I've lived about 90 miles north of Yellowstone Park for the past 40 years. I have not heard of a single verified sighting of a grizzly bear north of I-90 in Gallatin or Park counties, MT since I've been here.

Any thoughts of mother bears kicking their offspring out to prevent interbreeding is total BS. Male animals will attempt to breed any female of their species that comes into heat. They don't care if the female is their sister, mother, or grandmother.

Montana FWP is continually live trapping problem bears and transplanting them in other area of the state. If the FWP bear biologists were concerned about mixing the genetics of Yellowstone and Glacier Park grizzlies, they could easily move male bears between the parks, and not have to wait several hundred years for bears from each Park to naturally mix.