Grizzly bears have keen noses – far keener, in fact, than a bloodhound’s. The big bruins literally sniff their way through life, relying on their sense of smell to find distant mates and remote food sources. So, to count the number of grizzlies in the Cabinet-Yaak ecosystem, researchers turned to a distilled essence of fish guts and cow’s blood. The liquid is sprinkled on logs surrounded by barbed wire. When the bears crawl over the wire to investigate the scent, they unwittingly leave DNA behind in clumps of hair, which will be analyzed to identify individual bears.