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Post by brobear on Sept 1, 2020 16:11:33 GMT -5
In Europe, there were saber-toothed cats and cave lions. But the herbivorous cave bears were no competition to the brown bears over meat.
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Post by OldGreenGrolar on Sept 1, 2020 21:20:27 GMT -5
In Europe, there were saber-toothed cats and cave lions. But the herbivorous cave bears were no competition to the brown bears over meat. So basically the brown bear and cave bear can live together without fighting and in harmony except during mating season.
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Post by King Kodiak on Sept 2, 2020 10:26:32 GMT -5
In Europe, there were saber-toothed cats and cave lions. But the herbivorous cave bears were no competition to the brown bears over meat. So basically the brown bear and cave bear can live together without fighting and in harmony except during mating season. Yeah. I read somewhere that the brown bears also slept inside the caves, but just a little inside, not deep inside like the cave bears.
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Post by brobear on Oct 29, 2020 4:17:41 GMT -5
Searching for information on the Pleistocene American brown bear is not an easy task. It is rare to find a diorama of Pleistocene N. America which includes the grizzly. Even less common, a book on Pleistocene N. American wildlife which includes the grizzly.
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Post by brobear on May 20, 2021 3:57:20 GMT -5
iceage.museum.state.il.us/mammals/grizzly-bear-0 Status at the end of the Pleistocene: Not only did the grizzly bear survive the mass extinctions of the terminal Pleistocene, but they were able to expand into most of North America as the continental ice sheets retreated to the north. By the early Holocene, they ranged as far east as Ontario, Ohio and Kentucky and as far south as Mexico. This distribution retreated north and west, somewhat, as environmental conditions continued to fluctuate through the Holocene, and by historic times, they ranged through most of western North America and into the central Plains of the U.S. (Schwartz et al. 2003). Midwestern Paleontological Finds: Despite their relatively recent arrival, remains of grizzly bears have been recovered from late Pleistocene sites in the central Midwest. Most notably, remains have been recorded at Polecat Creek in eastern central Illinois, the Overpeck Ursus find south of Dayton, Ohio, and in Welsh Cave, southwest of Lexington, Kentucky.
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Post by brobear on May 20, 2021 7:06:17 GMT -5
Most of our "elite" posters, those who are intelligent, knowledgeable and educated enough to be highly respected by other "elite" posters, estimate that the Pleistocene inland grizzly averaged about 700 pounds. This would place them at roughly the size of Ussuri and Hokkaido brown bears.
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Post by OldGreenGrolar on Jun 9, 2021 7:30:48 GMT -5
The grizzly who lived among saber-toothed cats, dire wolves, and giant bears. Grizzly bears are actually very adaptable when it comes to living among many competitors. I doubt introducing new animals in their territory will drive them extinct not shipping them to places where a lot of land predators live.
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Post by OldGreenGrolar on Jun 9, 2021 7:31:26 GMT -5
Most of our "elite" posters, those who are intelligent, knowledgeable and educated enough to be highly respected by other "elite" posters, estimate that the Pleistocene inland grizzly averaged about 700 pounds. This would place them at roughly the size of Ussuri and Hokkaido brown bears. Pleistocene animals in general seem to be heavier than their modern counterparts.
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Post by brobear on Jun 9, 2021 7:49:11 GMT -5
Most of our "elite" posters, those who are intelligent, knowledgeable and educated enough to be highly respected by other "elite" posters, estimate that the Pleistocene inland grizzly averaged about 700 pounds. This would place them at roughly the size of Ussuri and Hokkaido brown bears. Pleistocene animals in general seem to be heavier than their modern counterparts. Actually, once the heavy-duty predator/scavenger competition became extinct, leaving the grizzly at the top of the food chain, these American brown bears grew larger. For thousands of years, where available, the grizzlies fed heavily on bison - scavenged from wolf kills, scavenged from bison dying of natural causes, and hunting bison calves and cows. I seriously doubt that these big grizzlies ever purposely chose a big bull bison as prey, but there were probably cases of a bull bison instigating a fight in defense of the herd. In later years, these bison were joined by feral cattle and mustangs. There were very big grizzlies living in the Great Plains up until the invention of the modern rifle, beginning in 1848.
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Post by OldGreenGrolar on Jun 9, 2021 7:55:08 GMT -5
If it was not for all these poaching, the grizzlies would be much heavier today.
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Post by brobear on Jun 9, 2021 8:03:46 GMT -5
If it was not for all these poaching, the grizzlies would be much heavier today. Today, according to my understanding, we have three varieties of grizzly. ( 1 ) the huge coastal salmon-eaters. ( 2 ) the barren ground tundra grizzlies. ( 3 ) the Rocky Mountain grizzlies. These bears really haven't changed much ( if any ) in size since the days of the "Old West". The big grizzlies were those living out on the open prairie and the California grizzly - now extinct. *Edit and add: W.P. Hubbard, the leading bear expert of his time, researched the size and weights of those grizzlies of the 19th century American prairie. He specifically stated that his estimate for the weight of the average full-grown male grizzly in that location of 850 pounds was no exaggeration. He went according to bears actually weighed.
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Post by brobear on Jul 24, 2021 4:56:37 GMT -5
The greatest mystery to me, and I've touched on this topic before, is just how did the grizzly she-bear manage to survive and raise cubs in such a hostile environment. She had to deal not only with the grey wolf, but also dholes and the much larger canine called the dire wolf. There were also a variety of big cats including the giant jaguar, the scimitar cat, the saber-toothed cat, and the American lion. Last but not least, there were not only big male grizzlies to watch out for, but also the giant short-faced bears. The common belief is, the grizzly developed a highly aggressive nature from life in such a rough "neighbourhood". It is thought that grizzlies were more aggressive before their introduction to the modern breech-load rifle ( invented in 1848 ). Although, they were never the "monsters" that some pioneers spoke of. But, some thousands of years of Mama grizzly raising her cubs in such a hostile environment might explain why she is often considered to be the most dangerous bear on Earth today.
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Post by tom on Jul 25, 2021 6:44:53 GMT -5
That is a very good hypothesis. She would had to have been ultra aggressive as well as having a very acute sense of awareness of her surroundings. Be able to lead her cubs away long before the other predators were in sight.
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Post by brobear on Aug 29, 2021 5:35:10 GMT -5
www.pnas.org/content/97/4/1651 Population genetics of Ice Age brown bears. Abstract The Pleistocene was a dynamic period for Holarctic mammal species, complicated by episodes of glaciation, local extinctions, and intercontinental migration. The genetic consequences of these events are difficult to resolve from the study of present-day populations. To provide a direct view of population genetics in the late Pleistocene, we measured mitochondrial DNA sequence variation in seven permafrost-preserved brown bear (Ursus arctos) specimens, dated from 14,000 to 42,000 years ago. Approximately 36,000 years ago, the Beringian brown bear population had a higher genetic diversity than any extant North American population, but by 15,000 years ago genetic diversity appears similar to the modern day. The older, genetically diverse, Beringian population contained sequences from three clades now restricted to local regions within North America, indicating that current phylogeographic patterns may provide misleading data for evolutionary studies and conservation management. The late Pleistocene phylogeographic data also indicate possible colonization routes to areas south of the Cordilleran ice sheet.
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Post by brobear on Jan 4, 2022 23:34:21 GMT -5
Solving the disappearance of bears and lions with ancient DNA www.sciencedaily.com/releases/2022/01/220104102633.htm An international team of researchers led by the University of Adelaide, suggest a change in climate is the likely cause of the mysterious disappearance of ancient lions and bears from parts of North America for a thousand years or more prior to the last Ice Age. In a study in Molecular Ecology, the researchers sequenced DNA from fossils of cave lions and bears from North America and Eurasia to better understand the timing and drivers of their past movement between continents. Co-author, Dr Kieren Mitchell from the University of Adelaide's Australian Centre for Ancient DNA said, "There's a common perception that outside of mass extinctions or direct human interference, ecosystems tend to remain stable over thousands or even millions of years. "As illustrated by our study of the fossil record, that's not necessarily the case. "Previous research has shown that brown bears (or grizzly bears) disappeared from some parts of North America for thousands of years prior to the last Ice Age. They later reappeared, walking from Russia to Alaska across the Bering Land Bridge -- possibly at the same time as people moved across the Bridge into North America too. "But no-one knows exactly why they disappeared in the first place, which is why studying this event is important." A key finding of the new research is that cave lions from the same area became extinct more than once -- before their final extinction they also disappeared and reappeared thousands of years later, around the same time as bears. There is no evidence that people caused these temporary disappearances, and cold Ice Age conditions were not to blame. "Instead, it looks like a smoking gun pointing to some kind of change in their ecosystem," Dr Mitchell said. The timing of lions and bear extinction from parts of North America (specifically Alaska and the Yukon Territory) coincides with evidence of widespread vegetation change in the region. The researchers suggest that warm temperatures before the last Ice Age may have caused a change in the abundance of different kinds of plants, which had knock-on effects on herbivores and then their predators (like bears and lions). Colder temperatures leading up to the last Ice Age might have reversed this change and made the area more hospitable for herbivores, and in turn their predators. "Overall, these findings demonstrate just how changeable past ecosystems have been, and also how the abundance of different species can be very sensitive to changes in climate," Dr Mitchell said. Lead author from the University of Adelaide Dr Alexander Salis said: "The shared patterns of dispersal between lions and bears correspond with the presence of the Bering Land Bridge that connected Russia and Alaska during Ice Ages. "The Bridge was periodically exposed and inundated by changing sea levels during the last few Ice Ages, allowing intermittent dispersal of animals and people between continents and changing the faunal composition. "While many might think that species arrive in a region and stay put, we show that the past was much more dynamic, involving multiple waves of dispersal and local extinctions in this case."
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Post by brobear on Apr 15, 2022 1:45:05 GMT -5
Ancient Fossil Offers New Clues To Brown Bears Past www.sciencedaily.com/releases/2004/11/041115002514.htm Date: November 15, 2004 Source: University Of Alaska Fairbanks Summary: While nosing around the Quaternary mammal collection at the Provincial Museum of Alberta two years ago, Paul Matheus, a paleontologist with the Alaska Quaternary Center, came across a brown bear fossil that seemed out of place. The fossil had been collected by Jim Burns, curator of Quaternary mammals at the PMA a few years earlier near Edmonton, Alberta, in gravels that date to before the last ice age (older than 24,000 years). If this was true, Matheus thought, it could be a very important find.
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Post by brobear on May 27, 2022 9:45:29 GMT -5
JANUARY 4, 2022 Solving the disappearance of bears and lions with ancient DNA phys.org/news/2022-01-lions-ancient-dna.html An international team of researchers led by the University of Adelaide, suggest a change in climate is the likely cause of the mysterious disappearance of ancient lions and bears from parts of North America for a thousand years or more prior to the last Ice Age. In a study in Molecular Ecology, the researchers sequenced DNA from fossils of cave lions and bears from North America and Eurasia to better understand the timing and drivers of their past movement between continents. Co-author, Dr. Kieren Mitchell from the University of Adelaide's Australian Centre for Ancient DNA said, "There's a common perception that outside of mass extinctions or direct human interference, ecosystems tend to remain stable over thousands or even millions of years." "As illustrated by our study of the fossil record, that's not necessarily the case." "Previous research has shown that brown bears (or grizzly bears) disappeared from some parts of North America for thousands of years prior to the last Ice Age. They later reappeared, walking from Russia to Alaska across the Bering Land Bridge—possibly at the same time as people moved across the Bridge into North America too." "But no-one knows exactly why they disappeared in the first place, which is why studying this event is important." A key finding of the new research is that cave lions from the same area became extinct more than once—before their final extinction they also disappeared and reappeared thousands of years later, around the same time as bears. There is no evidence that people caused these temporary disappearances, and cold Ice Age conditions were not to blame. "Instead, it looks like a smoking gun pointing to some kind of change in their ecosystem," Dr. Mitchell said. The timing of lions and bear extinction from parts of North America (specifically Alaska and the Yukon Territory) coincides with evidence of widespread vegetation change in the region. The researchers suggest that warm temperatures before the last Ice Age may have caused a change in the abundance of different kinds of plants, which had knock-on effects on herbivores and then their predators (like bears and lions). Colder temperatures leading up to the last Ice Age might have reversed this change and made the area more hospitable for herbivores, and in turn their predators. "Overall, these findings demonstrate just how changeable past ecosystems have been, and also how the abundance of different species can be very sensitive to changes in climate," Dr. Mitchell said. Lead author from the University of Adelaide Dr. Alexander Salis said that "the shared patterns of dispersal between lions and bears correspond with the presence of the Bering Land Bridge that connected Russia and Alaska during Ice Ages." "The Bridge was periodically exposed and inundated by changing sea levels during the last few Ice Ages, allowing intermittent dispersal of animals and people between continents and changing the faunal composition." "While many might think that species arrive in a region and stay put, we show that the past was much more dynamic, involving multiple waves of dispersal and local extinctions in this case."
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Post by brobear on Jun 20, 2022 4:47:08 GMT -5
Population genetics of ice age brown bears. www.semanticscholar.org/paper/Population-genetics-of-ice-age-brown-bears.-Leonard-Wayne/495ddee752721073e4ad5364e9da573088e4ecfa The Pleistocene was a dynamic period for Holarctic mammal species, complicated by episodes of glaciation, local extinctions, and intercontinental migration. The genetic consequences of these events are difficult to resolve from the study of present-day populations. To provide a direct view of population genetics in the late Pleistocene, we measured mitochondrial DNA sequence variation in seven permafrost-preserved brown bear (Ursus arctos) specimens, dated from 14,000 to 42,000 years ago. Approximately 36,000 years ago, the Beringian brown bear population had a higher genetic diversity than any extant North American population, but by 15,000 years ago genetic diversity appears similar to the modern day. The older, genetically diverse, Beringian population contained sequences from three clades now restricted to local regions within North America, indicating that current phylogeographic patterns may provide misleading data for evolutionary studies and conservation management. The late Pleistocene phylogeographic data also indicate possible colonization routes to areas south of the Cordilleran ice sheet.
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Post by brobear on Jul 2, 2022 9:24:39 GMT -5
Early prehistory: 70,000-10,000 years ago www.allgrizzly.org/early-prehistory This section of History covers the early prehistory of grizzly bears in North America, from roughly 70,000 to 10,000 years before the present. More specifically, the focus of this section is on changes in distributions of grizzly bears and the environments in which they lived during the late Pleistocene (the last Ice Age) and early Holocene (our contemporary Age). I don't address ancestral diets, as such, which I cover in another section devoted to the topic (see Ancestral diet). Even so, I present a lot of material here, probably because I am so interested in this critical transitional period between the harsh and cold conditions of the Ice Age to the, in many ways, more benevolent conditions of our current warm epoch. Yet many species of large mammals went extinct during this transition. The causes are debated, but there is no doubt about how much and how rapidly the world changed, and the extent to which these changes would have challenged all of the existing species to adapt in whatever ways they could. Clearly, many did not succeed and, of those, most were the largest-bodied of all (the megaherbivores and megacarnivores). But grizzlies seemed to flourish, probably because many of their competitors and predators disappeared. On the other hand, grizzlies increasingly shared this world with another extremely successful and rapidly expanding omnivore--humans. I cover early relations in North America between the two omnivores--grizzlies and humans--in a separate section because of the multi-faceted and complex nature of the topic (see The human factor). In what follows, I start with the arrival of grizzlies in North America, the nature of the world within which they lived during the late Ice Age, the rapid changes that occurred at the terminal cusp of this Age, ending with the ensuing changes in distributions of brown bears. ( Much more to see on site )
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Post by brobear on Jul 8, 2022 6:30:24 GMT -5
North American Mammals of the Holocene:
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