weather. Deer in Texas are 100 pounds. Deer in Saskatchewan are 300 pounds. Megafauna, if used to a cold climate, would be at risk to warming. Trotting out Man as the cause of extinction is fun and useful to get grant money.”
Not just giantism and cold. There seems to be a smaller size that works best for many species. Coyotes can, and do, live about everywhere at approx. 35 lbs on the average. Wolves at 100 to 200 lbs, not so much. Island peoples are generally smaller except for those that eat ( or ate ) one and other. Resources available for food, ability to hide, agility, etc. all seem to come into play as to what size works best. This is not to mention that within species it seems that longevity is inversely related to size. Small dogs live much longer than large dogs. Go to a nursing home and look for old large people. Not many men of any kind in those places and even fewer old large men. More longevity=longer time to breed. When times get tough, for whatever reason, smaller seems to work better than larger, up to a point. The really small wild dogs of Africa do well because of their social system and their well known insanity in a fight. 20 to 30 of them have been known to take on a lion and while losing half their squad still successfuly kill and EAT the lion. On their own, though, I suspect they would not last long, too small.
Yes, but the video was short on evidence 1) that the hut builders had killed the mammoths whose bones they were using, or 2) that the hunting (if true), or hut-building played a major role in the eventual disappearance of these shaggy elephants.
I don’t doubt that men scavanged dead mammoths, or used their bones. What I doubt is that man was responsible for their extermination, especially when there is strong evidence it was nature what done it.
The vast bone-yards in Alaska speak of some enormous natural catastrophe, or perhaps series of them, which swept the great beasts from the land, and piled up their smashed remains in a semi-frozen mixture of bone, tusk, tundra, tree, and mud in the far north of the continent.
See:
Steve P says:
June 5, 2014 at 12:10 am
All of this may have occurred or culminated at around the same time frame as the mysterious YD.
In Africa the megafauna survived because they co-evolved with humans. That’s my theory, anyway.
Geology Joe says:
June 4, 2014 at 12:15 pm
“…Stop and think about the task of killing an elephant sized creature with a spear”.
The Arctic Inuit are expert whale hunters and have been prior to modern technology. They hunted whale from hand rowed boats using spears or rather harpoons. If they can do that then it is even easier to herd large land animals into bogs, ravines etc. and then spear them, with flint spears.
“I saw a TV show a few years ago and the stone age tools tested against mock elephants barely punctured the skin, let alone inflicted a mortal wound. Experimental test showed the “Exterminator” hypothesis to be highly unlikely.”
Interesting. I have also seen TV shows talking about stone tools and how lethal they can be. If the Inuit can immobilise whales with spears made from bone or stone that is enough evidence that any large animal can be brought down using cooperation, planning and stone tools.
Geology Joe says:
“Stop and think about the task of killing an elephant sized creature with a spear. I saw a TV show a few years ago and the stone age tools tested against mock elephants barely punctured the skin, let alone inflicted a mortal wound. Experimental test showed the “Exterminator” hypothesis to be highly unlikely.”
San hunters in Southern Africa habitually killed elephants with spears.
In Lehringen in Germany an 125,000 years old elephant skeleton was found – and underneath it a fire-hardened wooden spear. If they are unrelated that is quite a coincidence since wooden spears that old have only been found on three occasions. At one of the other two sites (Schöningen) the spears were associated with bison and horse remains.
There are in fact plenty of “butchering sites” with elephants and other megafauna throughout the world.
Steve P says:
June 5, 2014 at 9:27 am
Paleolithic man built their huts out of mammoth bones.
“…The vast bone-yards in Alaska speak of some enormous natural catastrophe”
Yes, perhaps and you can include all the Mammoth bones that North Sea Trawler men keep bringing up, but this study looked at extinctions on all continents and climate or natural catastrophe were not evident, such as Australia.
Rising sea level covered a vast plane in the North Sea that would have been home to many megafauna. One can imagine such large animals caught up in boggy land that wasn’t boggy before and following herd routes into such places much the same way people follow sat navs into rivers. However, and again this doesn’t apply to Australia.