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Post by OldGreenGrolar on Dec 4, 2019 9:11:09 GMT -5
Brown bears are more heavily built than polar bears which are in turn more heavily built than the short faced bears.
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Post by brobear on Dec 5, 2019 5:58:45 GMT -5
By Jagroar at www.deviantart.com/jagroar/gallery Bottom two bears - I would wager on the grizzly ( actually a cave bear ); at least a foot shorter but with a stocky build.
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Post by brobear on Dec 29, 2019 5:13:35 GMT -5
Quote from reply #145 from topic "Arctodus simus": In a recent study, the mass of six specimens was estimated, one-third of them weighed about 900 kg (1 short ton), the largest being UVP 015 at 957 kg (2,110 lb). Quote from reply#146 from topic "Arctodus simus": The Giant Short Faced Bear was 1,5 to 1,80 m (5 to 6 feet) tall at the shoulder and rose to an impresive 3 m (10 feet) when standing on its hind legs, it weighted 600 to 800 kgs (1320 - 1760 pounds) the giant was taller than a Polar Bear . iceage.museum.state.il.us/mammals/short-faced-bear-0 Females: 300-400 kg (660-880 lbs); Figuerido et al. 2010 Males: 800-1000 kg (1760-2200 lbs); Figuerido et al. 2010
The average mature male Arctodus simus probably weighed from 1600 to 1700 pounds! Most of the knowledgeable people that I am familiar with agree that the mature male Pleistocene grizzly averaged roughly 700 pounds. This is the size of an Alaskan peninsula brown bear. Big bears! But still less than half the weight of the giant. In fact, the giant outweighed the grizzly by half a ton. However, the giant she-bear was within the same weight range as the male grizzly. But there remain still some bear biologists who believe it possible that the grizzly, along with man-kind which showed up not long after the grizzly, played a major role in the extinction of the giant. They also believe that the American black bear played a part in the extinction of the Florida cave bear ( close relative of the Andean bear ).
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Post by brobear on Jan 8, 2020 5:22:07 GMT -5
Room for Thought: I have no doubts that Arctodus simus ruled the land wherever he lived up to the day of his extinction. However, I cannot help but to believe that there were some titanic battles between giant short-faced bear and an exceptional Pleistocene ( Bart-sized ) grizzly.
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Post by King Kodiak on Jan 8, 2020 13:05:41 GMT -5
"Room for Thought: I have no doubts that Arctodus simus ruled the land wherever he lived up to the day of his extinction. However, I cannot help but to believe that there were some titanic battles between giant short-faced bear and an exceptional Pleistocene ( Bart-sized ) grizzly. "
Yeah, that fight could had happened. That would had been a fight i would pay to see.
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Post by brobear on Jan 8, 2020 14:46:04 GMT -5
You know; we all try to look at animal face-off scenarios with complete logic. Logically, in a face-off between a 400+ pound Bengal tiger and a 200 ( at best ) female sloth bear, the bear should last no better than a matter of seconds. Also, when barren ground grizzlies ( in the 300 pound range ) invade polar bear territory, those little grizzlies should be simply shoved out of the way by the 1,000+ pound polar bears. No, I don't for a second believe that the grizzly dominated the giant; but the giant might have had a certain amount of respect for the smaller bear. The Arctodus she-bears especially. I would say that the giant dominated a carcass in perhaps 90% of situations. But a really big grizzly ( 1400 to 1600 pounds ) might hold his own through sheer aggression and dominate a kill.
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Post by King Kodiak on Jan 8, 2020 16:50:57 GMT -5
You know; we all try to look at animal face-off scenarios with complete logic. In theory yes, a male Bengal tiger would kill a female sloth bear in seconds, but the only face to face fight that we have on video, a tiny, skinny, female sloth bear lasted 15 minutes with a dominant adult male tiger.Also, when barren ground grizzlies ( in the 300 pound range ) invade polar bear territory, those little grizzlies should be simply shoved out of the way by the 1,000+ pound polar bears. I agree, in fact no animal dominated Simus in the Pleistocene. What we do know is that the one that adapted was Horribilis though, Simus disappeared. I agree, the much larger Simus most likely dominated kill sites most times.
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Post by brobear on Jan 10, 2020 15:57:14 GMT -5
It's like this; if no one had ever witnessed the meeting of barren ground grizzlies and polar bears, and you asked me what do I think would happen should some of those grizzlies, most adult males ranging within the 300 pound range, should wander up into the polar bear's domain, I would have thought that the aggressive polar bears would have viewed the grizzlies as food options. I would have expected the polar bears to make short-work of the grizzlies. What did happen though, surprised the bear experts. Therefore, we do not really know anything about the relationship between the Pleistocene grizzly and Arctodus simus. And, some paleontologists believe that the grizzly played a key role in the extinction of the giant bear.
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Post by brobear on Jan 11, 2020 9:22:43 GMT -5
Reply #150 - Quote: With an average body mass estimated at 700–800 kg. *My Conclusion: Result of your conversion: 750 kilograms is equal to 1,653.47 pounds (avoirdupois) = average weight of 1,650 pounds. *Note: The greatest weight recorded for a Kodiak bear in the wild is 1656 lb ( 751 kg ) for a male shot at English Bay. Now, consider that an exceptional boar Pleistocene grizzly is challenged over a carcass by a typical giant short-faced bear. These two great bruins are equal in weight - each weighing about 1600 pounds. Arctodus is taller. Ursus is broader across the shoulders. Your thoughts... ?
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Post by King Kodiak on Jan 11, 2020 10:00:07 GMT -5
Reply #150 - Quote: With an average body mass estimated at 700–800 kg. *My Conclusion: Result of your conversion: 750 kilograms is equal to 1,653.47 pounds (avoirdupois) = average weight of 1,650 pounds. *Note: The greatest weight recorded for a Kodiak bear in the wild is 1656 lb ( 751 kg ) for a male shot at English Bay. Now, consider that an exceptional boar Pleistocene grizzly is challenged over a carcass by a typical giant short-faced bear. These two great bruins are equal in weight - each weighing about 1600 pounds. Arctodus is taller. Ursus is broader across the shoulders. Your thoughts... ? This is just my opinion, but to be honest, The grizzly defends its carcass and a brief fight occurs. No one dies. Either one ends up leaving the fight. Depends on each individual specimen, sometimes horribilis leaves, sometimes Simus leaves.
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Post by brobear on Jan 11, 2020 12:53:05 GMT -5
Pretty much the way I have it pictured. The short-faced bear is used to having his way. How often do predators stand up to the giant and fight? We have no way of knowing. The giant will certainly test the grizzly's mettle. If the grizzly shows a lot of fight ( acts aggressively ) the short-faced bear just might walk way. Then again; we have no clues as to the aggressive behavior of the giant. We do know that the Pleistocene grizzly was highly aggressive according to the tales told by early American pioneers as the American Indians. Theoretically, the grizzly's bad disposition came from the grizzly's Pleistocene background.
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Post by King Kodiak on Jan 12, 2020 0:04:28 GMT -5
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Post by brobear on Apr 19, 2020 5:07:58 GMT -5
A quote from - Earliest Bear Ancestors - Basic Bear Evolution: Quote: A. simus disappeared at the end of the Wisconsin glaciation, perhaps due to competition with Ursus arctos (Kurten and Anderson 1974). These 2 bears, however, apparently co-existed in Beringia for about 100,000 years, so if competition was the leading factor, other conditions must have changed.
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Post by brobear on Sept 9, 2020 23:42:29 GMT -5
en.wikipedia.org/wiki/Dietary_biology_of_the_brown_bear Quote: The brown bear (Ursus arctos) is one of the most omnivorous animals in the world and has been recorded consuming the greatest variety of foods of any bear. As the giant short-faced bears began dying off towards the end of the Pleistocene, I believe that Ursus arctos owes its survival success to the combination of his omnivorous lifestyle ( wide range of food choices ) and his ability to hibernate.
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Post by King Kodiak on Mar 4, 2021 1:41:04 GMT -5
A Multivariate Analysis of the Ecology of North American Pleistocene Bears, with a Focus on [Arctodus simus]
Abstract
Pleistocene North America hosted a diverse collection of carnivores, including canids, felids, and bears. At least three species of Pleistocene bears are extinct (Arctodus simus, Tremarctos floridanus and A. pristinus), along with much of the North American megafauna. Earlier work on the axial skeleton and the appendicular skeleton of A. simus concluded that it was a superscavenger. This research is solid – but more ecological questions remain to be answered. What animals did it typically scavenge? How did it compete with other scavengers? What habitat did A. simus prefer? How did it interact with other carnivores, and specifically, with other species of bears? Was its extinction a result of competition with invading Eurasian ursine bears, or the consequence of carrion extinction? When the tremarctines were extirpated from North America, did the ursine bears expand their niches? These inquiries will not be answered by examining the animal’s morphology. Rather, they are best approached by statistically examining their entire ecosystem. The statistical analysis techniques employed in invertebrate research are rarely used in Pleistocene research or vertebrate paleontology due to the large sample sizes needed within a single site, but by looking at entire epochs, sufficient data can be acquired for analysis. This preliminary examination will focus on the degree to which North American Pleistocene ursine and tremarctine bears shared habitats, and what can be inferred from this about the cause of the tremarctine bears’ extinction in North America. The null hypothesis was that there was no significant competition between ursine and tremarctine bears during the Pleistocene. If this were the case, ursine and tremarctine bears would be segregated by cluster – that is, they would not be found in the same communities. Cluster analysis found that while some mammalian communities are associated with only one subfamily of bear, most clusters contained a mixture of tremarctine and ursine species. The null hypothesis is thus not supported by current study, and we cannot rule out competition from ursine bears as a major factor in the North American tremarctine bear’s demise.
www.researchgate.net/publication/313837841_A_Multivariate_Analysis_of_the_Ecology_of_North_American_Pleistocene_Bears_with_a_Focus_on_Arctodus_simus
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Post by brobear on Mar 4, 2021 2:00:42 GMT -5
Reply #74 - Quote: "....we cannot rule out competition from ursine bears as a major factor in the North American tremarctine bear’s demise."
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Post by OldGreenGrolar on Mar 7, 2021 23:12:31 GMT -5
I know this might sound a little bold but ursine bears might be more aggressive than tremarctine bears.
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Post by brobear on Mar 8, 2021 4:07:26 GMT -5
I know this might sound a little bold but ursine bears might be more aggressive than tremarctine bears. Aggression factor unknown. As for survival competition, in confrontations, Arctodus simus was too big for a grizzly to fight. Same goes for the American black bear and the Florida short-faced bear. We do know that the Ursus bears hibernated during the long bitter Winter months. This is a major survival tactic. Every Winter, there would have been more short-faced bear casualties than Ursus bears. This has not been proven, but I suspect that the Ursus bears had a much wider variation on food resources. There was a lot more food items on a Ursus bear's menu ( IMO ). As for direct competition ( fights ), I believe that both the black bear and the grizzly had more trouble from the big cats and dire wolves than from the tremarctine bears. The short-faced bears were ( IMO ) not hunters. *Edit and add: Did the short-faced bears dig for edible roots and tubers? Did they dig for burrowing rodents? Did they dig at all? Did the short-faced bear catch fish? Did they consume shellfish? Did they consume insects such as ants, termites, moths, or bees? Did they consume honey?
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