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Who wins?
Pleistocene Polar Bear 10 (25%)
South American Giant Short-faced Bear 30 (75%)
Total Votes: 40
Pleistocene Polar Bear v South American Giant Short-faced Bear
Topic Started: Sep 16 2012, 05:53 PM (11,777 Views)
Taipan
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South American Giant Short-faced Bear - Arctotherium angustidens
Arctotherium is an extinct genus of South American short-faced bears within Ursidae of the late Pliocene through the end of the Pleistocene. They were endemic to South America living from ~2.0–0.01 Ma, existing for approximately 1.99 million years. Their closest relatives were the North American short-faced bears of genus Arctodus (A. pristinus and A. simus). The closest living relative would be the Spectacled bear (Tremarctos ornatus). Arctotherium was named by Hermann Burmeister in 1879. It was assigned to Tremarctinae by Krause et al. 2008.[2] A specimen of A. angustidens from Buenos Aires shows an individual estimated, using the humerus, to weight between 983–2,042 kg (2,170–4,500 lb), though the authors consider the upper limit as improbable and say that 1,588 kg (3,500 lb) is more likely, however, using the radious, the mass estimate shrinks to a maximum of 1,108 kg (2,440 lb). Independently of the method it is possibly the largest bear ever found and contender for the largest carnivorous land mammal known to science.

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Pleistocene Polar Bear - Ursus maritimus tyrannus
Ursus maritimus tyrannus was a very large fossil subspecies of the polar bear that descended from an Arctic population of brown bears. Its name in Latin means Tyrant Sea Bear. Initially the isolated brown bears were no different than the variations of brown bears of that time period. Because litters of cubs can show significant species variations in hair color and hair thickness, this gave certain individuals a survival advantage passed on each generation. Eventually skull changes and even changes in dentition occurred leading to the smooth and rather quick evolution of U. maritimus tyrannus. U. maritimus tyrannus was considerably larger then its modern relative. If everything is scaled out correctly from its remains, it would had been 183 cm (6 ft) at the shoulders, 3,6 m (12 ft) long and would have weighted an average of 1.2 tons (Ranging up to an estimated mass of 1,200 kg (2,600 lb)). Its tremendous size makes it even bigger than the other "largest" mammalian carnivores that ever lived, including Andrewsarchus, Agriotherium, and Arctodus simus. It's speculated that this gigantic bear would, due to its formidable size and strength, have preyed on mammoths which also lived during the time.

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yigit05
Sep 15 2012, 11:30 PM
pleistocene polar bear vs arctotherium
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Verdugo
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Correct me if i am wrong, but Arctotherium is the larger one here, not Ursus maritimus tyrannus  :-/
Edited by Verdugo, Sep 16 2012, 06:15 PM.
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Vodmeister
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Arctotherium would win here. It's genuinely larger, and in the bear world, size does mean almost everything.
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Megafelis Fatalis
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Taipan
Sep 16 2012, 05:53 PM
however, using the radious, the mass estimate shrinks to a maximum of 1,108 kg (2,440 lb)
I Didn't know that ..................
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Mauro20
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Arctotherium wins.
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Ursus arctos
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Vodmeister
Sep 16 2012, 06:16 PM
Arctotherium would win here. It's genuinely larger, and in the bear world, size does mean almost everything.

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DinosaurMichael
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The South American Giant Short-faced Bear wins in my opinion. It's alot larger and much stronger. Pretty much a huge weight mismatch.
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Taipan
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Depends on the weight estimate for Arctotherium. It could be a weight mismatch in favour of the Sth American GSFB!
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yigit05
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arctotherium win stronger bite,weight,paws
polar bear size avantage
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Vodmeister
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Ursus arctos
Sep 16 2012, 09:02 PM
Vodmeister
Sep 16 2012, 06:16 PM
Arctotherium would win here. It's genuinely larger, and in the bear world, size does mean almost everything.

There's quite a difference between chasing an animal away and killing it, don't you think?

If you honestly believe that if one animal retreats, that means victory for the one who holds his/her ground, then you surely have to accept the fact that a male grizzly lost to a female cougar roughly one-fourth his size, can you see that? rolleyes



Back on topic - Logically, Arctotherium would be quite a bit larger as it was estimated up to 1700 kg while "only" about 1200 kg for the Pleistocene Polar Bear. I don't there there was any terrestrial mammalian predator ever of what we know of who could defeat a boar Arctotherium in a face-off.
Edited by Vodmeister, Sep 17 2012, 04:57 AM.
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Ursus arctos
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Taipan
Sep 16 2012, 10:44 PM
Depends on the weight estimate for Arctotherium. It could be a weight mismatch in favour of the Sth American GSFB!
Depends on the weight estimate of the polar bear to.

If you compare the sizes of their bones, Arctotherium angustidens is obviously much larger.
Only a single specimen of both, and only a single leg bone for the polar bear.
485 mm ulna for U. m. tyrannus, vs 570 mm ulna for the Sth American GSFB.

Also, the radius estimates are much smaller than the others-but they were made by Viranta 1994's formulas, which are thought to underestimate the size of extinct bears in general. You may remember them being mentioned in Per Christiansen's article What size were Arctodus simus and Ursus spelaeus?
For example, Viranta suggested 319 kg for male cave bears.

I do think the humeral circumference estimates of Arctotherium angustidens are exaggerations though- I think the injuries exaggerated all these measurements, making the bear appear more robust than it actually was.
The humerus length-weight equations generated the following estimates:

Anyonge. 1993
Right: 1179.5 kg
Left: 1151.9 kg
Christiansen, 1999
Right: 1912.4 kg
Left: 1856.2 kg
Egi, 2001
Right: 1693.8 kg
Left: 1654.6 kg
Edited by Ursus arctos, Sep 17 2012, 05:16 AM.
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Vodmeister
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All I know is that size estimates for Arctotherium have varied between 543 - 2042 kg, or 1200 - 4500 lbs. Most recent size estimate suggests 1749 kg, or about 3820 lbs.
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Ursus arctos
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Vod, unless you think an entire camera team happened to be sitting prepared to catch that footage with multiple angled shots (including all those close ups) you can't disagree with the statement that footage was staged. Although some researchers did witness coyotes chasing off grizzlies, so something like that happening sounds reasonable enough.
Wildlife documentaries come with the promise that what you're seeing and hearing is genuine—but that's not always the case, according to a new book by a veteran environmental filmmaker. In Shooting in the Wild: An Insider's Account of Making Movies in the Animal Kingdom, Chris Palmer exposes some of the dirty secrets behind nature documentaries, like manufactured sounds and staged animal fights. Palmer tells Weekend Edition host Liane Hansen that after 30 years in the business, he had become haunted by what he had seen and felt the need for transparency.

"I've seen a lot of good things, a lot of great films," he says. "But I've also seen animal abuse, animal harassment, audience deception, the demonization of animals, like in Shark Week [and] Uncut and Untamed," shows which he says carry an anti-conservation message.

Palmer is guilty of deception himself. While working on an IMAX film about wolves, the film team found it was too hard to get shots of roaming wolves, so it went to a game farm and rented them. Palmer tells Hansen that his wife was outraged when she learned that the sound of water dripping off the paws of a grizzly bear in one of his films was actually the sound of an assistant ruffling his hand and elbow in a water basin. "He recorded those water sounds and then cleverly match[ed] it to the video that we shot with a long lens," he says.

The sound of an eagle's wings beating as it takes off majestically from the top of a mountain? "That sound will invariably be made by an umbrella opening and closing," Palmer says. Whenever a film shows a close-up of a big animal like a bear, Palmer says, the viewer should be on alert: Chances are high that the animal came from a game farm or has been trained. "When it plunges its head into the entrails of a dead elk it could be there are M&Ms that have been put into the elk so that the animal feed on it," he says. "It could be that it's been made hungry. It could be that behind the cameraman there's a trainer giving it signals."

This of course begs the question of how authentic do you think most hunting and fishing shows really are? Do you think they have a better or a worse track record for authenticity than straight nature shows? I mean, do you think Joe Cermele really catches all those fish, or is there some dude down there in the water with a bucket of chum? Discuss.

From here.

Fraud in 'Wildlife' Films! Wildlife film maker Marty Stouffer has been secretly staging nature scenes/treating animals cruelly, and so have been many other wildlife film makers! He built a hunting camp/hunted animals illegally. Alumnae of 'Wild America' plus film crew members and 3 animal suppliers, told about Stouffer's behind-the-scenes methods providing witness accounts of how he staged sensational kill scenes, including a fatal fight between a mountain lion and a lynx - animals that would rarely even cross paths in the wild! PBS investigation found fault with 15 shows in the 'Wild America' archives. In Stouffer's 'Dangerous Encounters' he staged a mountain lion attacking an apparently unsuspecting cross-country skier warning the viewers of recent increases in lion attacks, failing to explain that the scene is nothing more than a playful moment between a tame lion & his veterinarian owner!!! Even Ray Disney admitted in a Canadian TV program that his famous uncle dropped captured lemmings into a river to film their 'mass suicide'!!! Also exposed was how Perkings, for his 'Wild Kingdom' series, deposited a tame bear in a Florida swamp and proceeded to his 'heroic' rescue of the struggling animal, complete with helicopter/boat/lassos... Page admits: 'You simply cannot film the scenes without setting them up'!!! Burrowing animals or hiving insects are filmed in man-made equipment. Few viewers are naive enough to think film makers just 'happened' upon every scene in their 'documentaries'
From here.

The bear and cougar were both captive animals.




Vod
 
in the bear world, size does mean almost everything.


You haven't justified this statement, especially the qualifier "in the bear world" considering how much evidence we have to the contrary for bears compared to other families.

~~~

Regarding size, there has only been that one article ("The Largest Known Bear, Arctotherium angustidens, from the Early Pleistocene Pampean Region of Argentina: With a Discussion of the size and diet trends in bears", by Leioikdi G, Siuvekzibu abd Vkaube W, Schubert. Journal of Paleontology, 85(1), 2011, p. 69–75) on that bear, and it used estimates based on equations from several different earlier articles that made equations relating limb bone dimensions with body mass.

I don't know where the 543 kg estimate came from, but the article does have estimates for other specimens based on Viranta's radius equations:
MLP 00-VII-10-1 : 819.2 kg
MLP 10-21 : 414.9 kg
MLP 09-I-5-1 : 804.5 kg
MACN 9609 : 804.5 kg

For the adult male estimates were 1,108 kg and 1,094 kg for the left and right, respectively (I think).
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Vodmeister
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Quote:
 
You haven't justified this statement, especially the qualifier "in the bear world" considering how much evidence we have to the contrary for bears compared to other families.

In the insect world for example, size doesn't mean nearly as much because insects are so different/variant from each other that I've seen many large bugs being killed by smaller ones countless times. For example, I've seen a hornet kill a tarantula much larger.

Another good example would be theropods. I'd favor a Tyrannosaurus over a Spinosaurus, even though the Spinosaurus was about 2.5 times larger. Why? Because the T-Rex, in my opinion, was much better armed and more powerful build than the slender and more fragile Spino. I'm not trying to start a dinosaur debate here.

Bears on the other hand, like felines for example, have all their species & subspecies far too closely build to each other for anything other than size/strength to have any major effect in a face-off. Therefore, the larger bear will almost always prevail over the smaller one, no matter in what way you put it.
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GrizzlyBear
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Arctotherium is the king of all bears.
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