Another 'polar bears are in trouble' story….yawwwn

Are Polar Bears even a real species?
Polar bears are essentially white grizzly bears… Setting aside the fatally flawed premise that Arctic Sea ice is vanishing and ignoring the fact that Polar Bears sailed right on through the much warmer Holocene Climatic Optimum… If Polar Bears and Grizzlies can interbreed, producing genetically viable offspring, they are of the same species. Therefore, as long as Grizzlies, Kodiaks and other brown bears live, Polar Bears, as a species, cannot go extinct.
The traditional definition of “species” as applied to sexually reproducing animals is: If two animals can mate and produce genetically viable offspring, they are of the same species.
A horse and a donkey can mate and produce a mule; which normally cannot reproduce. A mule is not genetically viable. Therefore horses and donkeys are separate species.
A Collie and a Dachshund can mate and produce a really odd looking dog; which can reproduce. Collies and Dachshunds are of the same species.
Using the traditional definition, Polar Bears and Grizzlies are of the same species.
The modern, revisionist definition of species is: If two organisms would not normally mate and produce offspring; they are of separate species. Using the modern, junk science definition. Roseanne Barr is of a different species than 99.9999% of all human males.
The “experts” classified Polar Bears as a unique species because they looked and acted different than Brown Bears. This was a mistake…

The Brown Bear: Father of the Polar Bear?
Article #1314
by Ned Rozell
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This article is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Ned Rozell is a science writer at the institute.
There’s something different about the brown bears of Southeast Alaska’s ABC islands.
They look like your average Alaska grizzly: milk-chocolate colored fur, a humped back, and a size and reputation that gives humans something to fear when walking the wilds of Alaska.
The difference in the brown bears of the ABC (Admiralty, Baranof and Chichagof) islands isn’t visible. It’s in their DNA. Researchers found the bears are more closely related to polar bears than they are to other brown bears.
The bears’ baffling background was discovered when Gerald Shields and Sandra Talbot of the University of Alaska Fairbanks Institute of Arctic Biology began analyzing the DNA of brown bears from around the world. Talbot, a graduate student, extracted DNA (deoxyribonucleic acid, the genetic information warehouse in the chromosomes of every living cell) from hundreds of Alaska brown bears. Starting with slivers of kidney or muscle tissue attained from hunting guides, Talbot used a process called polymerase chain reaction to copy tiny fragments of DNA millions of times.
When the DNA was in a readable form, Shields, a molecular evolutionary biologist, saw the DNA from brown bears on the ABC islands brown bears was unique when compared to brown bears anywhere else on the planet. Their closest relative is an unlikely one–the polar bear.
A polar bear’s white coat, meat-only diet, and preference to live near and on sea ice make it hard to mistake for a brown bear. But Alaska’s two largest bear species are closely related–so closely that brown and polar bears have mated in zoos and the union has resulted in fertile offspring. According to the Alaska Department of Fish and Game’s “Wildlife Notebook Series,” both types of bear had a common ancestor that was neither brown nor polar bear. As each adapted to different environments, the bears developed enough unique characteristics that they looked and acted like separate species.
With DNA evidence, Shields and his colleagues have launched a new hypothesis–brown bears may have appeared first; polar bears may have arisen from brown bears that wandered north and, over thousands of years, began to sprout white fur and teeth that were better for ripping apart seals than munching berries.
[…]
http://www2.gi.alaska.edu/ScienceForum/ASF13/1314.html

Polar Bears probably evolved as a distinct subspecies of Brown Bears because a group of Sangamonian (Eemian) brown bears headed north during warm phases of the last interglacial, just like these Grizzlies are…

Grizzly Bears on Ice
At the northern edge of the species’ range, a growing number of grizzlies are eking out a living in territory traditionally dominated by polar bears
02-01-2006 // Ed Struzik
ABOUT 50 MILES NORTH of tree line in Canada’s western Arctic, Andrew Derocher picked up the tracks of four grizzly bears following a herd of caribou across hard snow and ice toward the coast. Derocher, a University of Alberta biologist, wasn’t sure whether the tracks had been left by a family or by a male following a female with two cubs. If it turned out to be the latter, he said, the mother and offspring could be in trouble. Contrary to what may appear in popular movies and books, a lone male grizzly is more likely to kill and eat bear cubs than befriend them.
[…]
Barren ground grizzlies are among the most enigmatic of Arctic mammals. Few in number and rarely seen, they are as much myth as reality.
[…]
What grizzlies are actually doing up there in the kingdom of their great white cousins is not clearly understood. Biologists have long considered the differences between the two bears significant enough to warrant separate species status. Physical distinctions are obvious: Polar bears are white rather than brown, which helps camouflage the predators from their prey on the sea ice. They are also generally larger, and have heads and bodies that are much more elongated, and therefore better adapted to penetrate seal lairs. Their larger, sharper teeth allow them to tear up seals efficiently, and shorter claws and larger feet make it easier for polar bears to travel on sea ice and swim across great expanses of water.
Many Eskimos believe that rising temperatures in the Arctic explain why grizzly bears–as well as marten, wolverines and several other species of birds and mammals–are showing up in extreme northern places where they were rarely, if ever, seen before. Global warming, they say, is creating conditions that are more favorable for these animals, at least in the short term.
While most scientists see that idea as a genuine possibility, experts like Canadian Wildlife Service biologist Ian Stirling, who has studied polar bears for more than 30 years, suspects that some grizzlies have always been venturing onto the ice. Perhaps, Stirling says, “what we’re witnessing today is behavior similar to the evolutionary process that resulted in polar bears filling a rich but vacant niche as supreme predator of the sea ice.”
[…]
http://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2006/Grizzly-Bears-on-Ice.aspx

I Polar Bears and Grizzlies are different species, then Chihuahuas and Siberian Huskies are different species.
If you look at Fig. 1 of Miller et al., 2006, you’ll see that Polar Bears fit right into Clade 2 with the ABC Islands Brown Bears (ursus arctos sitkensis). Barnes et al., 2002 featured a similar diagram that included fossil subspecies of ursus arctos; once again, Polar Bears fit right into ursus arctos…
http://www.sciencemag.org/content/295/5563/2267/F1.large.jpg
http://www.webpages.uidaho.edu/~joyce/davis/Miller%20bear.pdf
http://www.sciencemag.org/content/295/5563/2267.full
There has never been any scientific basis to categorize Polar Bears as a distinct species. It is clearly a subspecies of ursus arctos.