Polar bears vs Grizzly bears

I read an interesting article in the Alaska Dispatch News which examined interactions between arctic grizzly bears and polar bears. They found that although polar bears are larger, they tend to leave food sources when grizzly bears are around. This may be because polar bears typically spend a lot of time on sea ice without the need to be aggressive towards competitors. Of concern is that the relatively passive nature of polar bears may be detrimental considering these animals are increasingly spending more time foraging on land during the summer and fall months.

North Slope bone pile in Alaska. USFWS

It is thought that grizzly bears evolved into polar bears as the climate cooled. It is interesting, therefore, that scientists and hunters are increasingly coming across "Pizzly" or "Grolar" bears which, as the names imply, are grizzly and polar bear hybrids. Second generation pizzly bears have also been discovered. Hybridization is one strategy to speed up adaptation, which is important for a polar bear living in a warming environment.

So does this mean that polar bears will evolve back into grizzly bears?

Image of a "pizzly bear" captured by Steven Kazlowski from www.archive.onearth.org

Sources

Alaska Dispatch News

http://www.adn.com/article/20120426/more-polar-grizzly-hybrid-bears-kil…

PBS

More like this

A few weeks ago I mentioned that there is some debate as to the taxonomy of the Polar Bear; specifically, as to whether it was simply a clade of the Brown Bear species. Interesting, I note that today a Polar Bear-Grizzly hybrid was shot in Canada: There have long been stories of oddly coloured…
One my friends lives outside of Anchorage, Alaska and recently had a black bear pay a visit to her backyard. Now her preschoolers are obsessed with bears. Minnow too has a bit of a bear obsession at the moment, though she hasn't seen any bears in their natural habitat. At school, she's been reading…
A grizzly bear (the black dot in the middle of the photo) walking near the treeline in Yellowstone's Hayden Valley. The quiet of my evening wildlife watching was suddenly broken by a thick Boston accent. "Oh my gawd! Look! It's a grizz! That's the last animal I needed to see! It's a grizz!" He was…
I have pointed to the fact that mtDNA genetics has suggested that the polar bear is actually a derived lineage of brown bears. And, more specifically, that some extant lineages of brown bears share a more recent common ancestor with polar bears than other brown bears. In other words, brown bears…