Humans: Destroyers of Mega Fauna

Discussion in 'Biology & Genetics' started by Saturnine Pariah, Jun 4, 2014.

  1. Arne Saknussemm trying to figure it all out Valued Senior Member

    Messages:
    1,353
    Perhaps it has to do with jungle density. While North American forests can be quite thick, I suppose they are not quite as dense as sub-Saharan jungles, or those of South and Southeast Asia or South America. Notice that no one so far has talked about the lack of big animals in the Amazon? Sure, there are no elephants or elk, but perhaps there either hasn't been for some time, or never was. (I don't know)

    I do know that new (to man) species as large as deer have recently been found in the Vietnamese jungle, and that in that just three or four human generations ago gorillas were thought to be mythical creatures. The Congo and many other tropical forests are just that vast.

    North America is vast, but consider the bounty of tropical nature. Besides more varieties of creatures, there is also a large number of them in a lush environment.

    Also there is megafauna and then there is megafauna. Are we talking about mammoths and saber-toothed cats and your La Brea Tar Pits type of animals, or are we just talking hippos and elephants? The mega fauna of the current era is quite shrimpy compared to what once was.

    Anyway, why listen to me? What do I know?

    Please Register or Log in to view the hidden image!



    I did just fine this interesting article that may help answer the OP:

    A 'smoking gun' on Ice Age megafauna extinctions

    What do you all think of that?
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. iceaura Valued Senior Member

    Messages:
    30,994
    There's no evidence of that, for the dozens of suddenly extinct megafauna.

    The usual hypothesis, and it matches the patterns we observe today, is that these megafauna co-evolved with human , or at least hominid, predation.

    The tool kit and behavioral repertoire available to the humans who first spread widely had been long in the devising (hundreds of thousands of years), and the threat from humans grew gradually enough that the animals had time to adapt - and have done so, visibly. African megafauna, for example, are notably hostile and far more difficult and dangerous to hunt than the same kinds of animals elsewhere. Megafauna everywhere flee and hide from the mere scent of humans, or attack them - but not where they have little experience with people, such as islands or continents only recently inhabited. Hermann Melville tells us that even within one generation formerly apathetic and easily approached whales had learned to school up for pod safety and flee distant ships - they didn't learn fast enough to prevent their extinction, though, which in several species was only staved off (if indeed it has been) at the last minute via human self-regulation and the sheer size of the oceans unable to support resident populations of hunters.

    Because it matches all the evidence we do have, nothing else does, and we've seen it happen several times recently enough to verify and study in detail (New Zealand, Hawaii, several Polynesian islands, Madagascar, etc).

    The Younger Dryas was too local, too small, has no similar examples, does not explain the other planetary human-correlated extinctions, and does not explain the pattern of extinctions (very large warmblooded vertebrates only). As a pressure on some of the extinct, sure, but every animal in North America had just survived an ice age.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Fraggle Rocker Staff Member

    Messages:
    24,690
    In the context of anthropology, the specific meaning of the term "civilization" is: the building of cities.

    The Agricultural Revolution, about 11,000BCE, was the first Paradigm Shift our species underwent: a wrenching change in the pattern of life, complicating the relationships among people and requiring new social institutions. The twin technologies of farming and animal husbandry (which together comprise agriculture) both permitted and required humans to give up their nomadic lifestyle and settle in permanent villages where they tended their crops and their flocks. The key advantage of agriculture was, arguably, the creation of a permanent food surplus. It was no longer necessary for neighboring tribes to fight for food during a drought.

    It soon became obvious that division of labor (each person practicing his best skill) and economies of scale (larger operations are more efficient and productive, at least up to a point) make large villages more prosperous than small ones. It became advantageous for neighboring tribes (now that they had no reason to be wary of each other) to merge into a single, larger village. This allowed and required a few people to become full-time specialists who improved the quality of life: roofers, potters, irrigation engineers, plant hybridization experts, animal tamers and midwives, shoemakers, musicians, tinkers, traders with other villages, etc. The down-side of this was that our ancestors were no longer spending their entire lives in the comfortable company of people they had trusted and cared for since birth. They had to learn to establish new relationships with people who were once strangers, or even enemies.

    The second Paradigm Shift, a mere thousand years later, was Civilization, the merging of the residents of multiple villages into cities. This was another wrenching change in the pattern of life--which is as good a definition as any of a "paradigm shift"

    Please Register or Log in to view the hidden image!

    . People had to develop the trust, attitudes and social skills to live in harmony and cooperation with strangers. Furthermore, the old-fashioned method of maintaining harmony and order, "do what Grandfather says," no longer worked. Formal governments had to be established: a hierarchy of command and trust. It also required the building of new structures such as granaries and the establishment of new occupations such as resolving disputes between strangers, and carrying food from the outlying farms into the city--with no wheels or draft animals, using only the travois to augment human labor.

    So when we talk about civilization in this context, we refer to cities populated by people who are not well acquainted and therefore require a formally administered organization, and which encourage a greater division of labor which leads to the creation of many new occupations.

    The first cities were built of wood and stone, using tools of wood and stone.

    The next Paradigm Shift was the discovery of the technology of metallurgy around 3000BCE, ushering in the Bronze Age. This is a topic for another discussion.

    The Western Hemisphere was cursed by the same accident of geography that plagued Africa: a north-south orientation. This makes it difficult for societies to trade knowledge of crops and flocks, which often cannot thrive in a different climate. Because of this, it took much longer for villages to merge and grow into cities. Olmec civilization was founded more than 8,000 years later than in Mesopotamia, Inca civilization arose more than a millennium later, and as I noted earlier, the North Americans had barely begun the process of city-building when the Christians arrived with their guns.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Arne Saknussemm trying to figure it all out Valued Senior Member

    Messages:
    1,353
    Well Friend Fraggle, I'm not disagreeing with you. Those paradigm shifts were significant points in the history of civilization. However, let's consider the three 'revolutions'. They were the agricultural, industrial and, well, 'informational' would be a rather wonky sort of word to introduce - I mean the advent of the Age of Information. Not too many years ago, I took pride in my ability to use the library card catalog as others could play a piano. I thought myself a virtuoso, but of what use is my skill now with laptops and search engines? The plow, the steam engine and the CPU, if you will are the tools of these three ages. Although the Industrial revolution began in Germany, Britain and America but the same time (early 19th century) in some parts of the developing world and perhaps for some individuals there who were born in villages, they may have witnessed the two latter revolutions in their life times. I've known Javanese people in the 1990's when I was in Indonesia who were amazed that my living room floor was ceramic tiles rather than packed and swept earth. Now they have iPads!
     
  8. sculptor Valued Senior Member

    Messages:
    8,466
    long ago
    I read an article about the findings in the stomach of a mammoth unearthed in siberia. The stomach was said to contain flowering plants which were now growing much farther south in Georgian S.S.R.

    ................
    So many "smoking guns".............
    one wonders
    During ww2, a study was carried out after a small battle, wherein autopsies were performed and ballistics studied. The upshot was that only one in 10 soldiers had actually shot all of the enemy combatants. = 10 smoking guns, only one of which fulfilled it's desired function.
    .............

    as/re:
    Perhaps, this is where the genius and abilities of sapiens sapiens could/would/will(?) come into play.
     
  9. iceaura Valued Senior Member

    Messages:
    30,994
    The largest known pyramid in the world, by volume, was built next to an engineered diversion of a tributary river of the Mississippi River - the entire river diverted and rechanneled for convenience of irrigation - just outside of Saint Louis, Missouri. It still exists, and has been partially studied: The flat (truncated) top was large enough for several buildings and fair sized open areas (religious gatherings maybe, large gardens possibly, playing fields for a game resembling lacrosse, nobody knows). Apparently the city dwellers responsible, or similar people, had similar population centers up and down the Mississippi River from the mouth into present day Iowa.

    They vanished before the Christians arrived with guns in that part of the world. The very earliest white explorers to the northern 3/4 of the Mississippi/Missouri watershed found large areas of uninhabited forest and odd prairie openings well populated with game, smaller and scattered tribes and groups of people with only intermittent trade or other contact, and signs that people were spreading or being pushed west from unstable and increasing populations to the east. (The encounters with prosperous and expanding Plains horse-adapted cultures were yet to come).

    The Mississippi/Missouri watershed with its population centers would have been the main trade route and communication route of the entire continent, of course - the only easy route of travel and trade in this continent with its N-S mountain ranges walling off both oceans, and thus the presumed artery for disease proliferation from the first European contacts.

    Mammoths are no longer found where such plants grow - despite the fact that mammoths probably could walk routinely as fast and as far as elephants do today, almost certainly migrated routinely as every large herbivore of the far north does today, and could therefore change their home ranges much faster than most plants can migrate.

    That daytime summer temperatures all across high latitudes of the northern hemisphere were higher a few thousand years ago than they are now is well known - badgers dug holes near Hudson Bay in what is now permafrost, for example (although an alternative explanation has been proposed - that permafrost was more rare in the days when elephants and other huge animals were breaking up and fertilizing the soil). The winter nights, on the other hand, seem to have been about as cold - the 40 below line that separates the arctic trees from the southern ones did not move nearly as far as the range of the badger.

    And not just species but entire genera, more than a dozen of them, disappeared from North America in one 1500 year interval: 11,500 - 10,000 bp. That's the entire continent, both sides of all mountain ranges, etc. - not merely the regions severely pressed by the Younger Dryas cooling.

    btw: perhaps the best comparable extinction event to the North American one would be the South American one, in a window about 10,000 years ago - about 400 years after the NA one. There was no overpowering glaciation there, and no climate event resembling the Younger Dryas, but the same extinction pattern - big vertebrates largely wiped out in a couple of thousand years at most, coincident with the arrival of humans who left evidence of sophisticated projectile weapons and landscape scale use of fire.
     
  10. NCDane Registered Senior Member

    Messages:
    155
    Few surviving Afro-Asiatic megafauna are restricted to heavily forested environments.
    The only extinct American species that might have been was the leaf-eating Giant Sloth.



    For the purpose of this discussion I would limit the term to species weighing over 75 kilo maximum, figure chosen so as to include the Dire Wolf.



    Thank you for the interesting link, which endorses climate-induced loss of one important menu item as the source of several megafauna species extinction. However, the Americas were until ~10,000ya inhabited by at least five probiscid species, some ranging into the tropics and despite the linked article it is not clinched that any of them were overdependent one item from the cold steppe menu.
     
  11. GeoffP Caput gerat lupinum Valued Senior Member

    Messages:
    22,087
    With primitive gear, extinction probably takes a lot longer. There's no way the passenger pigeon could have been extirpated without modern equipment (for the period).
     
  12. Arne Saknussemm trying to figure it all out Valued Senior Member

    Messages:
    1,353
    Your welcome, NCDane. I suppose the article I linked you too was just another theory after all.

    I don't mean to muddy this discussion even more than it's been muddied by me and some others, but perhaps it is also worth noting something Pi in The Life of Pi remarked upon. According to his father, who was a zookeeper, it is possible and their have been instances wherein large carnivores lived in modern urban centers for years - undetected.

    As "Pi' is only a work of fiction, I am not sure if this is really true, but Pi's dad said that escaped, formerly captive, lions and bears and the like have lived in modern-day American cities preying upon dogs, cats, rats, chickens and other animals in open pens at slaughterhouses. These large predators aren't stupid and understood that they must avoid humans. So they only ever hunt in the darkest, deepest night upon a limited range and sleep in abandoned buildings in blighted areas during the day.

    If I recall correctly, once Pi had safely washed ashore on the Mexican coast and was recuperating from his unfortunate voyage in a life boat with an underfed Bengal tiger, he was wondering how Richard Parker (the tiger) was faring. When Pi had last seen the enormous predator he had been loping off into the Mexican jungle. Pi assumed Richard Parker was doing quite well for himself there. Sure, he'd be lonely with no tigresses about, but he would survive.

    What do you think?
     
  13. NCDane Registered Senior Member

    Messages:
    155
    iceaura: Please consider formatting your posts to include the username of the person whose reply you are quoting and addressing.



    Does the commentary above refer to the Americas? Thousands of years would be needed to allow for an initially tiny stone-age population to denude both North and South America of so much megafauna. And in fact the possible date for first human inhabitation of the Americas has been moved back to as far as ~25,000ya, see link:

    http://www.smithsonianmag.com/scien...-come-to-the-americas-4209273/?no-ist=&page=3

    Of course the longer the residency the greater the opportunity for humans to commit the ecological genocide they are accused of.

    Also consider the same American megafauna included numerous Eurasian relatives which also died out before historical times. More on them shortly.



    I would like to know much more about the “patterns we observe today”. In process in the 21st century? Can you elaborate, or provide a citation link?



    But the Eurasian megafauna cousins of the Americans were not similarly deprived of evolutionary contact with hominids, yet also failed to survive.

    And as you note below in the case of whales it need not take more than one traumatic human encounter to imbue a herd of animals with aversion. This generality ought surely apply to the presumably highly intelligent American elephants, and might to any social animals. If so, long-term evolutionary development would be redundant.

    Also, you are saying that African lions and leopards must be more hostile and difficult to hunt than Asian lions and leopards, and tigers. However, all these African and Asian megafauna cat species survived into historical times in ranges of millions of square miles, so if disparate levels of aggression actually exist they made no difference in survival outcome until ~6000ya at earliest.



    A hungry American predator would on first encounter surely have wasted little time attacking a group of obviously weak and slow humans, and it is questionable that a herd of American elephants would have tolerated close enough approach by enough humans to get off enough spear throws to kill and then escape.



    If whales could develop an immediate aversion to humans then elephants probably could too, and several other species might also, despite lower intelligence.



    The insular fauna mentioned above were too grossly defenseless compared to American megafauna to make a useful comparison. Even the largest insular specimens would have been unable to put up the resistance of the smallest extinct American carnivore, the 75kg dire wolf, and they would have been dwarfed in size, in tooth and in claw by the largest, the short-faced bear, which could attain 1000kg in weight and 14 feet in vertical reach. Then there are the huge vegetarian elephants.

    It occurs to me to wonder why early Americans would bother hunting megafauna, except for sport, when there must have been so much less dangerous large game available. Such game- bison and at least five species of deer in North America- helped support a large megafauna predator population, and so should have been an easy enough mark for humans with their superior hunting skills. Perhaps some or all of the disappearancing megafauna predators were those least able to compete for what game was left over after humans had had their fill.



    YD by itself might be an unlikely explanation, but overall climate conditions should remain on the table of items to be investigated.
     
    Last edited: Jun 11, 2014
  14. NCDane Registered Senior Member

    Messages:
    155
    This strikes me as a bit far fetched. However:

    You should be interested to know that four bears have visited my home city of Greensboro NC (pop. now 277000) since I have lived here (1971-present). The first three were tranquilized and removed to the wild. One of these came to tranquilized rest in a backyard marijuana garden, with unpleasant legal consequences for the unlucky gardener. Someone made a bit of money selling T-shirts with a picture of a bear, awake and happy, surrounded by contraband vegetation.

    The most recent bear visit, just 2-3 years ago, was by a male ~75kg and unfortunately the idiot wildlife people had decided on a new bear policy, and let him wander around, expecting him to leave town on his own without damaging anything. After several days the poor beast ventured onto the airport runway and had to be killed. I hope the idiot wildlife people have regained their senses, because the bear population is growing in this state, and we are sure to have more visits.

    You should also be interested in the outcome of this suburban NJ bear encounter:

    http://news.nationalgeographic.com/news/2006/06/060613-cat-bear.html

    (from link);
     
    Last edited: Jun 11, 2014
  15. Arne Saknussemm trying to figure it all out Valued Senior Member

    Messages:
    1,353
  16. NCDane Registered Senior Member

    Messages:
    155
  17. Arne Saknussemm trying to figure it all out Valued Senior Member

    Messages:
    1,353
    Probably terribly remote jungle locations, and I guess all there is to see is ramparts. Good luck to the looters!
     
  18. sculptor Valued Senior Member

    Messages:
    8,466

    Please Register or Log in to view the hidden image!



    This is an image of 2900 terra preta sites(as mentioned above)
    The lowland sites were built up and connected by raised causeways. The upland sites had large water reservoirs dug uphill from the terra preta garden spots.

    back of the envelope
    each site may have held 50-200 people
    x 2900 = up to 580,000 people---and that is only for the area and time-----

    as mentioned earlier, they seem to have reached their peak long before the europeans arrived
    ...............
    as re looters, if these are the sites mentioned in the above linked, then there really isn't a lot for thieves to cart off.
    ................
    these people created rich organic soils that are still rich well over a thousand years after their creation.
     
  19. iceaura Valued Senior Member

    Messages:
    30,994
    The usual cutoff in these discussions of North American extinction is 40-45 pounds, or about 20 kilos.
    Why? Figure a doubling time of 20 years under such disease free, well fed, and prosperous circumstances, and a thousand turns into a million in less than 2000 years. By that time they've covered the continent, killing a quarter of a million large herbivores a year for centuries, and there isn't a hill of meat to be found outside of the bison - who, like the whales of modern times, have taken to traveling fast and in large herds only.
    We don't know the techniques (the San use leghold drags for elephants, others use pit traps and deadfalls etc) but there's little question that large herbivorous animals need to be taught to be at all wary of people - in places where moose are not hunted, for example, they allow people to get quite close (on Isle Royale the mothers birth near the ports and buildings as cover from wolves, and visitors have to be warned not to approach them too closely - spear range is routine). It might have taken quite a while for the observing elephants to connect the new animals with the troubles of their herdmates, also - it's not as easy at it seems for even an intelligent animal to figure out something as new as that.
    The Kalahari bushmen's term for elephant is "hill of meat". An unwary and easily found hill of meat is not particularly dangerous, anyway - and much easier to bring down than twenty small and flighty and sparse deer hiding in the bushes.

    Not at all. The Asian species had almost as much time to adapt to the emerging lethality of humans as the African.
    Too little, too late, time after time that we know of. The problem is the low reproductive rate and smaller initial populations of the very large.
    No large mammalian predator is that careless - strange animals are always approached with caution, and ones carrying fire presumably even more so. This is a world of porcupines, skunks, Gila monsters, toads, scorpions, etc. And of course such caution would have been more than justified - even modern well-adapted predators take their lives in their hands when attacking people.
    The cheetahs were smaller, if that matters.

    But you underestimate human predatory capability, as well as the defensive capabilities of thousand pound moas etc. Even modern Cassowaries, much smaller birds, are quite dangerous - but nevertheless vulnerable to human hunters.
     

Share This Page