From the Vancouver Sun.
Remember, one was killed in 2006 that set off a firestorm on the internet and the Carnivore conservation community.
Polar bears are derived from brown bears that have evolved to utilized the Arctic ice sheets to hunt for food. They hunt ice breeding seals and cetaceans that are trapped by the ice.
They are more specialized than the various forms of brown bear are, and if the ice sheets disappear or become available for only a very short period, the polar bear will disappear.
But because they can produce fertile offspring with brown bears, it is likely that some of their genes will filter into that species.
well this gets back to “what’s a species” doesn’t it? Sure polar bears are distinctive – in coloration, behavior and habitat. But obviously there ARE “cream/whitish” grizzly “brown bears” and obviously the two are related. So is the polar /grizzly more distinct than a Min Pin and a Great Dane? Nope. The one was “manufactured by Nature” the other “manufactured by man” but you don’t get a direct minpin/Dane cross without an extremely unusual circumstance. You can find a continuium. That there isn’t a clear continuium that was obvious for polar/grizzly bears may be more due to the extermination/extinction events of the Pleistocene -current period than due to a “no overlap” seperation of the two species. The current evidence is that polar bears are a recent diversification from grizzly/brown bears. Recent is relative of course, but their existence requires “just” enough ice to allow hunting of seals, etc without “too much” ice preventing seals, etc from using the artic areas as pupping grounds. As such it was always an extremely specialized species and unlikely to last long in the scheme of things.
vr, Peggy Richter
I’m often troubled with the polar bear as a species.
In an earlier draft of this post, I said that the polar bear was nothing more than a modified brown bear.
There are some populations of brown bear that are more closely related to polar bears than to other brown bears.