Genetic testing has revealed that bears in Canada’s Banff National Park routinely cross the bridges and underpasses along the Trans-Canada Highway, evidence that the ecological corridors provide safe
passage along a busy roadway that otherwise threatens to fragment wildlife habitat. Using 420 wire snag “hair traps” and 497 rub trees at 20 crossings to collect hair from passing bears, researchers from Montana State University determined that 15 individual grizzly bears and 17 individual black bears used the passages over a three-year period. According to researchers, those accounted for about 20 percent of the park’s bear populations, suggesting the passageways are providing enough connectivity to maintain a healthy ecosystem for bears and other large mammals. Twenty-five passages were installed in the 1990s when the government widened a highway that includes a 100-mile stretch bisecting Banff.