[NAEP] [Fwd: Hybrid bears rare, likely not new in Arctic]

[Dawn Wiseman]

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Subject: 	Hybrid bears rare, likely not new in Arctic
Date: 	Sun, 28 May 2006 23:28:02 -0800
From: 	M. Pamela Bumsted, Ph.D. <hlthenvt at mochamail.com>
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"NED ROZELL
Hybrid bears rare, likely not new in Arctic

NED ROZELL
ALASKA SCIENCE

Published: May 28, 2006
Last Modified: May 28, 2006 at 05:54 AM

When he heard the news of a grizzly-polar bear hybrid shot in Canada's 
Arctic last month, Tom Seaton thought back to an unusual polar bear hide 
he'd once seen at Nelson Walker's home in Kotzebue.

"He had two polar bear rugs in his house -- one was a huge one, and the 
other was special; it had lots of brown in it," Seaton said. "It looked 
like a regular polar bear, but for every square inch of hide, 5 to 20 
percent of the hairs were brown instead of white."

Walker, who has since died, was a polar bear hunting guide in the village; 
Seaton was then a teenage hunter who loved to listen to Walker's stories. 
He's now a biologist with the Alaska Department of Fish and Game in Fairbanks.

Because he had heard that polar bears and brown bears had bred successfully 
in a zoo, Seaton was pretty sure Walker's white-and-brown hide was from the 
mating of a polar bear and a brown bear.

That combination of large bears is so rare that DNA testing of the hybrid 
bear shot recently off Banks Island in Canada's high Arctic proved for the 
first time that a wild bear had a polar bear as its mother and a grizzly as 
its father.

An Associated Press reporter wrote that the bear had brown patches on its 
white coat, long claws, and the humped back of a grizzly.

Biologists say the merger is unlikely because the two species don't 
interact very much -- barren-ground grizzlies of the Arctic hibernate 
during much of the time polar bears have access to land.

Polar bears are often far out on the sea ice when they're ready to breed, 
but people sometimes see them on land in summer, as was the case in 1990 
when oil exploration workers saw a polar bear 50 miles inland from the 
Beaufort Sea coast.

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 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.

The carpet of tracks on the snow looked like the bears could have mated, 
Shideler said.

"The next year a helicopter pilot saw a female with darker cubs," he said. 
"And (hybrids) have been reported quite a few times by Natives (of Canada's 
Arctic)."

Biologists don't think "grolar bears" could threaten either species; a 
hybrid probably wouldn't forage on land as well as a grizzly bear, and a 
mottled brown coat wouldn't be the best camouflage on sea ice.

Ned Rozell is a science writer at the Geophysical Institute, University of 
Alaska Fairbanks. He can be reached by e-mail at nrozell at gi.alaksa.edu.

"
http://www.adn.com/life/story/7777398p-7690315c.html