All about Bears

[bob]

The polar bear is the largest of the extant bears (DeMaster and Stirling 1981). In Hudson Bay, the mean scale weight of 94 males >5 years of age was 489 kg. The largest bear in that group was a 13-year-old, which weighed 654 kg (Kolenosky et al. 1992). The heaviest bear we have weighed in Alaska was 610 kg, and several animals were heavy enough that we could not raise them with our helicopter or weighing tripod. Some animals too heavy to lift have been estimated to weigh 800 kg (DeMaster and Stirling 1981). Females are smaller, with peak weights usually not exceeding 400 kg. Total lengths of males in the Beaufort Sea of Alaska ranged up to 285 cm. Such an animal may reach nearly 4 m when standing on its hind legs and is 1.7 m shoulder height when standing on all four legs. Chest girth for large males is close to 200 cm. Although smaller, females in the Beaufort sea were as long as 247 cm with chest girths up to 175 cm. Only prehistoric polar bears and the giant short-faced bear (Arctodus spp.) of the Pleistocene were of greater stature than today's polar bears (Kurt´en 1964; Stirling and Derocher 1990).


Brown Bear, Polar Bear and a Grizzly Bear

[bob]

a polar bear is no match for a brown bear in a fight, as u can see the slender neck, inferior shorter claws, less robust skull etc...they r also generally less aggressive

[bob]

notice the less bulky skull of the white bear


notice that in all these pics, the brown bears appear much more impressive...above, the white bears congrgate together, none dare to go near the big brown bear

[bob]

UAF scientists doing genetic testing about a decade ago found that grizzly bears may be the ancestral fathers of polar bears, which over many thousands of years evolved to life on sea ice by developing all-white coats, furry feet, and teeth designed to rip seal flesh. People sometimes see the two bears together at whale carcasses, such as at a bowhead whale boneyard outside Kaktovik, where in fall both polar and grizzly bears feast on the remains of whales harvested by villagers. Those who have seen the bears there say that the grizzlies, often smaller than the polar bears, dominate the encounter

“They are two very different animals as far as behavior goes,” said Geoff York, a polar bear researcher at the USGS Science Center in Anchorage. “When a brown bear comes in at the bone pile, it chases off all the polar bears.”

Dick Shideler, a biologist at the Alaska Department of Fish and Game in Fairbanks who studies the farthest-north grizzly, has documented grizzly bears on the northern sea ice off Alaska’s coast.

“We’ve radio collared a grizzly bear who hunts seals in the spring,” Shideler said. “Our pilot has tracked him on the ice, going from hole to hole. He’s figured it out.”

Shideler also said biologists from the Northwest Territories have shared reports of what could have been hybrid bears in the past.

“There was a grizzly up there towards Banks Island that killed a bunch of seals, and (a pilot) tracked it and saw its tracks intersecting with those of a polar bear,” he said."

www.gi.alaska.edu/ScienceForum/ASF18/1803.html

[bob]

Ahpun is a female polar bear that was orphaned as a cub in the spring of 1998. Her mother was shot and killed by a fisherman in self defense when he accidentally came to close to the den area. Ahpun was held briefly in Point Lay, a village community nearby. The U.S. Fish and Wildlife Service then sent her by plane to our zoo in Anchorage as a permanent home for her. She initially lived with Oreo, a female brown bear cub that was also orphaned at around the same time. They lived together until 2003, when they became slightly aggressive toward each other. Oreo now lives with Jake (our male Kodiak brown bear) and Ahpun is living in her own exhibit.

[brotherbear]

This is some very interesting information. Thank you~

[Deleted]

Oct 18, 2009 0:21:10 GMT -5 bob said:

The polar bear is the largest of the extant bears (DeMaster and Stirling 1981). In Hudson Bay, the mean scale weight of 94 males >5 years of age was 489 kg. The largest bear in that group was a 13-year-old, which weighed 654 kg (Kolenosky et al. 1992). The heaviest bear we have weighed in Alaska was 610 kg, and several animals were heavy enough that we could not raise them with our helicopter or weighing tripod. Some animals too heavy to lift have been estimated to weigh 800 kg (DeMaster and Stirling 1981). Females are smaller, with peak weights usually not exceeding 400 kg. Total lengths of males in the Beaufort Sea of Alaska ranged up to 285 cm. Such an animal may reach nearly 4 m when standing on its hind legs and is 1.7 m shoulder height when standing on all four legs. Chest girth for large males is close to 200 cm. Although smaller, females in the Beaufort sea were as long as 247 cm with chest girths up to 175 cm. Only prehistoric polar bears and the giant short-faced bear (Arctodus spp.) of the Pleistocene were of greater stature than today's polar bears (Kurt´en 1964; Stirling and Derocher 1990).


Brown Bear, Polar Bear and a Grizzly Bear

What is the story behind the picture above? Did a fight acctually occur.
Also while the grizzlies are generally dominant in feeding areas, wouldn't a large polar bear acctually win in a fight to death given its much heavier weight?

[Deleted]

Oct 18, 2009 0:24:36 GMT -5 bob said:

a polar bear is no match for a brown bear in a fight, as u can see the slender neck, inferior shorter claws, less robust skull etc...they r also generally less aggressive

There was data posted on carnivora saying that the polar bears (equal to hippo's) bones are denser than that of brown bears (equal to lions and rhinos).
I believe that ursus artos has that data yet others say the opposite.
Yet in that data, the semi aquatic or aquatic mammals seems to have denser bones than terrestrial mammals generally.