The worst problem uniformitarian scientists encounter with the extinction of the Siberian woolly mammoths is that they disappeared not just in Siberia but everywhere at about the same time. Another major difficulty they face is that many other animals also went extinct at the same time, near the end of the Ice Age. On North America, 70 percent of mammals weighing over 100 pounds (40 kg) disappeared.1 This represents about 100 species of large animals that included mammoths, mastodons, saber-toothed cats, giant ground sloths, giant beavers, giant peccaries, dire wolves, short-faced bears, and many others. The American mastodon is a type of elephant that lived mainly in the eastern half of the United States during the Ice Age. It differs from the woolly mammoth in being shorter and more heavyset, and having less hair and less curvature of the tusks.2 About three-fourths of mammal species went extinct on Eurasia.3 Mass extinctions also occurred in the Southern Hemisphere. Australia lost 90 percent of its large animals including the giant kangaroos and wombats.4 Strangely, these mass extinctions occurred at a time when the climate was supposed to be warmer with more glaciated land becoming exposed upon melting. Their paradigm or major belief system leaves them with a climate that does not explain how the animals found enough food to thrive or how they survived the inhospitable Ice Age climate. (Possible explanations for disharmonious associations are presented in appendix 2.)
There are two main hypotheses in vogue today to account for these extinctions at the end of the Ice Age: (1) either they died because of the climate change, the overchill hypothesis, or (2) man killed most of the large animals in a great slaughter, the overkill hypothesis.5 The two sides in this conflict are at such odds that it is almost a war between them — a war of ideas.
A third hypothesis has recently entered the dispute, namely that people sparked the extinctions by introducing epidemic diseases: the overill hypothesis.6 The disease vectors could have been introduced to the wild animals by the organisms that normally accompany man, such as dogs, cats, rats, fleas, etc. However, there is little evidence to support this new hypothesis.7 Howorth8 examined the possibility of disease long ago and concluded that it was extremely unlikely. This was because disease could not affect that many animals over such a wide area. Furthermore, evidence for disease should be seen in the remains, but the animals appear to have been healthy when they died.
Extinction by climate change?
Many geologists favor massive extinctions from the climate changes that occurred at the end of the Ice Age. The timing is certainly suggestive. Unfortunately, there are several objections to climate change alone being the culprit. The most common and serious argument is that the animals survived all the many supposed previous glaciations and interglacials with few extinctions.9 Since there are now thought to be about 30 separate ice ages,10 why would there be such a mass extinction only after the last? Daniel Fisher11 summarizes this argument:
Climatic hypotheses for late Pleistocene extinction face the challenge of explaining why this [last] deglaciation event had consequences for the fauna that were so much more drastic than earlier [ice age] events.
Climate enthusiasts counter that the climate change from the Ice Age to the present climate was unique and much harsher than the previous interglacials.12 But, this is unlikely. Stuart13 points out that there should be little, if any, difference between the present interglacial and previous ones.
Another objection is that as the ice sheets were disappearing and the climate was warming, more land became available for grazing animals.14 Instead of the overchill hypothesis, it should be the underchill hypothesis.15 The animals also could have migrated to a more suitable habitat as the climate changed.16 So, the likelihood of climate change causing their demise is still questionable.
Then there is the high probability that if the mammoths died out by climate change, their condition would show evidence of starvation or other climate-induced trauma. Comments of most workers indicate that the mammoths were apparently healthy when they died. According to Jeffrey Saunders, the Columbian mammoth on the Great Plains of the United States shows no evidence of long-term stress at the end of the Ice Age.17
- Animals survived many previous ice ages and interglacials.
- The present interglacial was not harsher than previous interglacials.
- The climate warmed while ice sheets melted.
- More land was exposed as ice sheets melted.
- Skeletons and carcasses were apparently healthy when they died.
- Most deaths of animals were well south of the ice sheet boundary in the United States.
If climate change caused the extinctions, one would expect evidence of more deaths in the north, closer to the ice sheets, than the southern part of the United States. However, 60 percent of the deaths occurred in the south. This is considered a firm refutation of the climate idea by some.18
Table 5.1 summarizes the evidence against the climate change hypothesis. These are formidable objections.
Extinction by man?
The alternative hypothesis is that man is responsible for the Ice Age extinctions, since man seems to be the only added variable to the last ice age compared to the previous 29 ice ages that uniformitarian scientists believe occurred. The overkill hypothesis as it is called is rather old, going back to the time of Howorth in the late 1800s.19 But Paul Martin and colleagues20 have revived it. Because of the objections to the climate change hypothesis, and noting that the time of extinction coincided with the time of man entering the New World, Martin believes man rapidly exterminated the animals in a great slaughter. According to Stewart, the fact that most of the animals that became extinct were large and were not replaced by other animals suggests that man was the culprit.21 One of Martin’s overkill models is the “Blitzkrieg model,” named after the ferocious German advances early in World War II.
Of course, overkill advocates are quick to mention all the animals and birds that man has sent to oblivion during recorded history. They remind us that within 600 years of man’s arrival in New Zealand, about 1000 AD, many bird species, including the giant moa, were exterminated.22 Scientists, who favor the overkill hypothesis, point out that some mammoth remains in the New World have Clovis spear points associated with the skeleton. The Clovis people are supposed to be the first humans entering the New World from Alaska about 11,000 years ago. There are little less than two dozen associations between mammoths and Clovis spear points.23
However, there are problems with the overkill hypothesis. The question can legitimately be asked: how can man kill so many animals within a few hundred years, especially when some of these animals ranged all over the Northern Hemisphere and were quite adaptable to various habitats? People were likely sparse at the time. The hunters had only spears, not a very efficient method to destroy millions of animals. These people depended upon hunting for food. They likely would not wantonly have killed off massive amounts of animals, like the buffaloes killed by rifles on the Great Plains of North America in the 1800s. Hunting for sport and wasting the meat would be very unlikely. To hunters and gatherers, the tusks and meat would be very useful, yet most of the mammoth tusks remain untouched.24 Hunters would surely have absconded with the tusks, so that few skeletons of mammoths would possess tusks. Stone25 describes the problem with overkill this way: “Considering the sheer number of species that went extinct, that argument runs thin — even if Clovis men were hunting from morning until night.”
Advocates of overkill counter that the animals, in North America at least, were not afraid of man and had not developed defenses against them,26 since the animals preceded man to North America. So, goes the theory, the animals were essentially “tame,” and it was like killing cattle. However, many think that it would not take long for the animals to adapt to aggressive people.
In answer to the objection that many genera of birds also went extinct in North America,27 Steadman and Martin28 respond that most of them were large carrion feeders and depended on a supply of large mammals.
In reference to recent extinctions of island birds and animals, such as on New Zealand, overkill critics point out that these species cannot migrate off the island and are especially vulnerable to hunting pressure.29 Furthermore, most of the modern-day mass extinctions or mass killings occurred with rifles, which early hunters with spears, of course, did not possess.
As far as the mammoth/spear point associations in the New World, critics of overkill further point out that there are relatively few of these sites in all of North America.30 And even the mammoth/spear point associations do not mean that man hunted the mammoth, but the associations could just as well mean that man killed some sick or dying mammoths.31
Furthermore, there are few, if any, signs of associations between man and the remainder of the extinct animals.32 This is why Martin advocated his Blitzkrieg model, which happened so fast as not to leave much evidence. One problem with Martin’s ad hoc subsidiary hypotheses is that there are many moa kill sites in New Zealand from the historical extinctions.33 This is overkill with much evidence lying around.
Grayson34 rightly challenges Martin’s view and maintains that because of such subsidiary explanations, overkill is untestable. The migrating Clovis hunters are assumed to be rather backward people using simple weapons, like spears. Some of these animals are dangerous and when wounded would be ferocious. How many would dare to spear a woolly rhinoceros? Furthermore, the hide of the mammoth is quite tough and would be very hard for a spear to penetrate. Based on the dissection of an elephant which died in a zoo, Laub35 comments:
Our own experiences with the elephant carcass left us skeptical about the wisdom of seeking to bring down a mammoth or mastodon primarily with spear thrusts. A thick coat of fur during at least part of the year, added to the thick skin known to have been present in mammoths (preserved in frozen carcasses) and presumed in mastodons, would probably have diminished the force of a striking spear.
Stone36 corroborates in describing an experiment with simulated Clovis weaponry and a dead zoo elephant. The Clovis points mostly failed to penetrate the rubbery skin.
Another argument against the overkill hypothesis is that in Africa man and animals are said to have coexisted for a million years or so with very few extinctions. Digby,37 long ago, had a good answer to this objection: Africa teems with food year around, and man had no need to wipe out animals. However, Digby’s argument can be turned around to question the overkill hypothesis in North America, since game was likely plentiful at the time.
Another problem for the overkill hypothesis is that some of the animals that disappeared were unlikely to have figured in the human diet.38 Then, there is the objection that many animals that should have been hunted to extinction, such as the bison, elk, moose, and reindeer, have survived to this day.
Although overkill enthusiasts lift up the North American extinction record as support, the correspondence of the meager archaeological record and mass extinctions in northern Eurasia and Australia seems contradictory.39 The extinctions in Eurasia and Australia are believed to stretch out over a period of about 40,000 years. This record is contrary to both the overkill and climatic hypotheses.40
- The population of people was sparse while animals were widespread over the Northern Hemisphere.
- Hunters only had spears and knives.
- Mammoth hide and hair was difficult to penetrate with a spear.
- Hunters normally don’t wantonly kill animals they use for food.
- Most mammoth tusks were left with the skeletons.
- Overkill was unlikely with island extinctions by man because the animals could not flee far.
- There are relatively few mammoth-spear point associations.
- Spear points associated with mammoths could be the result of man killing weak or dying animals.
- There were few associations between man and other extinct animals.
- There were many moa kill sites on New Zealand, while there were few mammoth kill sites.
- Africans have not killed off many animals over thousands of years.
- Many of the extinct animals would not have been part of man’s diet.
- Many animals that should have been hunted to extinction survive today.
- Dating associations between man and extinctions are questionable.
A number of the extinct mammals were carnivores, like the saber-tooth tiger. Why would these carnivorous animals also go extinct? Overkill enthusiasts counter that it is because the herbivores died out. This argument does not hold water because some large herbivores, such as the bison, elk, deer, reindeer, etc, remain to this day.41
Some scientists question the presumed date of the North American extinctions as concurrent with man entering the New World about 11,000 years ago. Most of these dates are based on carbon-14 dating. Krishtalka42 points out how the “dating” is likely a selection process:
Their selective acceptance of only the “good” dates — those that fit the model (for example dates for human beings in North America no older than 12,000 yr B.p., and those for mammoths no younger than 10,000 yr B.p.) — may play fast and loose with the evidence that doesn’t fit.
Grayson reinforces this possible juggling of carbon-14 dates to arrive at preconceived conclusions:
The timing of Ice Age extinctions is really very poorly understood. … Radiocarbon chronologies are bad in North America and worse in Europe.43
Table 5.2 summarizes the evidence against the overkill hypothesis.
Can both be correct?
However, no one seems to have considered the possibility that, at least as they were defined through the late 1980s, both hypotheses might be wrong.
After testing the Blitzkrieg model, Beck46 found that both main models appear to be wrong. As a result of tests and the many arguments against either hypothesis alone, many scientists have settled on believing that a combination of climate change and overkill explains the extinctions. Gary Haynes47 examined the problems with both hypotheses, but leans mostly toward climate change with man killing off already dying animals. I believe his stance on this issue has merit.
Some consider the combination of both hypotheses to be a weak approach because the combination is almost untestable.48 But Burney49 cautions that the more complex solution should not be rejected just because it is complex.
The debate rages on
Back in 1926 when Digby wrote his book on the mammoths, the extinction of the woolly mammoths had already caused much consternation among scientists for one hundred years:
Many scientists, including the great palaeontologists of this and other countries, have wrinkled their brows for a century over the problem of flesh-and-blood mammoths.50
One would expect that after 75 more years the problem would have been solved, not only for woolly mammoths, but also for the other animals that went extinct. Summarizing the results of a conference on extinctions, Grayson51 writes in frustration:
We have accumulated facts on the nature of ancient floras and faunas, on past climates, on human prehistory, and on the chronology of it all. These are precisely the kinds of facts that scientists have assumed all along are needed to provide an adequate explanation of late Pleistocene extinctions.
Nonetheless, from an historical perspective one of the most interesting lessons to be learned from this volume is that we are apparently no closer to that adequate explanation, or at least to agreement as to what that adequate explanation is. … The accumulation of facts, it would seem, has been of surprisingly little help in resolving one of the major problems that confronts the student of mammalian history. There is a question that can hardly be avoided, one that is nearly as interesting as the causes of the extinctions themselves: why has the huge increase in our knowledge of the past failed to move the issue detectably closer to a resolution? Why has so much time made so little difference?”
In a more recent conference on mass extinctions, Alroy52 throws up his hands:
After many decades of debate, the North American end-Pleistocene megafaunal mass extinction remains a lightning rod of controversy. The extraordinarily divergent opinions expressed in this volume show that no resolution is in sight.
Despite the enormous expense and accumulation of data, scientists are stymied. The extinction wars continue. Could the problem be in their basic assumptions regarding the past?