Upheavals in the Third Millenium BCE

[Minimalist]

In Guns, Germs and Steel the author argues that humans had to be the causal agent because these animals had survived numerous other climate fluctuations.

However, I tend to think as Digit does that humans merely provided the final straw to a species that was already under stress.

[Rokcet Scientist]

Yes, check Box E ... predators do not run a species to extinction due to feedback mechanisms unless they hunt for other reasons (such as the purposeful decimation of the buffalo in the west to starve Plains Tribes). However, climate, disease and other factors seem to have more to do with extinctions in ancient times. At best, humans might have been able to tip the balance just a little, nothing more.

Don't forget Box X ... tipping events! Like suddenly appearing erupting volcanoes in their path (http://www.snopes.com/photos/natural/maiken.asp), or disappearing land bridges, like the African Horn, Gibraltar, Bosporus, Bering Strait, North Sea, or exploding and splashing down astronomic debris. Or that certain gases reach a max. Like CO2 did/is doing. Green House Effect. Global warming, rising sea levels, disappearing habitable lands.

All of those would send HSS packin'!

There is any number of natural 'great impact factors' that could, and of course did, tip the course of events hundreds of times over the aeons.

Those people who met the Mammoth, and other large animals were hunter gatherers, like the native Americans. I know of no example where HG groups multiplied to the extent that they became too numerous for their environment.

Try Rapa Nui, or Guatemala/Yucatan! And I'm sure there are dozens more you guys could mention.

The native Americans didn't wipe out the Bison, and their counterparts in Europe didn't wipe out the Auroc, Moose, Elk, Musk Ox or Caribou.

But they certainly helped. And are currently thought to have been at least the tipping force.

Just for illustration: consider the paleolithic buildings in the Ukraine... constructed entirely from hundreds, sometimes thousands, of gigantic mammoth tusks! It must have required wholesale slaughter of mammoths, complete herds, and often, to gather those obscene numbers of tusks. Obviously it wasn't hard. Paleolithic HSS simply considered them readily available durable building material... and used them as such.

Or the northern hemisphere penguin! A high-calory foodsource that couldn't run away...
Their remaining cousins, such as they are, all master some modicum of flight capability. Literally. It's how they escaped HSS. Sofar.

So it did happen: HSS had a significant impact on the environment through all of (pre-)history.

Like GW, everything that goes wrong, somebody wants to blame HSS.
Three wet winters in a row would have decimated the Northern Proboscideans as they were adapted to dry cold conditions, THEN HSS may have finished them off!

Quite.

[Digit]

Rapa Nui is hardly a stereotype but rather an extreme example of what can go wrong.
If HSS had wiped out the large animals in NA they would have been faced with a number of alternatives.
1 Starvation!
2 Start farming.
3 Move onto other, smaller, prey animals.
The first alternative I refuse to even consider! Farming at that stage there is no evidence in support.
The third alternative would have been practical and is in fact what seems to have happened. But if the HSS population was so high as to not be sustainable by the herds of large prey the smaller ones would soon have followed suit.
This did not happen.

[Rokcet Scientist]

Maybe Mount St Helens exploded?
But good!
Like the hotspot under Yellowstone seems to be threatening to do. That would have unleashed 'nuclear winter' for a couple years to a decade. I'd bet that would cut down HSS numbers very drastically.
HSS would have had to almost start all over.

So it could be interesting to have a close look at timetables of volcanic eruptions over the paleolithic to see if they could be tied in with HSS migratory activity.

[Digit]

Any such activity as that Roc would have shown up in various ice cores as changes in the atmospheric gases and very distinctive aerosols, so I think we must discount that possibility.

[Rokcet Scientist]

Any such activity as that Roc would have shown up in various ice cores as changes in the atmospheric gases and very distinctive aerosols, so I think we must discount that possibility.

Are you saying such hasn't shown up? Afaik every single mile deep Greenland ice core sofar has revealed hundreds of such events over time!
Of which Tambora was the smallest.

[Forum Monk]

Strangely, you guys are looking at a period of the end of the younger dryas when the earth was actually warming up after a deep freeze. It also marks the time when Smilodon, Ground Sloth, Giants Beavers, and many megafauna go extinct as well as Homo Floresiensis.

I have eruptions somewhere, I will dig it up and post it shortly.

[Forum Monk]

Volcano!
http://www.volcano.si.edu/world/largeeruptions.cfm

[Rokcet Scientist]

Strangely, you guys are looking at a period of the end of the younger dryas when the earth was actually warming up after a deep freeze.

And flooded most of the habitable coastal plains, and cataclysmically breached land bridges like Gibraltar, or the African Horn, filling large erstwhile habitable basins fast.

It also marks the time when Smilodon, Ground Sloth, Giants Beavers, and many megafauna go extinct

Domino effect. Take out a key species and whole ecosystems collapse.

as well as Homo Floresiensis.

IF Homo Floresiensis were a separate species. But after the initial hype they are currently regarded an expression of insular dwarfism. Like African Pygmys, forest elephants, Wrangel Mammoths, etc.

[Minimalist]

I seem to recall reading that the Med flooded 5 million years ago. Too long for early man.

[Rokcet Scientist]

Volcano!
http://www.volcano.si.edu/world/largeeruptions.cfm

No pleistocene eruptions there.

[Rokcet Scientist]

I seem to recall reading that the Med flooded 5 million years ago. Too long for early man.

Maybe it dried up again in the meantime then (why not. 5 million years is a long time. Even in geological terms. A lot happens in 5 million years), because there are theories that the Pillars of Hercules collapsed around 9,500 BC. As a direct effect of the rising sea levels at the end of the Würm.
That, in turn, literally built up to the Bosporus breach, 3 millenia later.

[Digit]

No Roc, I'm not saying that. I'm saying that, as far as I know, no eruption of sufficient magnitude occurred during that time period.
If an eruption had occured that was sufficient to take out fauna on a world wide basis, why only the larger ones?
As the Wooly Mammoths were cold adapted, warming would have been there greatest threat. Ok, sufficient cold would have had the same result, but then other species would have suffered as well, this does not appear to have happened.
Logic therefore removes vulcanism as a cause.
Warming would have resulted in increased snowfall, which would have made foraging more difficult for large animal and with an increased chance of becoming soaked and bogging in softer ground.
Such large animals normally spend much of their time eating or moving in search of food, any increase in snowfall would have lowered their body temps as they ingested snow, time taken to reach forage and the increased time taken in uncovering it would have taken their toll on such large cold adapted fauna.
Melt water may well have trapped many animals into areas too small to sustain them.
The end result would be an increase in mortality rates and possibly a reduction in breeding success. Animals of that size are normally very slow to recover from large losses in their numbers.

[Rokcet Scientist]

No Roc, I'm not saying that. I'm saying that, as far as I know, no eruption of sufficient magnitude occurred during that time period.
If an eruption had occured that was sufficient to take out fauna on a world wide basis, why only the larger ones?
As the Wooly Mammoths were cold adapted, warming would have been there greatest threat. Ok, sufficient cold would have had the same result, but then other species would have suffered as well, this does not appear to have happened.
Logic therefore removes vulcanism as a cause.
Warming would have resulted in increased snowfall, which would have made foraging more difficult for large animal and with an increased chance of becoming soaked and bogging in softer ground.
Such large animals normally spend much of their time eating or moving in search of food, any increase in snowfall would have lowered their body temps as they ingested snow, time taken to reach forage and the increased time taken in uncovering it would have taken their toll on such large cold adapted fauna.
Melt water may well have trapped many animals into areas too small to sustain them.
The end result would be an increase in mortality rates and possibly a reduction in breeding success. Animals of that size are normally very slow to recover from large losses in their numbers.

And HSS tipped the balance by driving whole herds with fire over the edge. Literally: off rocky cliffs.
Thus their tusks ended up as building material for houses...

[Cognito]

Maybe it dried up again in the meantime then (why not. 5 million years is a long time. Even in geological terms. A lot happens in 5 million years), because there are theories that the Pillars of Hercules collapsed around 9,500 BC. As a direct effect of the rising sea levels at the end of the Würm. That, in turn, literally built up to the Bosporus breach, 3 millenia later.

Rok, the Straights of Gibralter looked similar in 9500bce to today, just the sea level was lower. The Mediterranean has been a sea for millions of years. The Bosporus sill elevates 185 feel above the present Mediterannean sea level and most likely breached first about 12,400bce due to glacial floods moving in the opposite direction of Ryan & Pittman's hypothesis. There appears to be a second breach around 9,600bce that scoured bedrock. Two deltas from those events are evident on the Mediterranean side of the Bosporus. Yes, the Mediterranean eventually topped over into the Black Sea about 5,650bce but the channel had already been cut.