Were they taken out of the zoo?

I don't think it's the same bears. I suspect the "main" bears that the camera follows is intercut with footage from a zoo or involving similar-looking bears.

The bears in the den at the start of the movie aren't the same ones as in the rest of the film. The den was filmed under controlled conditions in captivity. If they stuck a camera into a wild mother bear's den she would eat her cubs, then the film makers.

If they dropped a family of zoo-raised bears into the Alaskan wilderness they would be dead in days.

I can't believe how dense people are. You really believe they wound take bears out of captivity and just stick them in the wild? Please use your brain, obviously they didn't do that and the bears wouldn't of survived or known where to go.