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Thread: Large Mammal Extinction 10,000 years ago

  1. #1 Large Mammal Extinction 10,000 years ago 
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    Science has determined that the large mammals went extinct 10,000 years ago so my question is did the current biota of mammals we have today exist before the large ones became extinct?


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    Yes.

    It seems almost certain that the various waves of extinction affecting large mammals were caused by humans, from the 50,000 BP extinctions in Australia, to the 13,000 BP wave in North America, and the 800 BP extinctions in my country.

    The animals that continue to live in each of those countries existed before the extinctions. The reasons they still exist, is because each was able to resist the hunting efforts of primitive humans. Various mechanisms permitted this.

    For example, koalas in Australia survived because, with their diet of toxic eucalyptus leaves, their flesh tastes foul (not that I have tried), and they were not normally hunted. Bison in North America were too fast for primitive hunters who had no horses. and so on.


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    Quote Originally Posted by Barbi View Post
    Science has determined that the large mammals went extinct 10,000 years ago so my question is did the current biota of mammals we have today exist before the large ones became extinct?
    Got a link to anything supporting that assertion? Just curious...
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    Quote Originally Posted by skeptic View Post
    Yes.

    It seems almost certain that the various waves of extinction affecting large mammals were caused by humans, from the 50,000 BP extinctions in Australia, to the 13,000 BP wave in North America, and the 800 BP extinctions in my country.

    The animals that continue to live in each of those countries existed before the extinctions. The reasons they still exist, is because each was able to resist the hunting efforts of primitive humans. Various mechanisms permitted this.

    For example, koalas in Australia survived because, with their diet of toxic eucalyptus leaves, their flesh tastes foul (not that I have tried), and they were not normally hunted. Bison in North America were too fast for primitive hunters who had no horses. and so on.
    Every film that shows the large megafauna of mammals during that time frame never include the modern versions of mammals in their films. Here in North America, I have a hard time believing that early humans had any interest in eating a prehistoric armadillo (the size of a volkswagon bug) in their diet. Cheetahs were once here in N. America too but now only exist in Africa. It doesn't make sense to visualize a giant beaver living in the same area with a modern size deer.
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    Barbi

    Evolutionary biologists estimate the average 'life' of a species is a million years, before it either dies off or evolves into something else. You can take it as guaranteed that every native species currently in North America was there 10,000 years ago.

    As for eating armadillos - how do you know they were not delicious? People will eat anything if they are hungry. Dormice were a delicacy in medieval England. Rats are eaten in Indonesia. Africans eat elephant given a chance.

    As for cheetahs - humans have a habit of killing off predators if they can. Probably to remove a threat to their kids. And while an adult cheetah can run, its cubs are vulnerable to human attack.

    And why should a giant beaver not be in the same region as a deer?
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    Quote Originally Posted by skeptic View Post
    Barbi

    Evolutionary biologists estimate the average 'life' of a species is a million years, before it either dies off or evolves into something else. You can take it as guaranteed that every native species currently in North America was there 10,000 years ago.

    As for eating armadillos - how do you know they were not delicious? People will eat anything if they are hungry. Dormice were a delicacy in medieval England. Rats are eaten in Indonesia. Africans eat elephant given a chance.

    As for cheetahs - humans have a habit of killing off predators if they can. Probably to remove a threat to their kids. And while an adult cheetah can run, its cubs are vulnerable to human attack.

    And why should a giant beaver not be in the same region as a deer?
    How would an evolutionary biologists know that the average "life" of a species is a million years? They have no idea which species is the direct descendent of any of those fossils in the records. The fossil record is a snapshot of what they looked like at that time but it does not mean they went extinct, their descendents have changed over time so they no longer resemble their ancestors. You wouldn't say you were a new species if your direct ancestors looked totally different then compared to what you look like today.

    Every child born has genetics from both parents plus new ones created from the combination (mutations) and I would imagine after many generations that all of those new mutated genes eventually changes you in appearance and traits depending on the current environment you are living in that makes one adaptable. Those large mammals have a strong resemblance to our modern mammals so I would think that their descendents had already gone through the changes that made them smaller while still leaving a few individuals that were their direct ancestors.

    Once the environment stabilized with the new modern biodiversity of mammals, the larger ones died out leaving their direct descendents to carry on the production line. This of course is my opinion, since I don't completely believe all of the details of how this story is presented in education. All of the films about this time frame never show our modern mammal diversity living in the same era with the larger giant mammals. I can also understand why this is not done, simply because most people wouldn't believe it.
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    Just as a f'rinstance, take bison.
    BISON FOSSILS

    I quote :

    "Dispersing from Asia in numbers during the Middle Pleistocene Era, 300,000 years ago, the bison spread in vast numbers across North America. Despite the extinction at the end of the Pleistocene of native species of horse, llama and elephant, bison survived. "

    Extinctions en masse over the last 50,000 years have always 'coincided' with immigration of the first humans. Like the Australia aborigines who arrived 50 to 60,000 years ago. Their arrival was followed by the biggest mass extinction Australia has ever seen, with over 100 species of megafauna disappearing. In my country, the Maori arrived about 1200 AD. Within 150 years, 11 species of moa bird, and another 21 species of other bird species were extinct.
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    No one can prove that we are responsible for the mass extinction of megafauna. We may have played a large role but we have no way of knowing for sure at this point in time.
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    Coincidence only goes so far. We have too damn many examples for reasonable doubt.
    For example : the Polynesians colonised Pacific Islands between 12,000 BP and 1,000BP. The sub-fossil record shows that 2,000 native birds went extinct. In every case, soon after people reached their home island. Here in NZ, 36 species went extinct within 150 years of the arrival of the Maori people. In Australia, people arrived 50 to 60,000 years ago, and over 100 species of mega-fauna went extinct soon after. North America was the same picture - just different date.

    In law, guilt is 'proven' if beyond reasonable doubt. There is no reasonable doubt about the fact that, wherever humans moved, mass extinctions followed.

    In fact, there have, in many places, been two 'waves' of extinctions. The first when primitive humans arrived, and the second when modern humans arrived with rifles and rats.

    I am aware that there are a number of apologists for indigenous peoples who refuse to believe that the 'noble savage' could have been so destructive, and try to claim the extinctions are due to climate change, with warming 11,000 years ago. What those academic idiots fail to explain is how the species involved lived through 9 climate change events previously (interglacials) without dying out and then abruptly went extinct when humans appeared. Doh!
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    Yes, but we are blamed for killing off everything from Cave Bears to Wooly Mammoths. There is no academic consensus that this occured, although we certainly did hunt mammoths.

    http://www.nytimes.com/2009/12/22/sc...ndra.html?_r=1
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    gottspieler

    With the greatest respect to you personally, I have to say that the sad logic in your reference is most unconvincing. Humans arrived, and soon after a lot of animal species went extinct. However, the species that is perhaps most difficult to kill (the giant mammoth) did not go extinct for a few thousands of years, so the cause of extinction cannot have been humans?

    What rot!
    A more resistant species will take longer to wipe out. In the case of the mammoth, it is very, very cold resistant, and some populations probably lived in frigid areas relatively inaccessible to primitive man. So they took longer to kill. So what?

    Remember also that the human tribes involved were very primitive, with stone tipped spears for hunting tools. It is doubtful that they could have killed an adult mammoth with those weapons. Their predation would have been on mammoth young, and those young were probably well protected, making a kill less common. Thus, the species lasted longer than many other, more vulnerable species.
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    Quote Originally Posted by skeptic View Post
    Just as a f'rinstance, take bison.
    BISON FOSSILS

    I quote :

    "Dispersing from Asia in numbers during the Middle Pleistocene Era, 300,000 years ago, the bison spread in vast numbers across North America. Despite the extinction at the end of the Pleistocene of native species of horse, llama and elephant, bison survived. "

    Extinctions en masse over the last 50,000 years have always 'coincided' with immigration of the first humans. Like the Australia aborigines who arrived 50 to 60,000 years ago. Their arrival was followed by the biggest mass extinction Australia has ever seen, with over 100 species of megafauna disappearing. In my country, the Maori arrived about 1200 AD. Within 150 years, 11 species of moa bird, and another 21 species of other bird species were extinct.

    Then why do we still have so many mammals in Africa since many Humans never left Africa?
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    Barbi

    As I pointed out earlier, the mammals that remain are those that are 'adapted' in some way to resist human predation. Humans evolved in Africa. As a result, African animals have had the opportunity to evolve alongside humans, and develop that adaptation. Any that could not, disappeared a long time ago.

    You might be interested to know that, a million years ago, there were several species of small elephant in Africa. Are they extinct because they could not adapt sufficiently to resist human predation?
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    Quote Originally Posted by skeptic View Post
    Barbi

    As I pointed out earlier, the mammals that remain are those that are 'adapted' in some way to resist human predation. Humans evolved in Africa. As a result, African animals have had the opportunity to evolve alongside humans, and develop that adaptation. Any that could not, disappeared a long time ago.

    You might be interested to know that, a million years ago, there were several species of small elephant in Africa. Are they extinct because they could not adapt sufficiently to resist human predation?
    skeptic,

    Are you under the impression that humans had populated to such a point and had so many advantages that this is what caused those extinctions at that time. Life was difficult even with learning to use tools and fire for humans so I do not believe there were large numbers of us to create so much damage to the rest of biodiversity. We were also victims of predation from the smallest of critters to the largest of ones that we crossed paths with.

    Species have changed in appearance since the beginning of life by the new generations of offspring they produce over the eons. I do agree that we did have a impact when we began migrating to other ecosystems in that we became an "invasive species" to those critters living in that environment. It is most likely a combination of many factors that contributing to the end era of time for the large mammals.
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    Quote Originally Posted by skeptic View Post
    gottspieler

    With the greatest respect to you personally, I have to say that the sad logic in your reference is most unconvincing. Humans arrived, and soon after a lot of animal species went extinct. However, the species that is perhaps most difficult to kill (the giant mammoth) did not go extinct for a few thousands of years, so the cause of extinction cannot have been humans?

    What rot!
    A more resistant species will take longer to wipe out. In the case of the mammoth, it is very, very cold resistant, and some populations probably lived in frigid areas relatively inaccessible to primitive man. So they took longer to kill. So what?

    Remember also that the human tribes involved were very primitive, with stone tipped spears for hunting tools. It is doubtful that they could have killed an adult mammoth with those weapons. Their predation would have been on mammoth young, and those young were probably well protected, making a kill less common. Thus, the species lasted longer than many other, more vulnerable species.
    Yes, the logic in the article may be a bit off. My point is that we might not be the only reason for all of the megafauna dying out. I'll look for better sources.
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    Here is an explanation of how climate may have affected mammoths: http://www.anthropology.hawaii.edu/F...cation%204.pdf
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    Whether the climate change was anthropomorphic or not is not clear.
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    Climatic hypotheses


    Environmental insularity:

    Applied only to the extinction of the American mastodon; extinction occurs because boreal forest
    retreats northwards after glaciation, resulting in expansion of deciduous forest, which is less
    hospitable to the species

    Climate Change:

    Climatic changes, in the form of a slow transition from mosaic vegetation to a more zonal pattern, led
    to less hospitable environments for megaherbivores


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    gottspieler

    Your University of Hawaii reference pretty much backs up what I said. Climate change is not (except in a small way, perhaps) a cause of major extinctions.

    The place where climate change and extinctions coincide is North America, and that is due to the fact that humans crossed from Asia during more clement times, and were kept out during the colder glacial period. The actual extinctions were human driven.

    On your mastodon example, you have to explain why previous warm inter-glacial periods did not make it extinct. The previous one, for example, 125,000 years ago, came with a temperature rise that reached 1 to 3 C more than we have today. Why did the mastodon not go extinct then?

    After all, it evolved some millions of years ago, and survived 9 warm inter-glacial periods, and went extinct just after humans arrived. Still think it was climate?
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    On your mastodon example, you have to explain why previous warm inter-glacial periods did not make it extinct. The previous one, for example, 125,000 years ago, came with a temperature rise that reached 1 to 3 C more than we have today. Why did the mastodon not go extinct then?
    I think it was a combination of climate change and human hunting.
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    There remains, of course, another question.
    Why did some species die and others live? I have said it is because some species were more adapted to resist human predation. But that begs the question of "what adaptations"?.

    It is an interesting area for speculation. I suspect that fear, or the lack of it, was a major factor. We know the dodo went extinct very rapidly because it did not fear humans, and would walk right up to those who were looking for a dodo dinner. Is it possible that some of the giant species succumbed to human predators because they were not afraid of them?
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    Quote Originally Posted by skeptic View Post
    There remains, of course, another question.
    Why did some species die and others live? I have said it is because some species were more adapted to resist human predation. But that begs the question of "what adaptations"?.

    It is an interesting area for speculation. I suspect that fear, or the lack of it, was a major factor. We know the dodo went extinct very rapidly because it did not fear humans, and would walk right up to those who were looking for a dodo dinner. Is it possible that some of the giant species succumbed to human predators because they were not afraid of them?
    That or endurance hunting similar to that used by hunter/gatherers today was enough.
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    It is an interesting area for speculation. I suspect that fear, or the lack of it, was a major factor. We know the dodo went extinct very rapidly because it did not fear humans, and would walk right up to those who were looking for a dodo dinner. Is it possible that some of the giant species succumbed to human predators because they were not afraid of them?
    Social animals who have predators - all of the mammals and birds on the NA continent - are not fearless in the face of harm coming to them.

    The NA animals that survived the arrival of humans (at least, the arrival of these super-competent hunting variety) had no more experience of human hunting than the mammoths did.

    And quite a few animals disappeared that are very improbable hunting targets - giant vultures, condors, teratorns; cheetahs and lions and camels and horses, the shortfaced bear but not the black bear or the grizzly bear, the dire wolf but not the puma or timber wolf.

    There is a little evidence for a large meteor strike, and there is some evidence that humans made large scale alterations in an already limiting and stressed environment, which would explain the disproportionate number of very large animals that went under when people showed up.
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    Re 'improbable hunting targets.'

    Wiping out birds of prey is not that unlikely, if those birds did not fear humans. Primitive peoples have always loved eagle feathers, and will kill large birds for feathers for adornment, and as status symbols. Humans also have one advantage over most predators, with respect to raptors. We can climb to a bird's nest.

    Cheetahs and lions would be killed wherever possible to protect human communities. Camels and horses both provide excellent eating meat. Camel meat and horse meat are still popular foods in many parts of the world today.
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    Quote Originally Posted by skeptic View Post
    Iceaura

    Re 'improbable hunting targets.'

    Wiping out birds of prey is not that unlikely, if those birds did not fear humans. Primitive peoples have always loved eagle feathers, and will kill large birds for feathers for adornment, and as status symbols. Humans also have one advantage over most predators, with respect to raptors. We can climb to a bird's nest.

    Cheetahs and lions would be killed wherever possible to protect human communities. Camels and horses both provide excellent eating meat. Camel meat and horse meat are still popular foods in many parts of the world today.
    The bison lived in that time frame too so why would humans single out the larger mammals and camel and horse meat but leave bison alone for centuries until much later in time when we did wipe them out?
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    Barbi

    Bison would be left alone for the simple reason that a primitive hunter on foot with a stone tipped spear could not kill them. Occasionally, a baby bison perhaps, but even that would be difficult and dangerous. Bison are too big and too fast to hunt in the way those people could hunt.

    I could easily imagine a lot of the larger animals of the time would not fear human hunters, permitting them to come quite close. Or perhaps stalking techniques might work. Or as someone said, endurance hunting.

    The animals that survived are those that are too difficult to hunt. Wolves would be too fast. Mountain lions too secretive. Deer too good at running away. And so on. The species that were vulnerable were hunted to extinction.
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    I think you'll find that pretty well most of the megafauna extinctions of the last 20,000ish years were due to humans. Not only can we climb trees to get eggs from nests, which is a pretty good way to knock out whole species of birds, we don't need very sophisticated tools or skills to dig large pit traps, spiked or otherwise, to capture and kill large animals. And you only need time, not strength or agility or other physical skills, to gather and weave suitable materials to make strong enough ropes for nets and other kinds of traps.

    Remember, the most important thing about hunting is that you don't have to succeed every time. But if you succeed often enough with a large animal that has a slow breeding cycle, you'll certainly be able to make a species locally extinct. If your confreres on the other side of the mountains or desert or lake do the same in their area, there'll be none left in not very many human generations.

    The surviving individuals and species will be smaller, faster and more alert than the ones which turned out to be susceptible to methods relying on human skills with their hands and other exercises of ingenuity.
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    Quote Originally Posted by skeptic View Post
    Barbi

    Bison would be left alone for the simple reason that a primitive hunter on foot with a stone tipped spear could not kill them. Occasionally, a baby bison perhaps, but even that would be difficult and dangerous. Bison are too big and too fast to hunt in the way those people could hunt.

    I could easily imagine a lot of the larger animals of the time would not fear human hunters, permitting them to come quite close. Or perhaps stalking techniques might work. Or as someone said, endurance hunting.

    The animals that survived are those that are too difficult to hunt. Wolves would be too fast. Mountain lions too secretive. Deer too good at running away. And so on. The species that were vulnerable were hunted to extinction.
    Are you saying that a bison was too difficult for us to kill but the american cheetah and saber tooth tiger was easy to kill. Come on, even to you, it doesn't add up.
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    I think you will find that A chuck of the predators were driven quite possibly driven extinct by the loss of the prey animals more then direct predation by humans.
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    The clovis people did not arrive in N. America until 13,000 years ago and their numbers were most likely small, not enough to kill all those animals. The clovis people only lasted for 600 years until they were gone.
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    Quote Originally Posted by Barbi View Post

    Are you saying that a bison was too difficult for us to kill but the american cheetah and saber tooth tiger was easy to kill. Come on, even to you, it doesn't add up.
    Big cats often leave their cubs while they go hunting. Human hunters can track and kill the cubs. Not only can, they will.
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    Quote Originally Posted by Barbi View Post
    The clovis people did not arrive in N. America until 13,000 years ago and their numbers were most likely small, not enough to kill all those animals. The clovis people only lasted for 600 years until they were gone.
    When anthropologists talk of 'the Clovis people', they are not talking of a genetically distinct people. They are talking of a culture. It is almost certain that the peoples that followed the Clovis people were just the Clovis people who had evolved a different culture and way of life. As we all do over that kind of time period.
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    The animals that survived are those that are too difficult to hunt. Wolves would be too fast. Mountain lions too secretive. Deer too good at running away. And so on. The species that were vulnerable were hunted to extinction.
    Unless one simply assumes that the animals that went extinct were easier to hunt than any of the surviving animals they resembled, I see no reason to invoke ease of hunting as a factor.

    That shortfaced bears and condors and teratorns and lions and dire wolves and mammoths were easier to kill than grizzly bears, black bears, vultures and eagles, grey wolves, elk, pumas, and cranes, I find in need of serious argument with evidence. On first impression, the claim seems bizarre.

    Quote Originally Posted by adelady
    I think you'll find that pretty well most of the megafauna extinctions of the last 20,000ish years were due to humans.
    Humans normally have more serious impacts by their alteration of the environment - especially, fire - than by hunting.

    Note the large category of animals not much affected: aquatic and amphibious. They are easily hunted, but not easily deprived of habitat.
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    Quote Originally Posted by skeptic View Post
    Quote Originally Posted by Barbi View Post

    Are you saying that a bison was too difficult for us to kill but the american cheetah and saber tooth tiger was easy to kill. Come on, even to you, it doesn't add up.
    Big cats often leave their cubs while they go hunting. Human hunters can track and kill the cubs. Not only can, they will.
    Sorry, but I don't buy this explanation. It wasn't just in N. America that the large mammals could not be found but also the rest of the world. Fossil dating is not a precise as you might think, it can be off by a million years or more in dating. Carbon dating is not effective in Australia for some reason so they can really be sure of when those animals dissapeared. Recenty in Florida they found a saber tooth type creature that indicated that the large fangs the big cat had were much smaller in size and they believe it is another cousin species.

    In my opinion, this creature was the transitional from the large saber tooth tiger to the modern mountain lion we have today. Science already knows that the descendents will modify their appearance over time and this is obviously what has taken place with the strong resemblace of those large animals to their modern descendents we see today. I am not ruling out humans as the reaction to justify why those creatures became smaller over time.
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    Nature appears to have a strong investment in the reproductive process of life so while it is often stated that 99% of species is extinct, I think this is not accurate, the only thing that is extinct is their appearance in those time frames and of course those individuals since all life has a lifespan of existence. Appearances change over time through the reproduction process based on the changes that occur in their environment. I am not saying that none of them actually went extinct because I am sure some of them did but with the strong resemblances of the previous era of critters to todays creatures, it is most likely descent with modification.

    Humans are responsible in many ways since we have a direct impact on the environment in a fast rapid time frame. The reason we are responsible is because we aware of what we are doing to the environment and the impact it has on the other biodiversity of life. Did all of the other creatures have an impact on their environment, of course they did, are they aware of their actions? Probably not, what difference did it make, none.
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    Quote Originally Posted by Barbi View Post
    Quote Originally Posted by skeptic View Post
    Quote Originally Posted by Barbi View Post

    Are you saying that a bison was too difficult for us to kill but the american cheetah and saber tooth tiger was easy to kill. Come on, even to you, it doesn't add up.
    Big cats often leave their cubs while they go hunting. Human hunters can track and kill the cubs. Not only can, they will.
    Sorry, but I don't buy this explanation. It wasn't just in N. America that the large mammals could not be found but also the rest of the world. Fossil dating is not a precise as you might think, it can be off by a million years or more in dating. Carbon dating is not effective in Australia for some reason so they can really be sure of when those animals dissapeared. Recenty in Florida they found a saber tooth type creature that indicated that the large fangs the big cat had were much smaller in size and they believe it is another cousin species.

    In my opinion, this creature was the transitional from the large saber tooth tiger to the modern mountain lion we have today. Science already knows that the descendents will modify their appearance over time and this is obviously what has taken place with the strong resemblace of those large animals to their modern descendents we see today. I am not ruling out humans as the reaction to justify why those creatures became smaller over time.
    You do understand that the error range on radiometric dating is in the .01-2% range right? And that the nearer to modern times the fossil is from the more accurate the dating is?

    Do you have a quote/reference for widespread C14 dating problems in Australia?

    Reference for the smaller sabertooth cat in Florida?

    The problem is the genetics of the Machariodontinae subfamily members, such as the North American Sabertooth cats, is very distinct from that of the modern Felidae subfamily members including the puma and jaguarundi. So no they are not "transitional forms" that becam the modern NA cats.
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    All the animals that went extinct ~13000 during that period survived the even MORE abrupt climate change ~130,000 years ago. This, combined with a similar record of animal extinctions just about every other place humans colonized make a pretty strong case that humans were responsible--whether be by hunting, carrying diseases or added environmental stress or some combination of effects.
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    Quote Originally Posted by iceaura View Post
    Humans normally have more serious impacts by their alteration of the environment - especially, fire - than by hunting.
    Iceaura

    We have discussed this before. The animals that go extinct are not those vulnerable to fire. ie tree dwellers. They are the large meat animals or the ones that might prey on human children. eg. the koala is totally, utterly, completely vulnerable to fire. Yet it survived. Why? Because its flesh is foul, foul, foul due to its diet of eucalyptus leaves, meaning it was not hunted.

    Barbi

    Evolution does not happen in 13,000 years. So the megafauna of North American that disappeared did not simply change into other forms. Also, carbon dating works every bit as well in Australia as anywhere else.
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    Quote Originally Posted by skeptic
    We have discussed this before. The animals that go extinct are not those vulnerable to fire. ie tree dwellers.
    We have, and you continue to assert that "tree dwellers" are more vulnerable to human set fire than "ground dwellers", which is false; and that humans hunted animals like cheetahs (all three kinds) and lions and dire wolves to extinction while overlooking grizzly bears and black bears and bobcats and pumas and timber wolves, that they hunted birds like teratorns and condors to extinction while giving cranes and turkey vultures a pass, which makes no sense; that specific avoidance of humans is a genetic inheritance of co-evolved large mammals that passes down for thousands of generations in the absence of experience, and that intelligent herd mammals already predated upon by bears and the like would allow humans to walk up to members of their herds repeatedly and kill them, painfully, one at a time for generations, and never learn, which is ridiculous.

    Just one example:
    eg. the koala is totally, utterly, completely vulnerable to fire. Yet it survived. Why? Because its flesh is foul, foul, foul due to its diet of eucalyptus leaves, meaning it was not hunted.
    In America we have ecologically similar animals, porcupines. They were hunted both for food (they taste just fine, and can be found in the winter when food is scarce) and for quills etc. They are easy to kill and generally unafraid of human-type predators. They reproduce slowly, for their size. They had no genetic heritage of co-evolution with humans. Yet they remain - not hunted to extinction. We also have as survivors raccoons, and possums, again similar in some crucial ways (tree climbers, similar size) to koalas but avidly hunted by humans.

    We see in general relatively few extinctions of medium sized tree dwelling animals, in the human associated extinction waves, whether hunted or not. Habitat needs, more than suitability as food or ease of kill, seems to be a decisive factor.

    Quote Originally Posted by lynx
    This, combined with a similar record of animal extinctions just about every other place humans colonized make a pretty strong case that humans were responsible--whether be by hunting, carrying diseases or added environmental stress or some combination of effects.
    So. But humans being key factors in some way(s) is not the same as saying humans hunted all these animals from flourishing and stable populations to extinction.
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    Quote Originally Posted by iceaura View Post
    you continue to assert that "tree dwellers" are more vulnerable to human set fire than "ground dwellers", which is false; and that humans hunted animals like cheetahs (all three kinds) and lions and dire wolves to extinction while overlooking grizzly bears and black bears and bobcats and pumas and timber wolves, that they hunted birds like teratorns and condors to extinction while giving cranes and turkey vultures a pass, which makes no sense; that specific avoidance of humans is a genetic inheritance of co-evolved large mammals that passes down for thousands of generations in the absence of experience, and that intelligent herd mammals already predated upon by bears and the like would allow humans to walk up to members of their herds repeatedly and kill them, painfully, one at a time for generations, and never learn, which is ridiculous.
    Iceaura

    But of course tree dwellers are more vulnerable to fire. They live in trees, which are (mostly) the things that burn! If they leave the trees, they are then totally vulnerable to predators. And there are predators, like raptor birds, that wait outside a fire zone to pick up fleeing animals. When fires are set, forests burn. The tree dwellers in those forests die, or flee into the beaks of predators. We know this, because naturalists have observed, and even filmed this happening. Yet tree dwellers are not the main victims of those waves of extinctions. Large, edible species are the main victims. Your view does not compute.

    The idea of humans killing the cubs of predators like cheetahs, lions and dire wolves is not only realistic, it is demonstrated. There are tribes in Africa doing it to this day! The relevant species in Africa survive because they have been exposed to this kind of attack for a million years and have developed adaptations to permit survival. Like a more powerful nurturing instinct, preventing them from leaving their cubs for long. Nevertheless, certain tribes in Africa will take every opportunity to kill the young of large predators.

    Some raptors go extinct while others survive. Why is this so surprising? Do you know nothing of evolution, which wipes out some species while permitting the 'fitter' species to survive? Some species will be better able to withstand the predation of those primitive humans.

    The same is true for bears, pumas and timber wolves. The fact that they survived shows they were better adapted. Humans could not kill them off via their young because
    1. Bears stay close to their young and protect them
    2. Pumas are secretive and hide.
    3. Timber wolves hide their young in well hidden dens.

    This is not just related to humans, of course. About 3 million years ago, continental drift pushed the two Americas together. When the isthmus of Panama created a land bridge, animals from both Americas moved to the other. A wave of extinctions followed. Animals poorly adapted to tolerating the predatory actions of animals from the other America died out. Other prey species survived because they were better equipped to tolerate the actions of predators. This is documented. I am simply saying that also happened when humans arrived.

    Your suggestion that I claimed herd animals, that had many predators, would allow humans to walk up and kill them is a straw man. Those herd animals, used to predation, were nearly always survivors. That is why bison and herds of deer still run around North America. The ones I suggest did not fear humans, and died due to that lack of fear, were the larger more solitary animals. Like the giant sloth. The giant armadillo. Like mastodons. Those animals would not be used to attacks by predators.

    On the survival of porcupines, raccoons, and possums.
    I suspect that porcupines would not be a favoured prey, because people would soon learn that there is a major hazard in attacking them. Raccoons and possums are more secretive, and will run away and hide.

    Koalas are a very clear cut example of mechanism for survival. They could not survive lots of fires, because they live in trees (not just trees, but the immensely flammable eucalypt! The source of Australia's terrible forest fires!). They are slow, and sleepy during the day. The reason for their survival is clear cut. With a diet of eucalyptus leaves, their flesh is utterly horrible to the taste. The human hunters would soon learn to leave them alone.

    This example alone shows that mass extinctions were not caused by fire.
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    Quote Originally Posted by skeptic
    But of course tree dwellers are more vulnerable to fire. They live in trees, which are (mostly) the things that burn!
    Aboriginal burning of landscapes was mostly of grassland and to maintain savanna or grassland, in Australia and North America. The aborigines in Australia burned by deliberate strategy, on a rotation schedule that covered most of the continent, and rarely burned forest. No one knows if the NA reds were similarly coordinated on that scale, but they did create and maintain very large open savanna and grazing land by regular burning. Prairie fires are more common than forest fires in almost all landscapes, and natural prairie fires tend to be larger than forest fires, spread faster, and offer fewer refuges or chances to escape. And so forth.

    All prairies burn often and easily. They're dry. That's why they're prairies - they dry out, and burn on a landscape scale. Trees need more water and less fire, in general. Even fire adapted trees are adapted to fire frequencies of one or two per century at most - natural prairies burn once or twice a decade.

    Quote Originally Posted by skeptic
    The idea of humans killing the cubs of predators like cheetahs, lions and dire wolves is not only realistic, it is demonstrated. There are tribes in Africa doing it to this day!
    They don't drive anything to extinction that way.

    The idea of them killing to extinction the cubs of cheetahs but not wolves, shortfaced bears but not grizzly bears, lions and leopards but not black bears or wolverines, is what makes no sense. What do we know that all three species of cheetah, the shortfaced bear, and the dire wolf had in common that the grizzly bear, puma, and timber wolf did not? Habitat.

    Quote Originally Posted by skeptic
    The ones I suggest did not fear humans, and died due to that lack of fear, were the larger more solitary animals. Like the giant sloth. The giant armadillo. Like mastodons. Those animals would not be used to attacks by predators.
    Mastodons and mammoths were not solitary. And they did have predators, certainly on their young.

    Quote Originally Posted by skeptic
    I suspect that porcupines would not be a favoured prey, because people would soon learn that there is a major hazard in attacking them.
    There is very little hazard in attacking a porcupine. A child can kill one with a stick in perfect safety. They are slow, and passive.
    Raccoons and possums are more secretive, and will run away and hide.
    Uh, yeah. They hide up there in them trees - like a koala - after sprinting away from these humans they, alone among the edible mammals of North America, have somehow noticed are dangerous.

    Quote Originally Posted by skeptic
    Some raptors go extinct while others survive. Why is this so surprising? Do you know nothing of evolution, which wipes out some species while permitting the 'fitter' species to survive? Some species will be better able to withstand the predation of those primitive humans.
    I just don't see why human hunting is very high on the list of extinction risks for scavenging birds at all, let alone hunting of some but not others.

    A wave of extinctions followed. Animals poorly adapted to tolerating the predatory actions of animals from the other America died out. Other prey species survived because they were better equipped to tolerate the actions of predators. This is documented. I am simply saying that also happened when humans arrived.
    It did not happen in a couple of thousand years. It did not happen without major climate and habitat change. And the role of predation, vs competition and disease, is not established.
    Last edited by iceaura; March 13th, 2012 at 08:37 PM.
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    Iceaura

    Why do you think so much of Australia is grassland, if not the burning of trees? The only places with widespread forest ( before the coming of Europeans who have planted forest) is Tasmania and the tropical north. Both retained forest due to strong rainfall, which kinda stops forest fires. Everywhere there is weaker rainfall, forest is gone, even though modern tree plantings show that trees do quite well there. Trees burn. Australian trees burn exceptionally well. Eucalypts have oil filled leaves. They are pyrophytes which actually 'encourage' forest fires.

    I have already explained the Africa situation. It is different to North America and Australia, and the Pacific, and the Caribbean. It is different because humans evolved there, and the animals humans prey on evolved alongside. The ones that could not tolerate human predation died out hundreds of thousands of years ago. An African model does not reflect the other places because the vulnerable species are long gone.

    I doubt that porcupines are as passive as you think. I have seen them on documentaries, taking strong and rapid action against predators.

    On killing raptors. Humans have always done it, and continue to this day. An example of a rapid extinction is the NZ Haast Eagle which became extinct within 150 years of the arrival of the first humans. This eagle is regarded as the largest eagle ever to have lived. Yet humans killed it off.

    Your comment 'let alone the hunting of some but not others' is a straw man argument, since I did not say that. Humans would hunt all raptors for their feathers, just as the North American native peoples did right up almost to the present. However, some are easier to hunt than others. Those are the ones that go extinct.

    I am afraid your comment about raccoons and possums is just puerile. Not worth answering.
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    Are you saying that the early African natives who evolved in the same environment as the other mammals could not hunt them to extinction but other early humans that migrating to other continents could? Didn't these people all use fire and spears as weapons in Africa and everywhere else on the planet? Regardless it would take a large population growth in humans to create the damage you are implying here as the cause of those extinctions. Humans have had a hard time maintaining their numbers for any long length of time in history before agriculture and that started 10,000 years in its infancy.
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    Are you saying that the early African natives who evolved in the same environment as the other mammals could not hunt them to extinction but other early humans that migrating to other continents could?
    The main difference was in the animal behavior, not the human behavior or technology. Of course we don't know for sure the temperament of the extinct animals, but we do know from more modern examples on islands that animals that don't have long evolutionary experience around humans tend not to be afraid of them.
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    Regardless it would take a large population growth in humans to create the damage you are implying here as the cause of those extinctions.
    No. It only takes the arrival or incursion of a previously unknown predator. New Zealand provides the classic recent example.

    Many of the birds and animals in NZ were passive, not very strong, not at all fleet-footed ground dwellers. It didn't take very many years after the arrival of not very many humans to completely wipe out some species and others are only now being carefully, individual by individual, being nursed back to breeding population size in islands away from humans and their associated animals. Rats, cats, dogs, foxes for starters.

    And someone earlier mentioned water animals not being susceptible to wipe out by humans. I beg to differ. There's more than one Pacific Isalnd which no longer has turtles arriving to breed. As people moved onto these islands, they basically ate every egg they could lay their hands on. Goodbye turtles. And has anyone ever wondered why Europeans went so far out to sea - onto the broad oceans in fact - to fish? Well, that just might possibly be because European rivers and lakes were more or less fished out. The fact that there are still fish around doesn't change the fact that the sizes and quantities of river fish are much less than they once were. Of course, there's the added wondrous benefit of human occupation - rivers that are too polluted for fish of any kind to survive, let alone fish that are safe to eat.
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    My view is that, in terms of vulnerable animals, there are two global areas.
    1. The giant land mass of Europe/Asia/ Africa. Homo erectus had pretty much colonised it all a million years ago.
    2. Oceania, Australia, the Americas, Antarctica, and the islands of the Caribbean and the Indian Ocean. These areas did not see humans or human ancestors till very recently.

    The animals in the first group had time to evolve and adapt to human predation. The animals in the second group did not. Accordingly, when humans arrived in any part of the second region, there were mass extinctions. I do not know why there is any debate, frankly. The relationship is clear cut.

    About New Zealand, adelady is, sadly, quite correct. Within a very short time of the arrival of the first humans, 36 species of native birds were gone. Most from direct human hunting, but a bunch of smaller bird species, like rock wrens, from predation by polynesian rat, introduced by the Maori people.

    To Barbi.

    African natives did, of course, drive species extinct, just as elsewhere in the world. But it happened over a period of million years or more. So it is not as readily apparent. As I said earlier, there were several species of small elephant in Africa a million years ago, as shown by the fossil record. No longer. While we cannot be sure why they went extinct, pre-human hunting must be a prime suspect. Larger elephants are much tougher, and survived.
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    Quote Originally Posted by skeptic
    Why do you think so much of Australia is grassland, if not the burning of trees?
    You can't burn trees unless you have a lot of trees all grown up and ready to burn. Land where trees consistently grow for many years and then get burned off we call "forest". Land where trees do not grow up in big patches ready to burn, but grass grows instead, we call "grassland".

    Obviously, fires set to keep trees out and maintain grassland, clear the snakes away from waterholes, etc, will not kill many koalas - there aren't many in those places.

    Quote Originally Posted by skeptic
    I doubt that porcupines are as passive as you think. I have seen them on documentaries, taking strong and rapid action against predators.
    There is no easier mammal to kill on the North American continent, except maybe a skunk.

    Quote Originally Posted by skeptic
    The animals in the first group had time to evolve and adapt to human predation. The animals in the second group did not. Accordingly, when humans arrived in any part of the second region, there were mass extinctions. I do not know why there is any debate, frankly. The relationship is clear cut.
    The relationship is obvious, the mechanisms and circumstances are not.

    This, for example, is borderline parody - the condors and teratorns were exterminated by being hunted for their feathers?
    Quote Originally Posted by skeptic
    Humans would hunt all raptors for their feathers, just as the North American native peoples did right up almost to the present. However, some are easier to hunt than others. Those are the ones that go extinct
    You have no evidence or argument or ghost of a hint as to why or whether teratorns and condors and the other large scavengers that went extinct would have been easier to hunt than a crane or egret or vulture or eagle or any other large surviving bird. You simply assume that human predation was "the cause" of the human contact extinction wave, and you make shit up about the animals, invent nonsense about trees burning more readily than grass, ignore all of the other factors we know have great influence and all others that are possible, to fit that assumption.
    Quote Originally Posted by adelady
    And someone earlier mentioned water animals not being susceptible to wipe out by humans. I beg to differ.
    On the North American continent, large aquatic and amphibious and wetland animals did not go extinct at nearly the percentage of the large land mammals and larger scavenging birds when humans arrived. This despite their edibility, ease of discovery and kill, and the fact of hunting/fishing pressure.
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    Quote Originally Posted by iceaura View Post
    You simply assume that human predation was "the cause" of the human contact extinction wave, and you make shit up about the animals, invent nonsense about trees burning more readily than grass, ignore all of the other factors we know have great influence and all others that are possible, to fit that assumption.
    You still do not get it, Iceaura.

    Understand.
    We have seen all this in action. There are no secrets. Primitive peoples hunt prey as long as they are hungry. Scientists studying such people observe this again and again. And the results are bloody obvious. What do you think wiped out the moa in my country? They were all gone within 150 years of the arrival of the Maori. Do you think they were gnawed to death by mice?

    What do you think removed the dodo? That is a matter of history and is documented in the ships logs and other reports of the time. It is hunting.

    Certainly other causes are occasionally a part of it. Not all the 2,000 species of birds that went extinct as the Polynesians colonised the Pacific were hunted to death by humans. Many smaller species were killed by the Polynesian rats the Polynesian people brought with them!

    But there is no evidence that forest fires set by people were more than a minor influence on extinctions. Here in NZ, the early Maori wiped out a third of our rain forest with deliberately set fires. Yet the kiwi, the takahe, the weka, the kakapo, and other flightless species, vulnerable to fire, lived on. The species that went extinct were the ones most hunted - the large moa and adzebills. The smaller and more secretive species survived.

    "Making up shit about trees burning more readily than grass?" Another straw man.
    I said that Australian trees were particularly prone to forest fire, which they are. Ask Adelady, who is Australian, about the propensity for eucalypts to catch fire and support raging forest fires. She knows!

    But the evidence we have suggests that human influenced extinctions were almost all due to either overhunting/fishing, or due to introducing other organisms, like the Polynesian rat, as predators, competitors, or pathogens. Fires and climate change are minimal influences, if at all.
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    Quote Originally Posted by skeptic
    We have seen all this in action.
    No, you haven't. You have extrapolated from some stuff you don't understand to a time you don't know enough about, using assumptions you have not checked, and getting your facts wrong all along the way.

    Like this:
    What do you think removed the dodo? That is a matter of history and is documented in the ships logs and other reports of the time. It is hunting.
    More recent investigation blames rats, pigs, and monkeys - and, of course, habitat destruction (loss of the forest cover they apparently preferred for nesting at least).

    Dodos tasted little better than koalas, btw. They weren't hunted much for food.

    Or like this:
    But there is no evidence that forest fires set by people were more than a minor influence on extinctions.
    Nobody is talking about forest fires in particular, except you.
    Here in NZ, the early Maori wiped out a third of our rain forest with deliberately set fires. Yet the kiwi, the takahe, the weka, the kakapo, and other flightless species, vulnerable to fire, lived on. The species that went extinct were the ones most hunted - the large moa and adzebills.
    The large grassland species - the ones most vulnerable to fire and its effects, the slow reproducing and most vulnerable to introduced egg predators, the ones requiring larger ranges etc, vanished; forest and mountain species, a habitat less affected, survived - barely. A similar pattern is visible in NA, only it also involves species almost certainly not hunted much.

    Quote Originally Posted by skeptic
    But the evidence we have suggests that human influenced extinctions were almost all due to either overhunting/fishing, or due to introducing other organisms, like the Polynesian rat, as predators, competitors, or pathogens. Fires and climate change are minimal influences, if at all.
    Expanding from hunting to hunting/fishing plus rats and disease is an improvement. Now some consideration for habitat is in order.
    Last edited by iceaura; March 14th, 2012 at 06:27 AM.
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    Iceaura

    Your fire theory has to explain, not only the animals that went extinct, but also the ones that survived. For example ; look at Australia.
    Two large non venomous snakes extinct. 20 venomous survived. All equally vulnerable to fire. But the hunters would not attack the venomous ones.
    Four large flightless and carnivorous birds extinct. Emu and cassowary, also large and flightless, but herbivore survived. My theory is that the carnivores would run towards the human hunters, and the herbivores away. What is your theory?
    Also extinct = 4 giant echidnas, but not the small burrowing one. 3 giant wombat-like creatures.9 species between 100 and 1000 kg and 22 species between 10 and 100 kg. Smaller animals survived. Why? they would all be vulnerable to fire, but only the larger, better prey species went extinct.
    The same thing happened with reptiles. The large ones extinct (excluding those that could hide from hunters by burrowing or diving into water) which included a giant goanna, a giant turtle, and a fast running land crocodile.

    In addition to all this, we see that there was a second wave of extinctions isolated to Tasmania several thousand years after the first wave in mainland Australia, when a land bridge permitted humans to cross. Yet Tasmania is not prone to fires, since it is too wet. Fires could not have caused the Tasmanian extinctions.

    Here in NZ, there are no grassland species. At least 80% of the land mass was covered with rain forest before the coming of the first humans. Yet the arrival of the Maori wiped out many species of large, flightless forest dwellers, including 11 species of moa, and several species of adzebills - all large and presumably toothsome - while sparing the small flightless forest birds like kiwi, weka, takahe, and kakapo, which were able to hide. Fire had nothing to do with this pattern of extinction. Hunting was all.
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    Quote Originally Posted by Lynx_Fox View Post
    Are you saying that the early African natives who evolved in the same environment as the other mammals could not hunt them to extinction but other early humans that migrating to other continents could?
    The main difference was in the animal behavior, not the human behavior or technology. Of course we don't know for sure the temperament of the extinct animals, but we do know from more modern examples on islands that animals that don't have long evolutionary experience around humans tend not to be afraid of them.
    And it could be another scenario where the earliest humans that had not learned yet to use weapons or even fire were previously considered a non threat to those animals that experienced our earlier ancestors. Since we were not there then, it is only speculation of what might have actually happenned. Are all the species on islands not afraid of humans or a specific few?
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    I don't know why I am trying to diminsh the case of humans being center stage for all those extinctions since I am certainly aware that many species today are hanging on a thin thread to survive that humans are most certainly responsible for their current plight.
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    Quote Originally Posted by Barbi View Post
    And it could be another scenario where the earliest humans that had not learned yet to use weapons or even fire were previously considered a non threat to those animals that experienced our earlier ancestors. Since we were not there then, it is only speculation of what might have actually happenned. Are all the species on islands not afraid of humans or a specific few?
    More than speculation.
    For example : about learning to use weapons and fire.
    Homo habilis, which is an ancestor of ours that lived 2 to 3 million years ago, left fossils associated with chipped stone tool, and beds of ash. In other words, our ancestors more than 2 million years ago had both weapons and fire.

    Fear of humans occurs where there has been predation from humans or human size mammals. Antarctica is a great example. Penguins are afraid of seals, but not of humans. Scientists in Antarctica sit down and have penguins walk up to them and pretty much shove their beaks into the scientist's face.

    Here in NZ, we have a stone age primitive people who killed off the world's largest bird - the giant moa, which stood over 3 metres tall. A single kick from that bird would disembowel a human hunter, but that appears not to have happened. Why not? And why did the entire species (and many others) go extinct in 150 years? Simplest explanation is that they had no fear of mammals, since there was no evolutionary experience with mammalian predators.
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    Quote Originally Posted by skeptic View Post
    Quote Originally Posted by Barbi View Post
    And it could be another scenario where the earliest humans that had not learned yet to use weapons or even fire were previously considered a non threat to those animals that experienced our earlier ancestors. Since we were not there then, it is only speculation of what might have actually happenned. Are all the species on islands not afraid of humans or a specific few?
    More than speculation.
    For example : about learning to use weapons and fire.
    Homo habilis, which is an ancestor of ours that lived 2 to 3 million years ago, left fossils associated with chipped stone tool, and beds of ash. In other words, our ancestors more than 2 million years ago had both weapons and fire.

    Fear of humans occurs where there has been predation from humans or human size mammals. Antarctica is a great example. Penguins are afraid of seals, but not of humans. Scientists in Antarctica sit down and have penguins walk up to them and pretty much shove their beaks into the scientist's face.

    Here in NZ, we have a stone age primitive people who killed off the world's largest bird - the giant moa, which stood over 3 metres tall. A single kick from that bird would disembowel a human hunter, but that appears not to have happened. Why not? And why did the entire species (and many others) go extinct in 150 years? Simplest explanation is that they had no fear of mammals, since there was no evolutionary experience with mammalian predators.
    Your explanation sounds reasonable since we have had first hand experience with these encounters with other species that are not familiar with us but I see a problem with it. If that was the case then it should also apply to any predatory animal that has migrating into new territory where the natives would not know to fear them too. If that is true, then the extinction rate would be extremely high and with shorter periods of existence for that species that is willingly on the menu for that migrating predator.
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    Quote Originally Posted by Barbi View Post
    If that was the case then it should also apply to any predatory animal that has migrating into new territory where the natives would not know to fear them too. If that is true, then the extinction rate would be extremely high and with shorter periods of existence for that species that is willingly on the menu for that migrating predator.
    That deduction is proven correct when we look at the impact of those predators humans have introduced. In New Zealand, the introduction of stoats and rats has been an unmitigated disaster. Small native birds have gone into extinction quite rapidly.

    I believe this to be true also for small native mammals in Australia, with the introduction of foxes. Parks & Wildlife Service - Foxes in Tasmania
    Mongoose in Hawaii. Importers of mongoose ignored voice of caution
    Brown snake in Guam. Brown Tree Snake Could Mean Guam Will Lose More Than Its Birds
    The list goes on.
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    Quote Originally Posted by skeptic
    Your fire theory has to explain, not only the animals that went extinct, but also the ones that survived.
    No. I am not the one proposing one single cause for the extinction wave associated with human incursion into new regions. I am the one pointing to the necessity of including such factors as dramatic and large scale habitat alteration in any discussion of extinctions. I include all habitat alteration - including the Maori effects on the rain forest, the introduction of competing as well as predatory animals and plants, etc.

    For example: You are claiming the dodo was hunted to extinction. I am not claiming the dodo was driven to extinction by fire, merely pointing to evidence and research showing it was subjected to severe pressures from habitat loss and introduced egg predators, and these rather than hunting appear to have been the major factors pushing it to extinction.

    And you keep saying things like this:
    For example ; look at Australia.
    Two large non venomous snakes extinct. 20 venomous survived. All equally vulnerable to fire. But the hunters would not attack the venomous ones.
    Hunters would, did, and do attack venomous snakes. They kind of make a point of it, often - not only for food, but for safety. And no, all snakes are not equally vulnerable to fire, or hunting, or anything else - venomous snakes in my region are more concentrated in sparsely vegetated or other regions where fire is no factor, nonvenomous snakes often run larger and make more rewarding prey and more often share habitat frequented (and burned, etc) by humans, and so forth.

    This is silly. If people are assumed to be making a practice of hiking miles out of their way and devoting days of effort to finding and killing cheetah cubs, which pose almost no threat to humans, or lion and shortfaced bear cubs despite the awful risks of such behavior, they would be very remiss in not finding and killing the egg batches of lethal snakes, eh? How are these hunters picking and choosing in such arbitrary fashion in various places?

    You are the one who needs to explain how hunting alone drove some large mammals and birds we do not know to have been intensively hunted to extinction, while sparing other quite similar animals and birds we know to have been intensively or equally hunted.

    Quote Originally Posted by skeptic
    Four large flightless and carnivorous birds extinct. Emu and cassowary, also large and flightless, but herbivore survived. My theory is that the carnivores would run towards the human hunters, and the herbivores away. What is your theory?
    A few posts back your theory was that large herbivores went extinct because they were incorrigibly tame and would allow hunters to walk up and spear them, over and over for generations. You were arguing that they would not run away, or defend themselves, and that was your explanation for humans being able to exterminate them so quickly by hunting.

    My theory is that human alteration of habitat - such as by depleting the food supply, preferred habitat, and necessary range of large carnivores in various ways - was a critical factor, and normally more significant than direct hunting pressure. In that vein, we observe that many large carnivores need much bigger areas of suitable habitat than large herbivores while competing with humans for prey, and that emus and cassowaries live in wetter and wooded areas (emus migrate to follow rain patterns and prefer open woodlands, cassowaries live in forests) - they were not, in other words, as vulnerable as many other animals were to the fire regime imposed by the aborigines on the Australian landscape.

    Quote Originally Posted by skeptic
    Also extinct = 4 giant echidnas, but not the small burrowing one. 3 giant wombat-like creatures.9 species between 100 and 1000 kg and 22 species between 10 and 100 kg. Smaller animals survived. Why? they would all be vulnerable to fire, but only the larger, better prey species went extinct.
    Lessee: can we think of some reasons a smaller and/or burrowing animal might be less vulnerable to fire, more capable of surviving as a species on smaller remnant patches of otherwise radically altered landscape, and otherwise at some advantage in adjusting to large scale habitat modifications, compared with a much larger and/or non-burrowing one? I can, but I don't want to spoil your fun - give it a try.
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    Are you trying to set a record for maximum number of straw man arguments?

    No, I never said that hunting was the only cause of extinctions, except in New Zealand. Here in my country, habitat loss was minimal. The Maori were a stone age people with very little technology, even of the primitive variety. They certainly did not have the tools to cause widespread habitat loss, and did not. Yet their presence drove 36 species of birds into extinction. The larger ones by hunting and the smaller ones by bringing the Polynesian rat to NZ.

    In Australia, the extinctions happened a long, long time ago, and was of megafauna. You know what mega means? Hunters prefer large prey. Hence the rapid extinction of megafauna. My list was supposed to show you that the waves of extinction had little or no effect on small animals. If they had, like the Maori, brought rats to Australia, the extinctions would have resulted in large scale wiping out of small animals. But they did not, and only larger animals were wiped out. Characteristic of hunting. Any influence of fires, must have been relatively minor, since the small animals survived quite nicely. Not all large animals disappeared, of course. The ones hard to hunt, like fast jumping kangaroos, survived quite nicely.

    I will concede a point about venomous snakes. The reason they were less hunted would be because they were smaller and thus poorer prey - not because they were venomous.

    The following statement :

    "A few posts back your theory was that large herbivores went extinct because they were incorrigibly tame and would allow hunters to walk up and spear them, over and over for generations. You were arguing that they would not run away, or defend themselves, and that was your explanation for humans being able to exterminate them so quickly by hunting."

    is another straw man. The lack of fear was only directed at some, not all prey species. I was talking about North American animals and suggested that some, like mastodons, might be vulnerable due to lack of fear, like the lack of fear Antarctic penguins have towards humans. I also mentioned that frequently hunted animals like bison would react differently, contributing to their continued survival. In the same way, a hunted bird, like the emu, would not lack fear. It would respond to any potential predator by running away.

    Habitat loss through fires would benefit predators, not harm them as you suggest. After all, predators are also scavengers, eating dead carcasses. Fires leave lots of carcasses, and hence more food for meat eaters.

    Re small burrowing animals.
    Have you seen an echidna burrow? I have. It is too shallow to afford an escape from fire. if an echidna relied upon that, it would be roast echidna for the local scavengers.
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    Basically, everyone here thinks that humans are responsible by indirect actions, habitat destruction, introducing evasive species and direct actions, hunting the easier prey that is and all of these combined has caused many extinctions. Our sheer numbers have made us to become a major parasite to the planet.

    According to science, our common ancestor began as a squirrel like creature that evolved into a tree dweller critter who later left for the savannas and walked upright. This eventually gave us the intelligence to evolve weapons which makes us the single most powerful predator on the planet. Our diet started out as a seed or nut consumer, then a fruit consumer, then a scavenger who existed on the remains of dead animals, finally to now eating both fruits, vegetables and meats, fish, etc.

    Also keep in mind that in order for you to be alive today, every line of descent had to manage to stay alive long enough to reproduce the next generation that goes back to the first life on the planet. It is stated that 99% of species are extinct which means their long line of descent ended with their extinction. This leaves us with the mere 1% that have mutated and evolved since the beginning of their long line of descent which are the sole survivors that live today.

    Incredible as this may seem, it is pretty amazing that we started at the bottom of the food chain and managed to evolve to be at the top of the food chain of all of the 1% that is alive today. Before you pat yourself on the back, our success has turned us into the biggest most problematic parasite that this planet has ever seen in its history and we can thank our so called evolved intelligence for making this a reality.

    While many of you believe that technology will solve all these global energy and destructive habitat loss issues for the future survival of our species, it is doubful that it will succeed. The success of this planet's ability to maintain stability depends on all of the members of the biodiversity of the 1% to keep the food chain running efficiently and this means that if we continue on destroying all of the players of the rest of the 1% of species to extinction, the planet is left with only humans.

    At the physics level, this planet is a biochemical conversion machine that depends on a certain number of living biomass to actively convert those biochemicals to maintain life on this planet. From microbes to humans, we are all active contributors in the biochemical conversion process that allows us to live and survive on this planet. If humans manage to end up as the only large mass member to survive, can we make and produce all of the biochemical conversion processes that were performed by all of the members that we drove to extinction? Do the microbes that once lived in all of those creatures also cease to exist or do they continue to exist fighting in competition to live in the human host?

    Is the last players in the game of life end up to be just microbes and humans? Hands down, the microbes are going to end up as the winners.
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    Quote Originally Posted by Barbi View Post

    While many of you believe that technology will solve all these global energy and destructive habitat loss issues for the future survival of our species, it is doubful that it will succeed.
    No.

    The correct statement is that it is Barbi's opinion that it is doubtful it will succeed. Personally, I disagree.
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    I agree, though
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    Anyway the climate change coinciding with these recent extinctions may have been indirectly started by humans. My reasoning: We know that elephants in Africa are largely responsible for maintenance of their preferred grassland habitat, by destroying trees. It seems reasonable to suppose mammoths did the same, in Asia. The albedo difference though, between snow covered steppes and coniferous (evergreen) forest is profound. If hunting depressed mammoth populations to the critical threshold where they couldn't kill trees quickly enough, landscapes would grow beyond "recovery". Moreover the newly established forests drive temperatures up throughout the northern hemisphere. Thus begins a bad spiral for the mammoth.



    Coincidentally I today asked my 11-year-old son how he'd kill a mammoth. He reasoned that since mammoths use their trunks to eat, merely crippling the fleshy tip of that monster's trunk would kill it, by starvation. That hadn't occurred to me, since I was thinking about the meat - but I guess it's better to have starved, exhausted carcass of a wholly mammoth than none at all. I understand orcas employ a similar strategy to kill much larger baleen whales. The child proceeded to devise a baited trap a mammoth reaches into with its trunk, apparently a small hollow in the snow containing grass. From all sides needle-like sticks or bones angle downward and prevent the trunk's removal, or pierce into the soft flesh as the mammoth pulls away. I rather like this solution because our tribes of mammoth killers must have included old ladies and 11-year-old boys besides the daring warriors popularly depicted.
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    Quote Originally Posted by skeptic
    But they did not, and only larger animals were wiped out. Characteristic of hunting. Any influence of fires, must have been relatively minor, since the small animals survived quite nicely. Not all large animals disappeared, of course. The ones hard to hunt, like fast jumping kangaroos, survived quite nicely.
    The fastest and best jumping kangaroos - the large carnivorous ones - went extinct quite rapidly. Smaller animals in general are less vulnerable to habitat loss and resource competition and the like - they need less. If they can burrow, run fast, etc, so much the better when faced with fire.

    Bison in NA - and moose, deer, elk, grizzly bears, black bears, etc - wold have had exactly the same experience with human predation as every other mammal in NA - none.
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    Here is a list of animals in Australia that have gone extinct since the arrival of Europeans.
    List of extinct animals of Australia - Wikipedia, the free encyclopedia

    Note how small they are. This is because recent extinctions had causes other than hunting (mainly the introduction of placental predators). Human hunters target larger prey, as with the earlier list I gave for the extinctions of about 50,000 years ago. The kind of influences you talk about do not target big animals. Big animals are selected as prey by humans, and any that are vulnerable to hunting by humans die out. The vulnerability may be from behaviour. It may be due to slow speed. Or something else. But the small and secretive animals do not go extinct due to hunting. Large, obvious animals do. And the large and obvious animals of 50,000 years ago that went extinct were clearly victims of hunting.

    In North America, some animals went extinct, as they were vulnerable. One cause of vulnerability may have been lack of fear, but please do not twist this into some ridiculous statement that I claim all North American animals of the time lacked fear.

    Another vulnerability may have been solitary nature, or lack of speed, or lack of ability to defend themselves, or lack of hiding habit.

    Many species, of course, would have been less vulnerable to a primitive human hunter with stone tipped weapons and no horses. These ones survived.

    So please do not claim that, because bison, elk and deer, bears and timber wolves, survived, that humans were not actively hunting and killing off vulnerable species.
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    Quote Originally Posted by skeptic
    . The kind of influences you talk about do not target big animals.
    Yes, they do. Habitat loss and resource competition both target large animals, including large carnivores, scavengers, and the like, seldom hunted by humans. That's why islands feature smaller animals, for the most part - restricted habitats favor smaller size. The landscape altering fire regime imposed continent wide on Australia by the aborigines would be expected to have its most severe effects on large grassland and savannah animals, especially carnivores.

    Quote Originally Posted by skeptic
    One cause of vulnerability may have been lack of fear, but please do not twist this into some ridiculous statement that I claim all North American animals of the time lacked fear.

    Another vulnerability may have been solitary nature, or lack of speed, or lack of ability to defend themselves, or lack of hiding habit.
    And you have no reason to presume that any of these factors actually mattered to any given animal in NA at the time, except your presumption that the primary cause of their extinction - the single major factor for all of them - was human hunting.

    So you imagine all kinds of behavioral traits and circumstances, whatever it takes (and often wildly improbable, such as the world's stupidest elephants, or slow and vulnerable large grassland predators), with no evidence individually and no consistency overall.
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    The evidence, iceaura, is what has happened more recently. Obviously we cannot know in detail what happened in North American 12,000 years ago, or in Australia, 50,000 years ago.

    But we do know what has happened more recently, in places like Mauritius and New Zealand. When humans move into a new, and previously untouched area, there is rapid extinction, caused by
    1. for larger animals - hunting
    2. for smaller animals - the introduction of animal aliens.
    This is not some wild idea. It has been measured. In my country, the loss of 11 species of moa had nothing to do with fires, or other habitat destruction. It had everything to do with hungry people slaying flightless birds for food.

    To assume something else for Australia and North America makes little sense. Too many species in Australia, vulnerable to fire, survived, apparently unscathed, while fast running animals that could easily escape fire, died off. Nor is it lack of food. The whole reason aborigines set fire is to encourage new grass, to feed larger numbers of prey animals.

    The loss of species is too damn selective. Large, good food animals, or else predators that might be a risk to human children, get wiped out, while unpalatable animals like koala, and hard to catch animals, like wallabies, survive. Name me a single species of large predator in Australia, big enough to be a risk to humans, that survived. I could name a dozen small predators that are not such a risk, that did. Large predators in Australia were all marsupials, and they did not survive the coming of man.

    North America retained some such predators, but only those that are too formidable for a human with a stone tipped spear to tackle, like grizzlies, or too fast to catch, like wolves and coyotes, or too secretive, like mountain lions.
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    Quote Originally Posted by skeptic
    But we do know what has happened more recently, in places like Mauritius and New Zealand. When humans move into a new, and previously untouched area, there is rapid extinction, caused by
    1. for larger animals - hunting
    2. for smaller animals - the introduction of animal aliens.
    You don't know that. It appears to have been false for the dodo, for example - your example above.
    Quote Originally Posted by skeptic
    This is not some wild idea. It has been measured. In my country, the loss of 11 species of moa had nothing to do with fires, or other habitat destruction. It had everything to do with hungry people slaying flightless birds for food.
    Or eating their eggs.

    Quote Originally Posted by skeptic
    To assume something else for Australia and North America makes little sense.
    Very few of the extinguished animals in NA laid eggs on the ground. And the habitat, landscape, climate, and so forth, changed rapidly just then.
    Quote Originally Posted by skeptic
    North America retained some such predators, but only those that are too formidable for a human with a stone tipped spear to tackle, like grizzlies, or too fast to catch, like wolves and coyotes, or too secretive, like mountain lions.
    And your evidence that dire wolves were slower and not as fierce as timber wolves, shortfaced bears were easier to kill than grizzlies or black bears, cheetahs were less secretive than jaguars, etc, is what exactly?

    The skeletons indicate the opposite.
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    Re the dodo.

    Of course we are not totally sure what killed the dodo. either overhunting or introduction of animal predators. But there is no doubt as to its tameness, as in this quote.

    The last confirmed dodo sighting is the one made on a small islet off Mauritius reported by shipwrecked mariner Volkert Evertsz in 1662:
    "These animals on our coming up to them stared at us and remained quiet where they stand, not knowing whether they had wings to fly away or legs to run off, and suffering us to approach them as close as we pleased. Amongst these birds were those which in India they call Dod-aersen (being a kind of very big goose); these birds are unable to fly, and instead of wings, they merely have a few small pins, yet they can run very swiftly. We drove them together into one place in such a manner that we could catch them with our hands, and when we held one of them by its leg, and that upon this it made a great noise, the others all on a sudden came running as fast as they could to its assistance, and by which they were caught and made prisoners also."

    Eating moa eggs?

    Sure, I agree. Without a doubt, Maori collected moa eggs and ate them, and this contributed to their extinction.

    On the extinction of dire wolves and short faced bear etc.
    Of course we do not know for sure what made them vulnerable. After all, it was around 12,000 years ago, and there were no written records. I could conjecture. But what we do know is that they, and a bunch of other large animals, both predators and animals suitable as human prey animals, died out rather quickly immediately after human arrival. We also know that fast footed animals like deer and bison, plus small and secretive animals did not. The obvious conclusion is that hunting killed them off.

    This argument of yours is like the creationist who argues that evolution cannot be right because we do not know all the mechanisms by which evolution caused change. Denial of the obvious based on a gap in knowledge. If we do not know how humans killed dire wolves, or what the dire wolf vulnerability is, that does not change the fact that dire wolves died out after human arrival, and smaller animals did not.

    I know that you have an emotional commitment to the idea that habitat destruction is a major cause of extinctions. But the data does not support this.


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    Quote Originally Posted by skeptic View Post
    And why should a giant beaver not be in the same region as a deer?
    Why imagine giant beavers in North America ....

    2-Cat-giant-beaver.jpg

    .... when we have actual capybaras in South America (which is also home to various deer)

    capybara_picdump-147.jpg
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    And of course, in South America, you had your own set of megafauna extinctions.



    Picture of people, 10,000 years ago, hunting a now extinct glyptodon.
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    Quote Originally Posted by skeptic
    Of course we are not totally sure what killed the dodo. either overhunting or introduction of animal predators.
    But we have research and evidence, which points to habitat destruction and egg - not adult - predation.
    Quote Originally Posted by skeptic
    On the extinction of dire wolves and short faced bear etc.
    Of course we do not know for sure what made them vulnerable. After all, it was around 12,000 years ago, and there were no written records. I could conjecture. But what we do know is that they, and a bunch of other large animals, both predators and animals suitable as human prey animals, died out rather quickly immediately after human arrival. We also know that fast footed animals like deer and bison, plus small and secretive animals did not. The obvious conclusion is that hunting killed them off.
    The only problem being that the observation is not true (many of the survivors were slower footed and less secretive than the extinguished ones) and the conclusion is not obvious or well supported by evidence - the animals vanishing included the fastest, fiercest, and least likely hunting targets as well as more reasonable prey animals in apparently random assortment, and the survivors share nothing in particular except an apparent tendency to be less habitat specific, and smaller (less habitat needed). We don't know how destructively they hunted, but we do know, for a fact, that the Reds altered the landscape by fire and resource competition on a large scale. So - - hunting? A factor, surely, but hardly an explanation in itself.
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    Re the dodo.
    We have direct accounts of sailors killing them for food. Documented. I agree other factors may have been involved, but habitat destruction was minimal up to the time of dodo extinction, and could only have been a very minor contributor. More important would be the introduced alien animals.

    North American extinctions were not caused by habitat destruction. For a start, the sheer area of land involved was too great. it was essentially impossible for those primitive peoples to destroy the natural habitat everywhere. Within a relatively short period of time, trees and forest have a habit of growing back!

    Also we see that when the first Europeans got there, the natural habitat was substantially untouched. And finally, the worst habitat destruction was natural - due to warming at the end of the last glacial period. And we know that all the animals that became extinct when humans arrived survived nine other warmings, over the previous million years.

    Anthropologists and historians generally have two theories for the extinctions.
    1. Humans killed the megafauna by hunting.
    2. Climate change.

    I am personally convinced that the climate change idea is wrong, simply because they all survived 9 other warmings. The difference about the latest warming is that humans arrived. The logical conclusion is that hunting is the major cause of megafauna extinctions in North America, South America, Australia and New Zealand.

    I would suggest that you do not use the term 'the Reds'. They were native Americans. The only reason for the name 'Reds' was the early observation of some tribes that adorned their faces with red ochre. That was never more than a small part of the sum total of tribes, and the natural skin colour of native Americans is most definitely not red.
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    Quote Originally Posted by skeptic
    I agree other factors may have been involved, but habitat destruction was minimal up to the time of dodo extinction, and could only have been a very minor contributor
    You are wrong about that, as about the majority of other factual assertions you have made on this thread.

    You should at least check on this stuff - it isn't that difficult: for example, your original assertion that the dodo was driven extinct by human hunting and hunting only was a five second Wiki search from better information.
    Quote Originally Posted by skeptic
    North American extinctions were not caused by habitat destruction. For a start, the sheer area of land involved was too great. it was essentially impossible for those primitive peoples to destroy the natural habitat everywhere.
    Such exaggerated destruction is neither claimed or necessary. The landscape of Australia, Europe, and North America was modified by humans on a continent wide scale, even if only fire is considered - easily enough to put large mammals with specific habitat requirements, and the ecosystems supporting them, already restricted by climate change, under severe pressure.

    Quote Originally Posted by skeptic
    Also we see that when the first Europeans got there, the natural habitat was substantially untouched
    This is the kind of stuff you need to check before posting. The discussion would be much improved if crude factual errors repeatedly asserted in more or less complete ignorance were simply omitted from it.
    Last edited by iceaura; March 22nd, 2012 at 09:55 PM.
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    Iceaura

    You make broad claims without evidence.
    For example : you ignore the fact that the forest in Mauritius was little harmed by the time dodos became extinct. The time between discovery of the dodo and its final extinction was less than 80 years. That rapid extinction is not characteristic of habitat destruction (a lot of the forest cover in Mauritius was intact long after the dodo was gone). It is characteristic of hunting, by people and by introduced animals.

    On fire destroying the habitat in North America, Australia and South America.
    Not a credible assertion. Those are vast areas. Fires can destroy small parts, sure. But the forest and the grasslands grow back, and the mobile animals avoid the fire. A primitive, stone age culture simply has not the capability of destroying enough terrain for mass extinctions. But they can hunt animals to extinction, if those animals are vulnerable.

    The animals that went extinct included a lot that are not vulnerable to fire. That is : animals that are mobile, and can move away from areas of fire and the aftermath of fire. The animals that did not go extinct include a lot that are vulnerable to fire. Particularly small forest dwellers.

    If fire is the problem, why did large carnivorous birds go extinct in Australia, and large herbivorous birds not go extinct? My explanation for that is fear. The herbivores fled human hunters, and the carnivores did not. But fire would have affected them both. In fact, fire would help the carnivores, since it leaves a trail of animal corpses.

    Several large and edible snakes went extinct, and the smaller ones did not. Fire would have killed them all. However, if hunting was the problem, the ones to die would be the conspicuous ones, while the secretive ones would survive.

    Fires are a major and frequent event to this day in Australia, and appears not to wipe out any animal populations, including the slow moving and very vulnerable koala. If hunting was the cause of extinctions, the survival of the foul tasting koala is easily explained.

    Your fire explanation does not explain the selective nature of the extinctions. Fire and habitat loss does not make sense. Hunting does.
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    Quote Originally Posted by skeptic
    For example : you ignore the fact that the forest in Mauritius was little harmed by the time dodos became extinct.
    The researchers who debunked the hunting only hypothesis, years ago, say otherwise. Try Wiki.
    Quote Originally Posted by skeptic
    On fire destroying the habitat in North America, Australia and South America.
    Not a credible assertion.
    I said nothing about fire destroying "the habitat", and nothing about fire destroying anything in South America, and so forth. All you have to do is read what I posted, to see that.

    Why do you post like that? Do you not read, are you deliberately trolling, or what is your problem?

    Quote Originally Posted by skeptic
    Those are vast areas. Fires can destroy small parts, sure. But the forest and the grasslands grow back, and the mobile animals avoid the fire.
    Fire was used to more or less permanently alter the landscape and ecosystems over huge areas - ten of thousands of square miles - of North America, and almost the entire continent other than outright desert and rain forest of Australia. Deforestation by other means and for other reasons altered Europe.

    Quote Originally Posted by skeptic
    If fire is the problem, why did large carnivorous birds go extinct in Australia, and large herbivorous birds not go extinct?
    Good question. One possible answer, which fits the evidence and is consistent throughout: The carnivorous birds lived in areas frequently burned, in habitats vulnerable to fire, needed large ranges, and competed with humans for food. None of that is true of the forest dwelling herbivorous birds.

    Have you discarded your assumption that large herbivores (especially birds, like the dodo or the moas of New Zealand) without experience of human predation would be tame and vulnerable?
    Quote Originally Posted by skeptic
    My explanation for that is fear. The herbivores fled human hunters, and the carnivores did not
    And the carnivores were incapable of learning, lived in no refugia, and did not protect their nests or hide them - unlike the herbivores? Meanwhile, in North America, herbivores were without fear, and large carnivores (pumas, grizzlies, black bears, timber wolves, wolverines, ) were hiding and fleeing.

    Quote Originally Posted by skeptic
    Several large and edible snakes went extinct, and the smaller ones did not. Fire would have killed them all.
    Again, this kind of ignorant bs should be simply omitted. There is no reason anything - fire, hunting, anything - would affect all snakes the same, large snakes the same as small ones in general, and so forth. "Fire would have killed them all" is just stupid. Why do you post like that?

    Quote Originally Posted by skeptic
    The animals that went extinct included a lot that are not vulnerable to fire.
    Really? Name them.

    The animals that went extinct seem to have been predominantly those whose habitat needs were large, and whose preferred ecological range and resource base was much altered by humans (especially but not exclusively by fire).
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    Quote Originally Posted by iceaura View Post
    I said nothing about fire destroying "the habitat", and nothing about fire destroying anything in South America, and so forth. All you have to do is read what I posted, to see that. .
    Your explanation for the mass extinctions in Australia and North America has been habitat destruction, and you talk of fire being set by the early human inhabitants. Or have you changed your mind?

    On South America, the mass extinctions of megafauna continued. Do you have an alternate explanation? Perhaps over-hunting?

    Carnivorous birds died out because they lived in flammable areas? Herbivorous did not?
    Are you aware than emus live right across Australia, including the grasslands? After you specifically talked of fire in grasslands.

    You said :

    "Have you discarded your assumption that large herbivores (especially birds, like the dodo or the moas of New Zealand) without experience of human predation would be tame and vulnerable?"


    For the dodo it is not an assumption. It is a clearly documented report from those who saw it. We see the same in Antarctica today with all species of penguin. For the moa, it is inferred, since a 3 metre bird with enormously powerful legs would be very hard to kill by a stone age people with no metals, or bow and arrow, or other serious weapons, if they were not tame. Yet they died out in 150 years. Totally.

    Do I believe carnivores are incapable of learning?
    As individuals, no. As a species, yes, without thousands of years, which they did not have, to evolve new behaviour.

    Fire killing all snakes.
    If fire was the primary cause of the megafauna extinctions in Australia, it would have to be widespread. If it killed two snake species, it would kill all. However, if hunting was the cause, then it would be more selective. The large and obvious species would die out quickly. Which they did.

    In the last line you now say "not exclusively by fire". perhaps you would like to be more specific. In what way would a stone age people destroy the wider habitat without fire? Would they take their chainsaws to the trees?

    Animals that went extinct that were not vulnerable to fire would include the fast moving ones, like the carnivorous flightless birds and the carnivorous giant kangaroo. It is easy to explain their extinction, in spite of being less vulnerable to fire, if you accept the lack of fear towards humans, combined with vigorous human hunting.
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    Human hunting remains the most parsimonious explanation for megafauna extinctions shortly after their arrival at multiple locations. Some related research is exploring the roles of super predators in different environments. We certainly qualify as one.
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    Quote Originally Posted by skeptic
    Your explanation for the mass extinctions in Australia and North America has been habitat destruction, and you talk of fire being set by the early human inhabitants. Or have you changed your mind?
    Your assertion that I claimed the South American extinctions were due to fire setting is false. Your claim that I ascribe mass extinctions to "destruction of the habitat" is false. Your continual posting of false assertions about my posts is offensive trolling. Stop doing that, and we can have a discussion about the thread topic - starting with your many false assertions there.

    Quote Originally Posted by skeptic
    Carnivorous birds died out because they lived in flammable areas? Herbivorous did not?
    Emus and cassowaries live and lived in forested areas. There were no carnivorous birds specifically discussed in my post - the reference was to large Australian carnivores going extinct during human settlement of Australia, and these included kangaroos, land crocodiles, etc. They lived in areas the aborigines burned and radically altered, and they needed large ranges of suitable habitat.

    Your assertions that animals living in forested areas are more vulnerable to Australian aborigine fire setting was false. Your argument that many different kinds of moas died out because they were tame, while emus and cassowaries did not because they were not tame, has no evidence or reasoning to support it. And so forth.

    Quote Originally Posted by skeptic
    Are you aware than emus live right across Australia, including the grasslands?
    My claim that emus live in forests was completely accurate, as was my observation that large, edible, frequently hunted forest dwellers in Australia were more likely to have survived the human settlement than large, less edible, less frequently hunted savanna and grassland dwellers.
    Quote Originally Posted by skeptic
    Animals that went extinct that were not vulnerable to fire would include the fast moving ones, like the carnivorous flightless birds and the carnivorous giant kangaroo. It is easy to explain their extinction, in spite of being less vulnerable to fire,
    They were more, not less, vulnerable to fire-setting habitat loss - they needed more range, they were competing in their shrunken habitat for food with a new predator, they reproduced (repopulated) more slowly, and so forth.
    Quote Originally Posted by skeptic

    For the dodo it is not an assumption. It is a clearly documented report from those who saw it
    Your assertion that the dodo was hunted to extinction is contradicted by research. It appears to be false.
    Quote Originally Posted by skeptic

    Do I believe carnivores are incapable of learning?
    As individuals, no. As a species, yes,
    My assertion was that all large social mammals are capable of learning, and teaching their young. A more appropriate response from you would be to point out that humans can kill them anyway, not that they can't easily and rapidly learn to avoid humans. Two or three different kinds of bison learned, black bears learned, grizzlies learned, moose learned, pronghorns learned, two or three different kinds of deer learned, timber wolves learned, pumas learned, and so forth.

    And they unlearn, equally rapidly. The deer in suburbs near my house lie around in people's yards like cows, unless a dog is present. The moose on Isle Royal calve and raise their young by preference near human occupation, and wander by within easy spear throw so often that park personnel have to warn hikers against approaching one of the calves to pet it. Bears and lions and pumas and wolves and deer and so forth are quite tame if raised in the company of benign humans - no "genetic" avoidance or hostility is visible, to explain their survival of the great extinction event in NA.
    Quote Originally Posted by skeptic
    If fire was the primary cause of the megafauna extinctions in Australia, it would have to be widespread. If it killed two snake species, it would kill all.
    Now you are just being silly.
    Quote Originally Posted by skeptic
    In what way would a stone age people destroy the wider habitat without fire?
    Gardening is one well documented - there were places in the Eastern forest of North America where 85% of the standing timber was American Chestnut trees, and the forest was open beneath them. It's easy to kill a tree with a stone tool, btw - girdle it.
    Quote Originally Posted by skeptic
    For the moa, it is inferred, since a 3 metre bird with enormously powerful legs would be very hard to kill by a stone age people with no metals, or bow and arrow, or other serious weapons, if they were not tame.
    Their eggs, on the other hand, were not so well equipped - and an atlotl launched spear is capable of killing much larger and more dangerous or elusive prey than a moa sitting on a nest (the NA Reds killed ton-weight horned bison with them). If you are going to seriously argue a hunting only hypothesis, underestimating the hunting ability of aboriginal people is a poor start.

    Quote Originally Posted by lynx
    Human hunting remains the most parsimonious explanation for megafauna extinctions shortly after their arrival at multiple locations.
    Only if it actually explains anything, and bears up under more careful investigation. So far, the common and initial ascription of extinction primarily to overkill by subsistence hunters has not been borne out in very many of the cases in which careful investigation was possible - the dodo, the passenger pigeon, the severely depleted large birds of NA, and so forth. It holds weight still primarily in arenas we don't know much about.

    Hunting for money has wiped out whole species, especially those confined to significantly smaller habitats than they evolved to fit, but subsistence? That's different.
    Last edited by iceaura; March 23rd, 2012 at 07:31 PM.
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    Iceaura

    You accuse me of being inaccurate. Your 'factual statements" are worse.

    For example : emus are not forest birds particularly. They can live in forest, but also almost anywhere else. i have seen them on beaches, on farm land, in scrub, and even walking through a town. Wild birds. Here is proof. (my photo)



    On hunting moa.
    Maori did not have atlatl's. They did not even have stone tipped spears. Their most lethal weapon was a carved length of timber, which functioned much like a quarter staff. They had every incentive to develop weapons, since inter-tribal warfare was rife, and vicious. But they never developed any kind of projectile weapon. So I am afraid your lack of knowledge makes your comments on hunting moa unreliable and inaccurate.


    You appear to be hung up on habitat destruction. That is your personal thing that leads you into wrong ideas. The scientists that study megafauna extinctions of the past tend to ascribe it to over-hunting or climate change. I have explained why climate change is not credible. That leaves over-hunting.

    However, I am going to stop arguing this with you. Eventually, bashing my head against a brick wall leaves with with a sore head.
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    Before I finally quit, one last reference.

    Big Kill, Not Big Chill, Finished Off Giant Kangaroos: Scientific American

    I quote :

    "Humans could have hunted them to extinction or set fires that changed the landscape so much that large herbivores could not survive. But examining the core in 100-year increments showed that the shifts in vegetation happened after the near disappearance of Sporormiella spores—not before as would have been expected if fire-triggered vegetation changes had caused the extinctions. "It could not have been vegetation change due to firing of the landscape, as other people have proposed, because those things followed megafaunal decline," Johnson argues.

    In fact, the disappearance of the big plant-eaters seems to have set the stage for fires, allowing the buildup of the dry grasses and other fine fuels that spur burning like the catastrophic wildfires still seen in Australia today."


    And also from the same article.

    "Extinctions in other parts of the world were remarkably similar in pattern and severity to those that occurred in Australia," he notes. After all, human hunting wiped out similar species from in neighboring New Zealand less than a millennia ago. "This seems to strengthen the view that human impact—mainly hunting—was the predominant cause in other places as well as in Australia."


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    Although there are other hypothesis, at least for Australia and the Americas the incidence of the extinction of the largest animals would seem to have been coincident with the introduction of humans into these continents. We know in the old world that humans hunted mamoths for instance. Since we're only talking about the largest animals human predation is thought by many to be the most likely possibility, even though climate changes during and after the last ice age and volcanism may have also contributed to these extictions in some areas.
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    Quote Originally Posted by iceaura View Post
    Quote Originally Posted by lynx
    Human hunting remains the most parsimonious explanation for megafauna extinctions shortly after their arrival at multiple locations.
    Only if it actually explains anything, and bears up under more careful investigation. So far, the common and initial ascription of extinction primarily to overkill by subsistence hunters has not been borne out in very many of the cases in which careful investigation was possible - the dodo, the passenger pigeon, the severely depleted large birds of NA, and so forth. It holds weight still primarily in arenas we don't know much about.
    It fact I said "most," appropriately caveats my statement. I'm not claiming it explains "everything." If human impacts, mostly by hunting, seems to explain what we know and matches the observational evidence we have so far.

    ....in arenas we don't know much about
    Until we get better hypothesis that's even more parsimonious, better observational evidence, or both...the scientific method leans on the simplest explanation--that of humans hunting. If you want to think of the infinite range of other far more complex or unsupported ideas than you are going beyond science and into philosophy (i.e., mental masturbation).

    Hunting for money has wiped out whole species, especially those confined to significantly smaller habitats than they evolved to fit, but subsistence? That's different.[/QUOTE]
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    Quote Originally Posted by lynx
    It fact I said "most," appropriately caveats my statement. I'm not claiming it explains "everything." If human impacts, mostly by hunting, seems to explain what we know and matches the observational evidence we have so far.
    The appropriate caveat would be "some, maybe". As should be clear by the "arguments" (benefit of charity) offered above in every specific case carefully considered from the dodo on, it does not explain what we know, and matches the evidence only when we have very little.

    Quote Originally Posted by lynx
    Until we get better hypothesis that's even more parsimonious, better observational evidence, or both.
    The attempt to be "parsimonious" in that sense seems to be a fundamental error of approach, on both theoretical and evidentiary grounds.

    Quote Originally Posted by lynx
    .the scientific method leans on the simplest explanation--that of humans hunting.
    The scientific method leans on no such thing, and human hunting would not qualify anyway - it's not a simple factor. It does not even explain (in itself, without reference to habitat etc) the pattern of extinctions that is the bulk of the evidence we have (teratorns and cheetahs and shortfaced bears are wildly unlikely targets of stone age hunting pressure compared with cranes and moose and black bears, for example).
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    Still ignoring evidence, Iceaura?
    Check post 79.
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    This is only a report of a summary. But for those interested, it seems that it's hunting and climate change - one, the other, or both in concert - that led to most of the extinctions of megafauna. Getting hold of the whole paper might be worth the effort.

    Demise of early large animals caused by both humans and climate change
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    Quote Originally Posted by lynx
    It fact I said "most," appropriately caveats my statement. I'm not
    claiming it explains "everything." If human impacts, mostly by hunting,
    seems to explain what we know and matches the observational evidence we
    have so far.;
    The appropriate caveat would be "some, maybe". As should be clear by the "arguments" (benefit of charity) offered above in every specific case carefully considered from the dodo on, it does not explain what we know, and matches the evidence only when we have very little.
    Quote Originally Posted by lynx
    Until we get better hypothesis that's even more parsimonious, better observational evidence, or both.
    The attempt to be "parsimonious" in that sense seems to be a fundamental error of approach, on both theoretical and evidentiary grounds.
    Quote Originally Posted by lynx
    .the scientific method leans on the simplest explanation--that of humans hunting.
    The scientific method leans on no such thing, and human hunting would not qualify anyway - it's not a simple factor. It does not even explain the pattern of extinctions (teratorns and cheetahs and shortfaced bears are wildly unlikely targets of stone age hunting pressure compared with cranes and moose and black bears, for example).

    Quote Originally Posted by skeptic
    Still ignoring evidence, Iceaura?
    Check post 79.
    Not ignoring evidence, disagreeing with argument.

    That it might take a couple of hundred years for a burning regime to permanently alter the vegetation is not surprising, is it ? That's very quick.

    Neither is a loss of fungal spores from large, combustible piles of dung.

    Or are we assuming that aborigines did not bring their fire setting practices with them, and only started firing the landscape after it had been adapted coincidently to regular firing by the loss of grazing animals?
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    The attempt to be "parsimonious" in that sense seems to be a fundamental error of approach, on both theoretical and evidentiary grounds.
    It is how science works though.
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    Another hypothesis could also be correct. After supposedly the third major wave of humans migrated from the middle east originating from Africa, modern humans co-existed with Neanderthals, but not for long until the Neanderthals became extinct. Neanderthals might also be classified as large mammals. Some believe their demise was also an act of modern human predation. Of course there are many other possible reasons for the demise of the Neanderthals. Some reasons why modern humans could have done them in are: predation, simply to eliminate the competition for food, wars for booty, territorial wars like chimps for land, shelter, caves, etc., an act of discrimination to eliminate those that for religious or cultural reasons were different from them, simply for the fun of killing or the right of passage into manhood , Neanderthals moving to less desirable and harsh climates to avoid modern humans, or a combination of these "possibilities."

    Although most depictions of Neanderthals were of a brutish appearance, according to modern DNA studies Neanderthals had the ginger gene which modern humans out-of-Africa did not have. This would have given Neanderthals reddish colored hair and also possibly lighter colored skin also because of this same gene which might have provided Neaderthals with better cold-whether adaptation resulting in better vitamin D sun absorption. This may have been sexually attractive to some modern humans resulting in a possible additional killing motivation. The booty for a raid would have been "attractive" Neanterthal women, adolescents, and young children. Limited skeletal remains and genetic studies, however, presently seem to suggest that only limited interbreding with modern humans took place.
    Last edited by forrest noble; March 27th, 2012 at 02:56 AM.
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    i think that the answer of your question is right because there is also a large mammals over a past of a years.and its a fact that the over a 10000 years ago the large mammals have been lost.almost round about 50 percent of a large mammal species are lost...in these mammals there are the mammoths,mastodons,giant ground sloths etc.
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    Quote Originally Posted by forrest noble View Post
    Another hypothesis could also be correct. After supposedly the third major wave of humans migrated from the middle east originating from Africa, modern humans co-existed with Neanderthals, but not for long until the Neanderthals became extinct. Neanderthals might also be classified as large mammals. Some believe their demise was also an act of modern human predation. Of course there are many other possible reasons for the demise of the Neanderthals. Some reasons why modern humans could have done them in are: predation, simply to eliminate the competition for food, wars for booty, territorial wars like chimps for land, shelter, caves, etc., an act of discrimination to eliminate those that for religious or cultural reasons were different from them, simply for the fun of killing or the right of passage into manhood , Neanderthals moving to less desirable and harsh climates to avoid modern humans, or a combination of these "possibilities."

    Although most depictions of Neanderthals were of a brutish appearance, according to modern DNA studies Neanderthals had the ginger gene which modern humans out-of-Africa did not have. This would have given Neanderthals reddish colored hair and also possibly lighter colored skin also because of this same gene which might have provided Neaderthals with better cold-whether adaptation resulting in better vitamin D sun absorption. This may have been sexually attractive to some modern humans resulting in a possible additional killing motivation. The booty for a raid would have been "attractive" Neanterthal women, adolescents, and young children. Limited skeletal remains and genetic studies, however, presently seem to suggest that only limited interbreding with modern humans took place.
    How do you explain all the modern humans with red hair and light skin?
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    Quote Originally Posted by Barbi View Post
    Quote Originally Posted by forrest noble View Post
    Another hypothesis could also be correct. After supposedly the third major wave of humans migrated from the middle east originating from Africa, modern humans co-existed with Neanderthals, but not for long until the Neanderthals became extinct. Neanderthals might also be classified as large mammals. Some believe their demise was also an act of modern human predation. Of course there are many other possible reasons for the demise of the Neanderthals. Some reasons why modern humans could have done them in are: predation, simply to eliminate the competition for food, wars for booty, territorial wars like chimps for land, shelter, caves, etc., an act of discrimination to eliminate those that for religious or cultural reasons were different from them, simply for the fun of killing or the right of passage into manhood , Neanderthals moving to less desirable and harsh climates to avoid modern humans, or a combination of these "possibilities."

    Although most depictions of Neanderthals were of a brutish appearance, according to modern DNA studies Neanderthals had the ginger gene which modern humans out-of-Africa did not have. This would have given Neanderthals reddish colored hair and also possibly lighter colored skin also because of this same gene which might have provided Neanderthals with better cold-whether adaptation resulting in better vitamin D sun absorption. This may have been sexually attractive to some modern humans resulting in a possible additional killing motivation. The booty for a raid would have been "attractive" Neanderthal women, adolescents, and young children. Limited skeletal remains and genetic studies, however, presently seem to suggest that only limited interbreeding with modern humans took place.
    How do you explain all the modern humans with red hair and light skin?
    Although such evolution might have originated from Neanderthals I would expect that it is an example of co-evolution. Present theory has it that man and animals as a cold climate adaptation accordingly evolved lighter skin/ white fur, blue eyes, through the albinism genes which is an infrequent mutation in all mammals allowing for polar bears, arctic wolves, white foxes, white humans, etc. The red hair and blue eyes related to albinism are presently thought to be just a side effect. "White" skin in humans might have been a better camouflage than black in northern latitudes, but again increased vitamin D and heat absorption from less melanin in the skin could compensate for less solar radiation. For animals the primary advantage for such genes was probably camouflage. After the first such mutation(s) sexual selection for appearance was also probably involved in both animals and humans as well as healthier humans/ animals can produce more offspring.

    The human evolution of being generally fur-less ("hair-less") is thought to have been an African adaptation like elephants, rhinos, hippos, which enables an animal to more quickly lose body heat when foraging on the African plain. For humans the advantage of such heat reduction seemingly could improve endurance when running and hunting, and to reduce body lice and some parasites. Again sexual selection may have quickly increased the frequency of this mutation as well as improved survivability of off-spring. The increased height and weight of humans is probably based upon prosperous male dominated hunting and waring cultures.
    Last edited by forrest noble; March 27th, 2012 at 01:14 PM.
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    That and the fact that genetic studies show than non-African modern humans interbred with Neanderthals and Denisovians (possibly another).
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Quote Originally Posted by forrest noble View Post
    For humans the advantage of such heat reduction seemingly could improve endurance when running and hunting, and to reduce body lice and some parasites.
    Perhaps Forrest, you might explain why it is that no other terrestrial mammal in our size range has lost hair as humans did? Surely, if there was such a wonderful advantage in endurance and in parasite control, other animals would also have evolved in that direction.

    The thing is that hair is not a detriment. It is a vitally important source of thermal insulation, that cannot be dumped in that cavalier way.
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    Is there fossils of modern mammals that date back at the same time as the other larger mammals that existed?
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    Quote Originally Posted by Barbi View Post
    Is there fossils of modern mammals that date back at the same time as the other larger mammals that existed?
    Which prehistoric large mammals are you referring to Barbi?
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

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    Quote Originally Posted by skeptic View Post
    Quote Originally Posted by forrest noble View Post
    For humans the advantage of such heat reduction seemingly could improve endurance when running and hunting, and to reduce body lice and some parasites.
    Perhaps Forrest, you might explain why it is that no other terrestrial mammal in our size range has lost hair as humans did? Surely, if there was such a wonderful advantage in endurance and in parasite control, other animals would also have evolved in that direction.
    Both elephants and rhinos had hairy ancestors/ relatives in colder climates. The fact that the African varieties do not, I think is a clue. African elephants also have bigger ears also thought to be a cooling advantage like jack rabbits and African wild dogs. Body hair has both advantages and disadvantages. In an environment where the disadvantages outweigh the advantages, genetic changes can take place concerning the survival of the fittest.

    Fossilized evidence indicates that humans were primarily hunter gatherers when body hair loss is believed to have evolved, and probably these human ancestors were not arboreal dwelling like chimps. They probably lacked the strength to climb like chimps, they were hunter gatherers and plains dwellers, probably residing near streams or lakes. Here is a link explaining the hypothesis that body hair loss could be more efficient for faster running hunters.

    Hair we go: Why we lost our locks so we could run faster to catch food | Mail Online

    Here's another link for the hypothesis involving parasite control advantages of humans losing body hair.

    Do Humans Lack Body Hair to avoid Parasites? - Ancient History Blog

    And again another hypothesis involving human body hair loss could have also been perpetuated for sexual selection reasons, regardless of the primary advantage that such a mutation might bestow.

    Sexual selection in human evolution - Wikipedia, the free encyclopedia

    The thing is that hair is not a detriment. It is a vitally important source of thermal insulation, that cannot be dumped in that cavalier way.
    If ancient man had a lifestyle as a hunter gatherer primarily on the plains of Africa, then some genetic changes could have been an advantage over their ancestor's arboreal traits. The theory is that the loss of most human body hair was one of these adaptations.
    Last edited by forrest noble; March 28th, 2012 at 12:31 AM.
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    Quote Originally Posted by Paleoichneum View Post
    Quote Originally Posted by Barbi View Post
    Is there fossils of modern mammals that date back at the same time as the other larger mammals that existed?
    Which prehistoric large mammals are you referring to Barbi?
    Was the saber tooth cat fossils found along side a modern cat fossil or other modern mammal that share the same date of their fossils?
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    Quote Originally Posted by Barbi View Post
    Quote Originally Posted by Paleoichneum View Post
    Quote Originally Posted by Barbi View Post
    Is there fossils of modern mammals that date back at the same time as the other larger mammals that existed?
    Which prehistoric large mammals are you referring to Barbi?
    Was the saber tooth cat fossils found along side a modern cat fossil or other modern mammal that share the same date of their fossils?
    In that case then yes, extant and extinct species have been recovered from sediments of the same age.
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

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    Quote Originally Posted by Barbi View Post
    Quote Originally Posted by Paleoichneum View Post
    Quote Originally Posted by Barbi View Post
    Is there fossils of modern mammals that date back at the same time as the other larger mammals that existed?
    Which prehistoric large mammals are you referring to Barbi?
    Was the saber tooth cat fossils found along side a modern cat fossil or other modern mammal that share the same date of their fossils?
    The saber tooth tiger, or Smiladon, was a more modern north American cat evolving about 2.5 million years ago, probably from the American panther. They became extinct only about 10,000 years ago when other large animals also became extinct. The American mountain lion/ cougar is related to the Asian variety, which was believed to first cross the Bearing straight about 8 million years ago. It shared much of the same territory as the saber toothed tiger but was smaller and generally hunted smaller animals. At the La Brea tar pits in southern California, both species were found about the same fossil age at this same location. Whether they competed often at the same time in the same location is a matter of conjecture, but most believe that when they did, they generally did not compete for the same prey. Saber cats generally hunted larger animals. Cougars would have been very leary of saber toothed cats not just because they were bigger, but because they were not solitary hunters like cougars but ran in packs more like African lions.

    10,000 years ago when the saber tooth tigers became extinct man was at that time or soon thereafter, first entering South America in very small numbers. Therefore man, at that time, could not have been the cause of the Smilodon's extinction by the competition of over-hunting large game. Instead the most likely cause of these extinctions in South America (thought to be the origin of the Smiladons) at the end of the last ice age was changing climates. From 12,000 to 10,000 years ago was the end of the glacial period where decreasing land and sea temperatures were related to rising lake and ocean levels caused by melting and retreating glaciers. Not only did temperatures accordingly decrease in some areas of the Americas but rainfall patterns were generally disrupted everywhere. Some areas becoming drier and others became wetter with freezing temperatures. This is not a good environment for plants that had been readjusting to warmer climates in some areas. Animals that fed on these plants would have also been greatly stressed, especially the larger herbivores that required more food and eventually the largest predators that fed on them such as the Smilodons.

    These same temperature disruptions were world wide which also stressed both plants and animals. Most of these larger animal species around the world did not make it to the modern warming period after surviving for millions of years through other ice ages and predation.

    http://en.wikipedia.org/wiki/Quatern...tinction_event
    http://anthro.palomar.edu/homo/homo_3.htm
    Last edited by forrest noble; March 28th, 2012 at 02:27 AM.
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    Quote Originally Posted by lynx
    The attempt to be "parsimonious" in that sense seems to be a fundamental error of approach, on both theoretical and evidentiary grounds.

    It is how science works though.
    By making fundamental errors in its applications of theory and interpretations of evidence?
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    Quote Originally Posted by forrest noble View Post
    Therefore man, at that time, could not have been the cause of the Smilodon's extinction by the competition of over-hunting large game. Instead the most likely cause of these extinctions in South America (thought to be the origin of the Smiladons) at the end of the last ice age was changing climates.
    With the utmost respect, Forrest, that is bullsh!t.

    For a start, we actually do not know when humans first came to North America. It was probably (but not certainly) some time between 12,000 and 16,000 years ago, but closer than that, we do not know. Within that time range, humans causing saber tooth extinction fits perfectly.

    Saber tooth cats survived 9 other climate change events of similar severity. Yet they died out only when humans arrived. Simple logic says ......
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