Showing posts with label megafauna. Show all posts
Showing posts with label megafauna. Show all posts

Humans Did Not Kill Off Megafauna

During the Middle-Late Pleistocene, one million to 10,000 years ago, more than 50 species of animal disappeared, the last to do so 46.4 thousand years from the present. The reason for the demise of the giant creatures is hotly debated. Some scientists claim that the spread of Man across the globe was the cause. This is suspect, however, because there were so few of them. Killing the odd animal would not have made a significant impact.

Many believe that the end date for megafauna is incorrect. As stated above, the theory that humans killed them off by definition means that people and animals lived side-by-side for a considerable time. Evidence in Australia certainly points to this - 13 species of large animals were here on human arrival. Moreover, the people mainly relied on subsistence strategies for food. Their weapons were not very efficient. A boomerang is highly inaccurate and the range of a spear is limited.

Megafauna died out over a long period of time, not all at a specific date. Species lingered on in many regions. Just assuming that humans killed them is a mistake and diverts from the discovery of why the large animals became extinct. This was a time of extremes in climate. Perhaps a series of wild swings in climate gradually reduced their number to the tipping point where reproduction did not take place.
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Society
TwitThis

Aboriginals Did Not Wipe Out Megafauna

The argument continues over whether humans were responsible for the extinction of megafauna. Giant emus, large kangaroos, marsupial lions and diprodons were destroyed by Aboriginals in Australia according to new research. This claim is based on fungi in dung of herbivores. For 130,00 years, despite dry periods, charcoal and pollen levels in dung remained the same until Aboriginals arrived. This means that climate change was not responsible for the extinction of megafauna 40,000 years ago.

There is a problem with this. When Captain Cook arrived in Australia the Aboriginal population was extremely low. Forty thousand years ago there would have been only a few hundred thousand of them. How could this low number possibly destroy all of the large animals? Some megafauna would have survived in regions where Aboriginals did not go. Australia is a very large continent.

It is claimed that when the megafauna died out the vegetation changed with more fires, and eucalyptus forests spread out killing off rainforests. Spores in dung is flimsy evidence to support a claim that human arrival led to the demise of megafauna. Rainforests being taken over by eucalyptus sounds very much like climate change. Furthermore. prevailing evidence shows no human remains among megafauna fossils.

Saying that the dung research proves humans destroyed giant animals is still not proven beyond doubt. Gavin Prideaux's announcement that the study "supported mounting evidence that climate change was not to blame" is premature.
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Paleontology

Humans Wiped Out Australia's Megafauna

Humans destroy more things in the environment than climate change. This is especially the case in Australia where over the last 50,000 years people have wiped out the county's megafauna. Before Aboriginals arrived flightless birds, large reptiles and giant marsupials lived a carefree existence.

Humans slaughtered the large animals in a very short period of time. More accurate dating of bones shows that megafauna died out abruptly. When the giant creatures were in large numbers there is no evidence of human tools. After the Diprotodon, Australia's largest marsupial, large kangaroos and flightless birds died out stone tools appeared. Accurate dating shows they did not exist at the same time even though they were found together at certain locations. When humans became settled the large animals were gone. The odd thing is that humans and megafauna must have coexisted for at least 5,000 years. But this is a very narrow window to find evidence of both living side by side.

This gives weight to the theory that the arrival of modern Man in the Americas caused the demise of the mammoth. Though there is a problem with the American story. Megafauna "ruled" during the ice age which occurred 12,000 years ago. Its seems that when the ice ages ended life changed for the large animals. The climate was then well and truly against the survival of mammoths, short-faced bears, giant bison and sabor-toothed tigers. Some megafauna, however, continued to survive in Kansas, and Nebraska after the ice age period. The skeleton of a giant beaver has been found dating from 10,000 years ago. So Man could still be the culprit.
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