Given that a lot of megafauna have become extinct in relatively recent times, at least in certain regions - particularly in Europe - I suspect cultural attitudes had something to do with it. AFAIK, large animals have not generally been hunted in India, except during the colonial period, while many large animals are hunted in China for folk medicines and other things. (Rhino horn, anyone?)
India is also much more isolated than southeast Asia. To get there, you have to cross a mountain range or a thousand miles or so of desert. I don’t know whether there were more hospitable migration routes in neolithic times, but I don’t think so.
If you buy into the climate change theory of extinction, you have to explain how these species had survived radical climate changes multiple times in the past. (During previous interglacial periods.)
What is the one notable way in which the most recent interglacial period is different? The arrival of modern humans.
Such as? I assume we’re talking large mammals, right?
Spoke- if you buy into the humnas lilled them all by hunting you have to explain:
whay many megafaunal animals survived just fine- Bison, Grizzley bear, Moose, Elk, and so fothr.
And why, since the introduction of modern firearms we have not managed to cause the extinction of any large, successful species of mammals. You’d think with a population 1000X more and a weapon 1000X more deadly, we’d have done a better job. Not that quite a few species aren’t just barely hanging on, and not that we didn’t come close a couple of time. But that is the “exception that proves the rule” as generall when hunting drives a species down to low levels, too few to hunt (for food) hunting pressure drops off. The Bison is an excellent example, along with the Grizzly. Although B.*Bison is smaller than B. antiquus *, they overlap in size, as do the short-faced bear and the Brown bear. We still have plenty of Megafauna around.
And, you’d think that in NA there’d be some, like “evidence” of such a mass kill. But there isn’t. "If indeed, Human, or as Martin argues- Clovis man hunting, caused the megafaunal extinctions, you’d think there’d be more evidence. As of that article above (2002), there were exactly and only 14 (fourteen) sites that solidly show such evidence, and that evidence is confined to just two genera- mastadon, and mammoth. “… there are no demonstrable kill sites for camel or horse or for any of the remaining genera…”. In other words, looking purely at the record, Clovis man can be shown to have killed just a few mastodon and mammoth in North America. Oddly "After all, in other parts of the world- Late Pliestocene Europe, for example- are littered with sites that document human predation on large mammals. Martin claims that the killing in North America happened over such a short period of time that “we should not expect to find empirical evidence of that process”." There’s a site in Europe that shows like a 1000 kills of Mammoth- that’s one single site. In America we have a handful.
All the evidence that humans caused the extinctions is based upon coincidence. (Well, except in NZ). There’s not even a Theory that humans did so.
new article: http://www.sciencemag.org/cgi/content/abstract/306/5693/70
*Assessing the Causes of Late Pleistocene Extinctions on the Continents
One of the great debates about extinction is whether humans or climatic change caused the demise of the Pleistocene megafauna. Evidence from paleontology, climatology, archaeology, and ecology now supports the idea that humans contributed to extinction on some continents, but human hunting was not solely responsible for the pattern of extinction everywhere. Instead, evidence suggests that the intersection of human impacts with pronounced climatic change drove the precise timing and geography of extinction in the Northern Hemisphere. The story from the Southern Hemisphere is still unfolding. New evidence from Australia supports the view that humans helped cause extinctions there, but the correlation with climate is weak or contested. Firmer chronologies, more realistic ecological models, and regional paleoecological insights still are needed to understand details of the worldwide extinction pattern and the population dynamics of the species involved. *
Seems to indicate that in the Northern Hemisphere pronounced climatic change was key.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WH8-47TX02J-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=3d134a011541bd289af964b98ce0908d
A requiem for North American overkill The argument that human hunters were responsible for the extinction of a wide variety of large Pleistocene mammals emerged in western Europe during the 1860s, alongside the recognition that people had coexisted with those mammals. Today, the overkill position is rejected for western Europe but lives on in Australia and North America. The survival of this hypothesis is due almost entirely to Paul Martin, the architect of the first detailed version of it. In North America, archaeologists and paleontologists whose work focuses on the late Pleistocene routinely reject Martin’s position for two prime reasons: there is virtually no evidence that supports it, and there is a remarkably broad set of evidence that strongly suggests that it is wrong. In response, Martin asserts that the overkill model predicts a lack of supporting evidence, thus turning the absence of empirical support into support for his beliefs. We suggest that this feature of the overkill position removes the hypothesis from the realm of science and places it squarely in the realm of faith. One may or may not believe in the overkill position, but one should not confuse it with a scientific hypothesis about the nature of the North American past.
*Megafaunal extinction in the late Quaternary and the global overkill hypothesis
The global blitzkrieg hypothesis explains differential rates of megafaunal extinction between the world’s landmasses in the late Quaternary based on a proposed leap in predation efficiency enjoyed by colonising societies. It is characterised by appealing simplicity. Selective over hunting, facilitated by naivet to human predation, produced rapid mass extinctions of large animals wherever subsistence societies colonised new landmasses. Taken at face value the circumstantial case for blitzkrieg is compelling and despite a paucity of direct evidence it has gained considerable support. Our review of the model suggests that it overlooks much contradictory data and rests on simplistic interpretations of complex biogeographicat and anthropological phenomena. These interpretations and assumptions do not account for major differences between the biotas, ecologies and human cultures of the landmasses involved. The assertion that responses of remote island species to human predation provide realistic models for those of continental taxa is poorly founded, exaggerating the likely predation efficiency of humans colonising continents. An absence of terrestrial predators over evolutionarily significant periods, together with restricted ranges and small populations, renders island faunas uniquely vulnerable to invaders. The argument, that climate cannot explain these phenomena because previous Glacial Maxima did not cause comparable extinctions, presupposes that their local effects were at least as severe as those of the Last Glacial Maximum. This has yet to be demonstrated and at most it would indirectly support a role for anthropogenic influence, not overkill per se. Overlooked or underplayed are the influences of translocated and other invading species. Similarly, differences in the origins, technologies and traditions of colonising human societies are rarely considered. These factors strongly impact on the predation efficiency, density and range of human populations, critically affecting the outcomes of predator-prey modeling. When a fuller constellation of influences and constraints is considered it is reasonable to posit that rapid mass extinction through selective human predation may largely describe megafaunal extinctions on remote islands, but the argument is not convincing for continents. This is especially so regarding Australia. Because even the largest Australian species were prey to endemic carnivores, their responses to human predation would not have been comparable to those of oceanic island species. No kill-sites or specialized big-game hunting/butchering tools are known and, on the basis of ethnographic and archaeological data, it is probable that predation efficiency, population density and range of the first Australians were insufficient to effect rapid mass extinction. Chronologies of human arrival and the disappearance of megafauna remain poor, but the most recent estimates for human-megafaunal coexistence in Australia range from 10,000 to 43,000 years. Although human predation may have been a contributing factor in megafaunal extinctions, rapid overkill is unlikely to describe the actual mechanism in most instances. The role of human predation and its significance relative to competing factors, human and otherwise, varied considerably between landmasses, as did the speeds with which extinctions occurred. Blitzkrieg and other mono-factorial models are heuristically valuable devices, but a growing body of evidence suggests that extinction can rarely, if ever, be attributed to a single cause. *
Not weighing in on the overall question of human-induced extinctions, but the quoted argument seems a little weak. Species that would have been extinct without deliberate concerted conservation efforts I think count as evidence FOR the ability of humans to wipe out animal populations, rather than ‘exceptions that prove the rule.’
Since the arrival of firearms in North America, passenger pigeons have been completely wiped out. East of the Mississippi, wolves, panthers, bison, and grizzlies are completely gone, and elk were gone (but have been reintroduced in some areas from western populations). Bison and wolves survive in the west in very small numbers and very limited areas only because of deliberate conservation efforts. I don’t think that’s doing too badly from a wipe-things-out perspective, given that it’s been only three-four hundred years.
West/central Europe didn’t have as many megafauna to start with, but did wipe out wolves since the introduction of firearms. I’m not sure how many species fall into the ‘sustained only by conservation efforts’ category there.
What do you mean “mass kill”? It’s not like they would have all been killed in one place or at one time. If they were killed by nomadic hunters, the remains would be scattered. And anyway, we’d be talking about just a few generations of remains that might show evidence of a human hunting among thousands (or even hundreds of thousands) of generations that had come before them and which had no exposure to humans. Needle. Haystack.
Pigeons are neither mammals nor Megafauna. And there is a stong debate as to whether hunting or habitat destruction is the primary cause. Likely both were needed.
As to bison, there’s now 350,000 or so. Hardly “very small”. Maybe 70,000 wolves, mostly in Canada.
*Shortcomings of the Hunting Hypothesis
The major objections to the theory are as follows:
In predator-prey models it is unlikely that predators could over-hunt their prey since predators need their prey as food to sustain life and reproduce.[20]. This criticism has been rejected by many ecologists because humans have the widest dietary choice of any predator and are perfectly capable of switching to alternative prey or even plant foods when any prey species becomes rare. Humans have indisputably hunted numerous species to extinction, which renders any argument that human predators can never hunt prey to extinction immediately invalid.
There is no archeological evidence that megafauna other than mammoths, mastodons, gomphotheres and bison were hunted. (Meltzer) Overkill proponents, however, say this is due to chance and the low probability of animals with low populations to be preserved. (Martin)
A small number of animals that were hunted, such as a single species of bison, did not go extinct. However the surviving bison species in North America was a recent Eurasian immigrant that arrived in the Americas at approximately the same time as humans and was thus well-adapted to human hunting pressure. In contrast at least three endemic American bison species did become extinct. Bison also are r type herbivores and reproduce rapidly compared to other species that did go extinct such as proboscideans and horses.
The dwarfing of animals is not explained by overkill. Numerous authors, however, have pointed out that dwarfing of animals is perfectly well explained by humans selectively harvesting the largest animals, and have provided proof that even within the 20th century numerous animal populations have reduced in average size due to human hunting.
Eurasian Pleistocene megafauna went extinct in roughly same time period despite having a much longer time to adapt to hunting pressure by humans. However, the extinction of the Eurasian megafauna can be viewed as a result of a different process than that of the American megafauna. The latter case occurred after the sudden appearance of modern human hunters on a land mass they had never previously inhabited, while the former case was the culmination of the gradual northward movement of human hunters over thousands of years as their technology for enduring extreme cold and bringing down big game improved. Thus, while the hunting hypothesis does not necessarily predict the rough simultaneity of the north Eurasian and American megafaunal extinctions, this simultaneity cannot be regarded as evidence against it.
The hypothesis that the Clovis culture represented the first humans to arrive in the New World has been disputed recently. (See Models of migration to the New World) *
And The survivors are as significant as the losses: bison, moose (recent immigrants through Beringia), elk, caribou, deer, pronghorn, muskox, bighorn sheep, and mountain goats. All save the pronghorns descended from Asian ancestors that had evolved with human predators is very disengous. Lets look at the bison. True, bison did emigrate from asia… but they did so 2 species back and 3 million years ago. Which 3 millions years ago, they hardly were adapted to human hunting. "During the Pleistocene Ice Age, steppe wisent (Bison priscus), migrated from Siberia into Alaska. This species then developed into the long-horned bison (Bison latifrons) which lived in North America for 3 million years. About 22,000 years ago, the long-horned bison gave way[clarify] to the Bison antiquus. B. antiquus were abundant from 18,000 years ago until about 10,000 years ago, when they became extinct, along with most of the Pleistocene megafauna. "
And although no doubt quite a few megafauna did go extinct, it now seems like the dating of all the extinctions to the arrival of “Clovis man” is doubtful: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WH8-4JJFY36-4&_user=10&_origUdi=B6WH8-47TX02J-2&_fmt=high&_coverDate=03%2F31%2F1989&_rdoc=1&_orig=article&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=a5f5a72215fb24316fb0e1e552b0ddf4 The chronology of North American late pleistocene extinctions
Abstract
For more than two decades, it has been assumed that all or virtually all North American terminal Pleistocene extinctions occurred between 12,000 and 10,000 years ago. However, analysis of the North American radiocarbon chronology shows that there are only 71 taxon dates pertaining to these genera that appear valid. These dates apply to nine genera, of which only seven have been dated to the terminal Wisconsin; 40 of these 71 taxon dates are for mammoth and Shasta ground sloth. The dates suggest that many of the extinctions may have occurred before 12,000 years ago, and show that most practitioners continue to extract dates of doubtful validity.
Finally, Bear, wolf and Bison are considered survivors, although this article does show the problem is deeper and more complex that I suggested:
Before humans emigrated from Africa some 60,000 years ago and populated the rest of the world within the following 50,000 years [6], all continents were inhabited by a variety of large animals, ranging from the herbivorous mammoth, giant deer or woolly rhinoceros to carnivores such as sabre-tooth cats and the giant short faced bear and birds like the giant Australian thunderbird Genyornis, to name just a few. However, 10,000 years ago, only about 50 of the original 150 genera of large mammals were left. The extent of the extinctions ranged from nine genera in Eurasia to as many as 50 in South America. Despite extensive research over decades, the reasons for these extinctions remain largely elusive…
However, the situation is more complex on other continents. In particular for the North-American continent there has been an extensive debate about the possible causes of megafauna extinctions [8] and [9]. Given that the key issue is the role of humans, the debate has sometimes been fierce. The views range from an exclusive human responsibility 10 P.S. Martin, Prehistoric overkill: the global model. In: P.S. Martin and R.G. Klein, Editors, Quaternary Extinctions: A Prehistoric Revolution, University of Arizona Press, Tucson (1984), pp. 354–403.[10] to a total absence of human influence on the extinction of these species [9]. Analyses of island faunas convincingly show that humans have driven species to extinction in the past [1], but it is unclear whether island analyses can be extrapolated to continents, where species usually occupy much larger habitats and come in greater numbers…
Impact on Surviving Species
While understanding the causes of species extinction seems to be complex enough, the picture is further complicated by recent studies indicating that surviving species may also have been affected by the Late Pleistocene extinctions, albeit in rather unpredictable ways. In 2002, Barnes et al. [2] found evidence that a local population of brown bears had become extinct in Alaska some 35,000 years ago and that the region was subsequently recolonised by genetically different brown bears about 20,000 years ago…
As shown for bisons, most of the genetic diversity of megafaunal animals may have been lost at the end of the Pleistocene, even in surviving species [4]. Moreover, most of this diversity seems to have accumulated during the 100,000 years between the last two glacial maxima 130,000 and 30,000 years ago, respectively. Both the genetic diversity and the ecological adaptations of populations may therefore be much more ephemeral than previously believed. While the results by Leonard et al. [5] do not immediately help in deciphering the causes of Late Pleistocene extinctions, they show that the ecological and population changes occurring at that time were rather complex and cannot simply be explained by the survival of some species and extinction of others.*
And, why were big mammals the only prey, why did the bigger the animal, the more likely to go extinct? http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6R-3SX5N1W-B&_user=10&_coverDate=12%2F05%2F1997&_alid=830936388&_rdoc=9&_fmt=high&_orig=mlkt&_cdi=5821&_sort=v&_st=17&_docanchor=&view=c&_ct=10476&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=496a26a99e9c0db3872daee05bf12f24 A predominant viewpoint on the dynamics of the Plio-Pleistocene exchange of mammalian taxa between the Americas invokes competitive displacement, i.e., the notion that North American stocks outcompeted their South American counterparts by virtue of greater resilience to extinction and higher rates of colonization and diversification. A recent statistical test (Lessa and Fariña, 1996) based on South American late Pleistocene mammalian genera failed to demonstrate any significant differences in extinction rates between South and North American stocks, but showed that body mass was the primary factor statistically associated with the probability of extinction. Here, we provide additional tests of differential extinction in relation to body mass, origin, and trophic niche, using data of North American late Pleistocene mammals, alone and combined with those of the previous study. Tests were carried out using genera as units and, when possible, also at the species level. The overall results corroborate the notion that body mass is the only factor to show a strong association with the probability of extinction, although there was an additional weak association with trophic niche.
Another significant reason for its extinction was deforestation. The birds traveled and reproduced in prodigious numbers, satiating predators before any substantial negative impact was made in the bird’s population. As their numbers decreased along with their habitat, the birds could no longer rely on high population density for protection. Without this mechanism, many ecologists believe, the species could not survive.
Disease is also given as as possible cause:The birds may have suffered from Newcastle disease, an infectious bird disease that was introduced to North America; though the disease was identified in 1926, it has been posited as one of the factors leading to the extinction of the passenger pigeon. http://www.petermaas.nl/extinct/speciesinfo/passengerpigeon.htm
*The extinction of the passenger pigeon was ultimately due to the effects of widespread clearance of its mast food (Bucher 1992), with the proximate causes being Newcastle disease, extensive hunting (Blockstein & Tordoff 1985) and the breakdown of social facilitation (Halliday 1980). It may be assumed that once the population has plummeted to certain levels, the species was doomed even though many individuals remained alive (Fuller 2000). The evolution of the passenger pigeon seems to have occurred in such a way that it could exist only in large flocks (Fuller 2000). *
If hunting is a pressure, bigger animals are probably more likely to stand and fight, rather than fleeing. Not necessarily a bad option for an elephant facing a pack of wild dogs, but against bows and throwing spears probably not a winning strategy, compared to bolting.
However, there are plenty of other non-human-related reasons why larger animals are more likely to go extinct. For instance, larger usually means longer generations means slower adaptation to changing environments. Larger also usually means fewer individuals, making the population more vulnerable to random events.
This section of your post, at least, seems to actually be a response to the criticisms of the “hunting hypothesis”. It lists the criticisms one-by-one and then explains how proponents of the hypothesis defend it against those criticisms.
And yet, you seem to be presenting it as evidence against the “Hunting Hypothesis”.
I’d meant to respond to this yesterday morning when I was on. However, it was already well past my bedtime, and I didn’t have the sites for the North American air-burst bookmarked. So I just subscribed and decided it could wait until I could get back in here.
I can’t believe nobody mentioned one of the most important protectors that megafauna throughout Africa have had over the ages - the tsetse fly. They (the megafauna) are all adapted to it; sleeping sickness (trypanosomiasis), carried by the tsetse, kills humans - slowly, in most cases, but inevitably. Thus far, there is no successful treatment for the infection, and nobody’s come up with a way to kill off the flies (which are live-bearers - i.e., the females gestate their young one by one). The only successful fly control measure thus far is the one the South Africans use.
As for North America. Haven’t any of you noticed the reports about the discovery of evidence of a comet air-bursting (PDF) thatended the Clovisculture? My first notice of it was a news blurb in Discover magazine last year. At the time, there was almost nothing available to the public online about it.
Yes, there are nay-sayers. I’ve seen this before. I can recall when nobody wanted to believe the Alvarezes about the dinosaur-killer. Eventually, the old fogies that don’t want to believe in the comet burst will die off, just as the ones who doubted the iridium layer at the K-T (Cretaceous-Tertiary) boundary. If you read the reports on this newly-discovered one, you’ll see they’re using the same kinds of evidence (excepting, of course, the iridium, which wouldn’t be there for an air-burst).
There certainly is evidence that hunting played A part. Most of what I quoted disputes “Overkill” (now completely discredited) but does allow for hunting as a significant factor.
However part of what I was disputing here on the wiki cite was that they used Bison- not as an example of megafauna that did survive despite the same hunting pressure, but as an example of a recent migrant. But the Bison is not a recent migrant by any means. The Bison sp that migrated to North America did so well before any significant hunting pressure. So, it’s a good example of a survivor.
If I’m not mistaken, the tsetse fly does not actually preclude human life from those portions of Africa; it does mean that most domesticated animals like cows and horses can’t survive there. So that would explain why megafauna in those parts of Africa weren’t replaced by livestock but doesn’t address the effect of human hunters.
