Remarkable footage
One of the locations where I live features many interactions between black bears and dogs. I doubt the sort of scene shown in this footage is at all common. I've certainly never heard of such a thing. The bears seem indifferent to humans in most cases but with dogs there is a mutual caution that can turn to combative behaviour quickly (though rarely leading to death). I'm sure most dog owners know this well. Perhaps there are enough differences between polar bears and black bears that such an interaction is less stricking than it appears but I doubt it. Both the bears and the dogs must have had good meals recently.
These polar bears seem quite different from those mentioned in reports of polar ice reductions where incidents of polar bear cannibalism are often noted. E.g.:
http://www.cnn.com/2008/TECH/09/23/arctic.ice/index.html
Remarkable footage, VV. Thank you for postng. It's nice to know that nature has a peaceful side. Now if I saw cougars cavorting with dogs (minds out the gutter fellas!) I'd really stand up and notice. We have almost weekly reports of cougars attacking dogs even while walking with their humans. One elderly lady I talked with told of an encounter where her pooch barely escaped alive. Several of my coworkers have been stalked while riding their bicycles. When I almost ran over a bear during a ride he simply walked off into the woods. I doubt a cougar would have yielded ground so quickly.