An adult male grizzly bear might live as far as 300 kilometers from his cubhood home. Mountain lions have been found up to 480 kilometers away, and grey wolves as far as 917 kilometers from their birth places. Widespread movement is part of a carnivore's nature, and it contributes to a healthier gene pool, Craighead continued. However, animals find it harder to disperse when people move into their habitat and alter it with roads, logging, mining and subdivisions. Cougars, for one, need cover, which means they don't like to cross clear-cut areas.
Grizzly bears tend to avoid areas that contain more than one mile of road in one square mile.
They are getting isolated in smaller and smaller fragments. The world has seen dramatic changes in its natural habitats, but it's not too late to help animals continue their normal dispersal habits in the Northern Rockies, Craighead said. We still have most of the species we started with. We still have relatively healthy populations. Craighead has been working for the past three years on a project to identify and analyze the remaining areas of natural habitat and possible connections between them in the Northern Rockies.