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| a grizzly sow and cub cross overpass in Banff NP |
Now that there are forty-four wildlife crossings in Canada's Banff National Park, both species of North American bear are crossing the road. Of course curious minds want to know why since chickens have already piqued their interest.
US Person allows such persons one guess. Hint: it's not for food! Yes, friends, bears cross the road to meet mates according to researchers at Montana State University. They gathered 10,000 hair samples from black and grizzly bears and tracked the flow of genes. Their study was published in the "Proceedings of the Royal Society B". This study according to one of the researchers is the first time science has shown animals using the man-made crossings are breeding on the other side
[photo courtesy MSU]. This is good news since crossing the road ensures populations either side of the human barrier are not genetically isolated. The study is the best evidence yet that crossings work and are beneficial to wildlife. The Canadian crossings are the most extensive network of wildlife crossings on Earth. Obviously, the crossings reduce collisions with motorists too.
The study was the final paper in a series conducted since 1996 studying the impact of Trans-Canadian highway crossings on bears Individual bears showed more comfort than others in using the man-made structures. One male black bear was particularly enthusiastic. Genetic testing revealed he mated with five different females and sired 11 cubs. As expected, black bears seemed much less wary of human construction than grizzlies. 47% of black bears used the crossings while only 27% of grizzlies crossed the highway. DNA was extracted from hair samples collected at wire snares and compared to samples collected throughout the surrounding forest on both sides of the highway. The millions it cost to construct overpasses for wildlife is apparently well spent as far as bears are concerned.