Major highways are a hard cross to bears

 作者:徐术     |      日期:2019-04-04 09:07:08
By Bob Holmes WHEN does the grizzly bear cross the road? Answer: Very rarely – and that’s bad news for bears in the northern US and southern Canada. A team of Canadian biologists used DNA fingerprinting to track the migration of 470 grizzlies near Canada’s Highway 3, a major east-to-west route through the Rocky Mountains and two adjoining ranges. The team obtained DNA from individual bears via hair samples snagged in barbed-wire strands set around smelly bait. Since bears from different populations carry a different mix of genetic types at 15 highly variable regions in the genome,