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Bears of the Pleistocene

India brotherbear Offline
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( This post was last modified: 01-31-2018, 03:35 PM by brotherbear )

I believe Artodus and also Arctotherium both to have been omnivores who leaned more heavily towards a meat diet. I view them as perhaps the ultimate kleptoparasite/scavengers.
I will edit and add: I also believe that the Pleistocene grizzly was an omnivore which was more predator than scavenger.
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Venezuela epaiva Offline
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( This post was last modified: 02-12-2018, 07:35 AM by epaiva )

Cave Bear paw credit to @skeletoes_
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United Kingdom Spalea Offline
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@brotherbear :

About #281: I thought again the hypothesis you had raised, namely that the Arctodus Simus was a so dreaded predator that it provoked the scarcity of the North America fauna, especially as concerns the other big predators...

That isn't possible because you also noticed an anatomical weakness: he seemed to be unable to swiftly "made a sharp turn " when running at speed. If it is true the other predators would take advantage of it by harassing the ursid during each confrontation around a corpse... And then the ursid's life became impossible. Impossible to sustain such torments. Just try to imagine how, for the Arctodus Simus, it could be hard to endure a pack of wolwes harassing or biting the back of the knees if this was so difficult for him to twirl around at each bite... And I don't evoke lions.

If it was so, the Arctodus Simus sustaining this anatomicla weakness and being a pure scavenger, this ursid had to learn to share the corpses.

If the arctodus being a scavenger needed a reduced amount of food, how could his existence provoke a scarcity of the other predators (American lions, sabertooth cats, wolwes and so on.) ? That is contradictory.

If the Arctodus Simus was a pure predator, the competition would be intensified: the other predators learn to interact with a such powerful, but solitary, opponent.

For these reasons, I think the arctodus Simus wasn't a pure scavenger, and didn't sustain the anatomical weakness you evoked (the life would become impossible for him in that case).

The only things which are able to - naturally - provoke the scarcity of the fauna are the climatic changes. I don't speak about men.
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India brotherbear Offline
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( This post was last modified: 02-12-2018, 06:28 PM by brotherbear )

Spalea - I agree.
I will edit and add from post #282: I believe Artodus and also Arctotherium both to have been omnivores who leaned more heavily towards a meat diet. I view them as perhaps the ultimate kleptoparasite/scavengers.

I will edit and add: I also believe that the Pleistocene grizzly was an omnivore which was more predator than scavenger.
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India brotherbear Offline
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Arctodus simus - compare with polar bear and grizzly: 
 

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United States GrizzlyClaws Offline
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The largest skull for Arctodus simus is 521 mm long and 364 mm wide, whereas the largest skull for Ursus ingressus is 571.4 mm long, but I don't think its width nor height can match that of Arctodus simus. So I guess the overall volume of the skull might be similar for these two Ice Age Titans.
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Venezuela epaiva Offline
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( This post was last modified: 03-31-2018, 11:24 PM by epaiva )

Credit to deviantart.com

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India brotherbear Offline
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( This post was last modified: 03-31-2018, 11:46 PM by brotherbear )

...Wiki.

Adult Kodiak bear.
The size range for females (sows) is from 181 to 318 kg (399 to 701 lb), and for males (boars), it is 272 to 635 kg (600 to 1,400 lb). Mature males average 477–534 kg (1,052–1,177 lb) over the course of the year,and can weigh up to 680 kg (1,500 lb) at peak times. Females are typically about 20% smaller and 30% lighter than males, and adult sizes are attained when they are 6 years old. Bears weigh the least when they emerge from their dens in the spring, and can increase their weight by 20–30% during late summer and fall. Captive bears can sometimes attain weights that are considerably greater than those of their counterparts in the wilderness.

An average adult male measures 244 cm (8 ft 0 in) in length, and stands 133 cm (4 ft 4 in) tall at the shoulder. The largest recorded wild male weighed 751 kg (1,656 lb), and had a hind foot measurement of 46 cm (18 in).A large male Kodiak bear stands up to 1.5 m (4.9 ft) tall at the shoulder, when it is standing on all four legs. When standing fully upright on its hind legs, a large male could reach a height of 3 m (9.8 ft). The largest verified size for a captive Kodiak bear was for a specimen that lived at the Dakota Zoo in Bismarck, North Dakota. Nicknamed "Clyde," he weighed 966 kg (2,130 lb) when he died in June 1987 at the age of 22. According to zoo director Terry Lincoln, Clyde probably weighed close to 1,090 kg (2,400 lb) a year earlier. He still had a fat layer of 9 in (23 cm) when he died.

Kodiak bears are the largest brown bear, comparable in size to polar bears. This makes Kodiak bears and polar bears both the two largest members of the bear family and Kodiak bears the largest extant terrestrial carnivorans.
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India brotherbear Offline
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The Florida cave bear - https://www.floridamuseum.ufl.edu/florid...loridanus/ 
 
Quick Facts
Common Name: Florida spectacled bear
Much more common as a fossil in Florida than the living black bear.
Thought to be primarily a herbivore like the living South American spectacled bear.
Sometimes called the "Florida cave bear" but they are not closely related to the European cave bear, nor is there fossil evidence of a dependence on caves for denning. 
 
Age Range
  • In Florida, this species is restricted to the Rancholabrean North American land mammal age (late Pleistocene Epoch). There are a few published records of Tremarctos floridanus from the Irvingtonian and Blancan NALMAs (early Pleistocene epoch) in Western North America, but their species level classification needs confirmation.
  • About 250,000 to 11,000 years ago in Florida, but possibly up to 2 million years ago in western North America.
Scientific Name and Classification

Tremarctos floridanus Gidley, 1928

Source of Species Name: The species name refers to Florida, where the first described specimen of the species was found (Gidley, 1928).

Classification: Mammalia, Eutheria, Carnivora, Caniformia, Arctoidea, Ursida, Ursoidea, Ursidae, Tremarctinae

Alternate Scientific NamesArctodus floridanus; Tremarctos mexicanus
Overall Geographic Range 
 
Fossils of this species have also been recorded in several localities in southern North America along the Gulf Coast, New Mexico, Mexico, Tennessee, and Georgia (Guilday and Irving, 1967; Kurtén and Anderson, 1980). The type locality is the Golf Course locality in Melbourne, Florida (Gidley, 1928).
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India brotherbear Offline
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Tremarctos floridanus

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India brotherbear Offline
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( This post was last modified: 04-01-2018, 12:14 PM by brotherbear )

The cave bear who wasn't a cave bear... Tremarctos floridanus
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Florida short-faced bear, Florida cave bear (Tremarctos floridanus Gidley, 1928)



Order: Carnivora

Family: Ursidae ( the Florida cave bear was a grizzly-size short-faced bear ).

Dimensions: length - 2,2 m, height - 100-120 сm, weight - 150-300 kg

Temporal range: from the Pliocene - Holocene epoch of North America (4.9 million — 11,000 years ago)

Length ... 2.2 m = ( 7 feet 3 inches ).
height ... 120 cm = ( 3 feet 11 inches ).
weight ... 300 kg = ( 661 pounds ).
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India brotherbear Offline
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( This post was last modified: 04-01-2018, 12:15 PM by brotherbear )

Concerning the grizzly and the Pleistocene predators: Epiphany... I am having second thoughts on the entire intraspecific relationship teachings about Pleistocene predators of N. America. Besides the grizzly, there were three large bear species living in N. America, the black bear, the vegetarian Florida cave bear, and the giant short-faced bear. Now, I believe that the giant could chase any other predator from a carcass. But, I do not consider the giant to be a predator. He simply wasn't built for chasing down large prey animals. Besides, there were a multitude of large predators doing the hunting and killing which provided meat for the giant. Therefore, it was a simple matter for the grizzly to simply stay out of the giant's space.
No, not the giant bear. It was the wolves, both grey wolf and dire wolf which made life drastically hard for the she-bear with cubs. And, it were the big cats that hunted and killed sub-adult grizzlies. Giant jaguar, scimitar cat, atrox lion, and prides of saber-toothed cats. It probably was not the giant bear that preyed upon the grizzly, but rather the large full-time predators. Just as with the Amur tiger and the Ussuri brown bear in the R.F.E., the big cats of Pleistocene N. America probably preyed upon juvenile grizzlies and perhaps on occasion an adult she-bear. Even the occasional mature grizzly boar might possibly have fallen victim to a pride of saber-tooths from time to time.
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India brotherbear Offline
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Life is very much a financial challenge to me right now, but in time I plan to order this book by an author I respect. 
                                                                                               
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Venezuela epaiva Offline
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( This post was last modified: 04-03-2018, 08:42 PM by epaiva )

Aproxímate Dates of Origin of the Species of Bears
Book Bears of the World - Lance Craighead

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U
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United Kingdom Spalea Offline
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(04-01-2018, 12:13 PM)brotherbear Wrote: Concerning the grizzly and the Pleistocene predators: Epiphany... I am having second thoughts on the entire intraspecific relationship teachings about Pleistocene predators of N. America. Besides the grizzly, there were three large bear species living in N. America, the black bear, the vegetarian Florida cave bear, and the giant short-faced bear. Now, I believe that the giant could chase any other predator from a carcass. But, I do not consider the giant to be a predator. He simply wasn't built for chasing down large prey animals. Besides, there were a multitude of large predators doing the hunting and killing which provided meat for the giant. Therefore, it was a simple matter for the grizzly to simply stay out of the giant's space.
No, not the giant bear. It was the wolves, both grey wolf and dire wolf which made life drastically hard for the she-bear with cubs. And, it were the big cats that hunted and killed sub-adult grizzlies. Giant jaguar, scimitar cat, atrox lion, and prides of saber-toothed cats. It probably was not the giant bear that preyed upon the grizzly, but rather the large full-time predators. Just as with the Amur tiger and the Ussuri brown bear in the R.F.E., the big cats of Pleistocene N. America probably preyed upon juvenile grizzlies and perhaps on occasion an adult she-bear. Even the occasional mature grizzly boar might possibly have fallen victim to a pride of saber-tooths from time to time.

I take back your last sentence: "Even the occasional mature grizzly boar might possibly have fallen victim to a pride of saber-tooths from time to time."

Let us imagine a pride of hungry atrox lions patrolling the deserted snowy, beaten by the winds, landscape of the North American: 2 or 3 males, weighing between 300 and 350 kilos, 3 or 4 females between 180 and 250 kilos. Honestly, even a full mature male grizzly, weighing 400- 500 kilos (I imagine the Pleistocene grizzlys, being not yet harassed by the human predation, noticeably bigger than the extant ones), would flee swiftly such a coalition.

Perhaps, I am overrating the predation capacities of the atrox lions, but, apart their big size, they were endowed with a big cranium, showing so a bigger brain than the extant big pantera felids' one. A fact is: we have found a lot of sabertooth cats well preserved in the quicksand where they got stuck, but very few atrox lions in the same case. Perhaps these felids didn't fall into these traps.

This is the possibility that the pride of atrox lions took progressively the place of the sabertooth cats, becoming so the main pure predators within the Pleistocene of the North America. The giant short-faced bear being the ultimate scavenger, the only one able to rebel against them around a big corpse.
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