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Post by King Kodiak on Jun 30, 2020 17:58:50 GMT -5
Most likely weather related. That is the expert's main theory. The short faced bear was mostly carnivorous so when all the mega fauna died out at the end of the Pleistocene, the giant just could not adapt. The grizzly, as you just said, could hibernate and then eat his fish and plants. Then, at the start of the Holocene, when all was restored, the grizzly became very carnivorous.
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Post by brobear on Jun 30, 2020 18:11:52 GMT -5
It's like the bears of the genus Ursus have a few super powers. Their size changes according to environment and food availability. ( not individually of course, but the growing cubs ). The ability to hibernate. Their vast number of food choices on a bear's menu. In one location, the bears might be 80% vegetarian while those of another location might be 80% carnivorous. Some feeding mostly on fish and others consuming small rodents, insects and honey and still other hunting large prey animals and scavenging the kills of other predators. Some bears living in forests, some on grasslands, some at high altitudes on mountains, some in arctic tundra, and some even found in dry deserts. Everything I just listed can be seen in the brown bear. *Arctodus simus was huge and strong, but the grizzly was the better survivor.
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Post by King Kodiak on Jun 30, 2020 18:23:33 GMT -5
The Pleistocene epoch was an ice age, so in general, it was very cold. But within the ice age, there were colder periods and also hotter periods. So some researchers think All these drastic weather changes could had been one cause of the animals dying out. But then again some researchers dont, this is from your first post on page 1 of this thread:
"It was during the Pleistocene that the most recent episodes of global cooling, or ice ages, took place. Much of the world's temperate zones were alternately covered by glaciers during cool periods and uncovered during the warmer interglacial periods when the glaciers retreated. Did this cause the Pleistocene extinctions? It doesn't seem likely; the large mammals of the Pleistocene weathered several climate shifts."
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Post by brobear on Jul 1, 2020 3:30:21 GMT -5
advances.sciencemag.org/content/advances/2/6/e1501682.full.pdf Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation The mechanisms of Late Pleistocene megafauna extinctions remain fiercely contested, with human impact or climate change cited as principal drivers. We compared ancient DNA and radiocarbon data from 31 detailed time series of regional megafaunal extinctions and replacements over the past 56,000 years with standard and new combined records of Northern Hemisphere climate in the Late Pleistocene. Unexpectedly, rapid climate changes associated with interstadial warming events are strongly associated with the regional replacement or extinction of major genetic clades or species of megafauna. The presence of many cryptic biotic transitions before the Pleistocene/Holocene boundary revealed by ancient DNA confirms the importance of climate change in megafaunal population extinctions and suggests that metapopulation structures necessary to survive such repeated and rapid climatic shifts were susceptible to human impacts.
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Post by brobear on Jul 1, 2020 4:01:19 GMT -5
www.dandebat.dk/eng-klima5.htm The Kenozoic is the age of the mammals. The part of the Cenozoic, where man has existed is called Quaternary, which means the fourth (age). Quaternary is composed of the periods Pleistocene and Holocene. However, the Pleistocene lasted 2.6 million years, which is far, far more than the Holocene, which so far has only lasted about 11,000 years. Basically, the Holocene is just another inter-glacial, of which have already been many in the Pleistocene, but it is in this very special inter-glacial that human civilizations have evolved and all of the known history has taken place, and therefore we find this period in the geological and climatic history of the Earth immensely important. However, this article will deal with Pleistocene. Pleistocene is the period in Earth's history that we commonly refer to as the Ice Age. Through much of this period, the Earth's northern and southern regions were covered by kilometer thick glaciers. It is important to recognize that the Pleistocene was a series of real ice ages, separated by relatively short interglacial periods. The Pleistocene started 2.6 million years ago and lasted until the termination of the Weichsel glaciation about 11,711 years ago.
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Post by brobear on Jul 5, 2020 3:31:26 GMT -5
By Sully: Ross Barnett in his book "The Missing Lynx" supports the overkill hypothesis. He outlines that these same megafauna survived climate change previously in inter quaternary periods. And furthermore that the extinctions were selective (Miracinonyx and not acinonyx, stag moose and not moose) and ranged between multiple habitat niches, which cannot be explained by climate change. He also describes how the same species survived much longer in areas that humans had not inhabited (mammoths on Wrangel island for example). He asserts that there is no model which adequately explains worldwide extinctions of slow reproducing species. He contrasts this with multiple examples of humans arriving in an area correlating with megafaunal extinctions, this is true for Australia, Eurasia, North America and South America. He supplements this with the vast amount of evidence of human hunting in the fossil record, disproportionately so.
I used to subscribe to the idea that climate change weakened populations and humans pushed them over the edge, but Barnett makes a very compelling case that it is the fault of migrating humans and it's hard to disagree. The most compelling piece of evidence in my eyes being how different the Holocene is in this case to other periods of ice age warming, and there is one clear added variable which separates them.
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smedz
Ursus abstrusus
Recent Graduate
Posts: 410
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Post by smedz on Jul 5, 2020 8:00:13 GMT -5
Ah the Pleistocene, my favorite time period, things were just was cooler back then.
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Post by King Kodiak on Jul 12, 2020 9:59:58 GMT -5
LOOKS LIKE TWO CAVE LIONS RUNNING AWAY FROM A CAVE BEAR IN PLEISTOCENE EUROPE.
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smedz
Ursus abstrusus
Recent Graduate
Posts: 410
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Post by smedz on Jul 12, 2020 18:45:59 GMT -5
Actually those would be cave lions, and I think that's actually a cave bear.
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Post by King Kodiak on Jul 12, 2020 18:53:08 GMT -5
Actually those would be cave lions, and I think that's actually a cave bear. What makes you think that? So that would be Pleistocene Europe then? Those are cave spotted hyenas to the left? It looks like you might be right.
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smedz
Ursus abstrusus
Recent Graduate
Posts: 410
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Post by smedz on Jul 12, 2020 21:08:11 GMT -5
Actually those would be cave lions, and I think that's actually a cave bear. What makes you think that? So that would be Pleistocene Europe then? Those are cave spotted hyenas to the left? It looks like you might be right.Cave hyenas were not present in Beringia, which was the part of the mammoth steppe Arctodus lived in. So you are correct, this is Pleistocene Europe.
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Post by brobear on Jul 13, 2020 3:47:13 GMT -5
Actually those would be cave lions, and I think that's actually a cave bear. You are probably right. But I have always had the cave bear pictured as being more of a mountain dweller / forest dweller bear. In this, perhaps my entire perspective has been wrong.
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Post by brobear on Nov 1, 2020 0:07:54 GMT -5
From Wolverine at Wildfact: -The driving force for the core Asian steppe was an enormous and stable high-pressure system north of the Tibetan Plateau. -Deflection of the larger portion of the Gulf Stream southward, past southern Spain onto the coast of Africa, reduced temperatures (hence moisture and cloud cover) that the North Atlantic Current brings to Western Europe.
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Post by brobear on Nov 1, 2020 0:08:50 GMT -5
From Wolverine at Wildfact: North America
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Post by brobear on Nov 1, 2020 0:21:08 GMT -5
Some paleontologists suspect that the grizzly might have played a key roll in the extinction of the giant short-faced bears in North America. Arctodus simus first disappeared from Beringia after the arrival of the grizzly from Siberia. Soon after the grizzly began to populate North America in what is now the lower 48, the short-faced bears became extinct completely - with the lone exception of the little arboreal Andean bear of South America.
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Post by brobear on May 18, 2021 2:32:58 GMT -5
Bottom picture: Hippopotamus were in Europe but never in America. These saber-toothed cats are Homotherium.
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Post by King Kodiak on May 18, 2021 9:07:39 GMT -5
Bottom picture: Hippopotamus were in Europe but never in America. These saber-toothed cats are Homotherium. Yeah, the site messed up on that one, dont know why.
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Post by brobear on Oct 4, 2022 5:40:05 GMT -5
Perfectly Preserved Young Woolly Rhino Revealed By Melting Permafrost siamtoo.com/3799/ The incredible find was about three or four years old when it died at least 20,000 years ago. An absolute unit of a woolly rhino on display at the Weston Park Museum, Sheffield, UK. The new specimen discovered is a juvenile. Image credit: Chemical Engineer It is the best preserved juvenile woolly rhino ever found, with a lot of its internal organs – including its hazel-colored hair, intestines, lumps of fat and tissues – kept intact for thousands of years by permafrost. The Ice Age creature was discovered in the thawing permafrost in the Yakutia region in Russia’s extreme north in August. It is thought to be the best-preserved woolly rhino found there yet. “The young rhino was between three and four years old and lived separately from its mother when it died, most likely by drowning,” Dr Valery Plotnikov from the Academy of Sciences of the Republic of Sakha (Yakutia), who made the first description of the find, told the Siberian Times. “The [sex] of the animal is still unknown. We are waiting for the radiocarbon analyses to define when it lived; the most likely range of dates is between 20,000 and 50,000 years ago.” The perfectly preserved rhinoceros was discovered not far from another important recent find: Sasha, the only woolly rhinoceros in the world ever found, discovered in 2014. Sasha, has striking strawberry yellow plumage, dating back 34,000 years. According to Dr Plotnikov, the newly found specimen had “very thick short undercoat”. Sasha helped scientists demonstrate that woolly rhinos were covered in thick fur – something previously only cave paintings suggested. The new discovery adds to evidence that woolly rhinos are fully adapted to cold climates as children. Sasha the baby woolly rhino found in 2014 in Yakutia lived 34,000 years ago. Image credit: Albert Protopopov, The Siberian Times Currently, the Ice Age relic is still in Yakutia, as ice roads have to be formed before it can be transferred to the region’s capital, Yakutsk, to be studied by scientists.
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Post by brobear on Oct 4, 2022 5:41:52 GMT -5
Adult Woolly Rhino.
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