Who would win: polar bears, grizzlies or black bears?

An age-old question has finally been answered.
A grizzly bear is likely able to beat both a polar bear and a black bear in a battle for survival.
Researchers at the University of Saskatchewan has been examining how climate change affects various species of bears in Canada, according to an article in the University of Saskatchewan’s On Campus News.
Douglas Clark, a conservation scientist at the U of S’s School of Environment and Sustainability, is the lead researcher on the project, w