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1 .(female professor) Last time on record that glaciers had spread out to cover large parts of the planet surface.
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2 .Okay, so this week, I\'m gonna talk about another prehistoric culture living at around the same time but on the other side of the globe.
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3 .These people live near the southern ice fields as far south as any people lived then, south of Australia in what we now know as the island of Tasmania.
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4 .During the LGM (Last Glacial Maximum), so much water was frozen in glaciers that the sea level was much lower than it is now.
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5 .So, Tasmania wasn\'t an island then, it was actually possible to walk from Australia to Tasmania on a land bridge. In fact, the archaeological record shows that prehistoric humans did exactly that.
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6 .This region, so far from the equator. And at this time, only 1,000 kilometers North of the Antarctic ice sheet was, as you\'d expect, very cold.
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7 .In the southwestern region of Tasmania, there are high, rocky mountains with many trees, both in the valleys and on the hilltops.
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8 .In fact, fossil evidence shows that many species of plants lived at these heights in prehistoric times. So, we know the climate surely as it was, was at least warm enough to sustain vegetation.
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9 .And archaeologists recently made a surprising discovery in these areas, despite the altitude, there were clear signs that humans had once made their homes here.
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10 .Sharp stone, cutting tools were found in many caves. Also, alves, needle-like pointed tools that were probably made from the bones of a wallaby, an animal similar to the kangaroo.
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11 .Blackened walls indicated the use of fires. Charred bone remains indicated that wallaby meat was a frequent part of the diet. For clothing, they would have sewn the wallaby hides with the bone alves.
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12 .Now, it\'s estimated that annual mean temperatures in Tasmania during the LGM were close to the lowest limit that humans can tolerate, especially in the southwestern mountains.
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13 .So why did early hunter gatherers choose to live at these higher elevations?
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14 .Well, traditionally, when archaeologists have looked at climate change, an ice age, for instance, they\'ve tended to make a basic assumption about how it might have affected human habitation patterns.
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15 .Namely, they\'ve assumed that any changes in such patterns resulting from the climate change must be related to food resources.
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16 .So, its prehistoric Tasmanians migrated up into colder, mountainous regions during the LGM.
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17 .The assumption would be that they, as hunter gatherers, will following their most likely sources of food. In this case, wallabies. And that makes some sense, right?
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18 .But these researchers, well, they took rather different and seemingly counterintuitive view of the situation.
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19 .They wanted to test the hypothesis that the prehistoric Tasmanians might have moved to higher grounds, not in spite of, but precisely because of the falling temperatures.
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20 .In other words, these higher elevations, despite having colder air temperatures than the lowlands, somehow offered people a chance to keep warm.
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21 .So how could that be? Well, remember that air temperature isn\'t the only factor affecting how cold it feels. You also have to take wind into account. And Tasmania at this time was a very windy place, indeed.
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22 .So, what might you find in the mountains that would help protect you from those biting winds? The researchers here proposed a couple of answers.
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23 .First there were the trees, which would both act as a natural barrier against the wind and provide firewood.
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24 .The low-lying coastal areas, during this time, by contrast, were largely treeless and covered by grasslands, but perhaps of even greater importance was the shelter offered by the caves I mentioned.
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25 .And interestingly enough, nearly all the caves where evidence of human habitation was found, had openings that faced away from the direction of the coldest prevailing winds.
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26 .These two factors then, trees and shelter, would’ve greatly contributed to the survival of the prehistoric Tasmanians.
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27 .So, to me, what the researchers are positing seems quite plausible that the Tasmanians’ choice of where to live was influenced at least as much by climate, as by considerations regarding the availability of food.
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