Fuzz: When Nature Breaks the Law

by Mary Roach

Adult black bears rarely stay put where they’re released. They have made their way home in journeys as lengthy as 142 miles—in one case including a 6-mile ocean swim. It is a remarkable achievement given that, unlike migrating birds, they can’t rely on internal magneto-gadgetry to help them navigate. Whether they are picking up sensory cues—the smell of the ocean, say, or the sound of an airport—or just trying out different directions until something feels familiar, is not known, but they are motivated and they are good at it. In a 2014 study, sixty-six conflict bears were radio-collared and translocated by Colorado Parks and Wildlife. Thirty-three percent of the adults made their way back to the spot where they’d been captured, and none of the subadult bears did. Those read as fairly optimistic statistics; however, if you define success not as the failure to return but rather as surviving a year in the new home, the picture is less rosy. Translocated bears often wander into a new town close to where they’ve been released and start getting into the same kind of trouble. More than 40 percent of translocated bears in Yellowstone National Park and 66 percent in Montana were involved in another “nuisance event” within two years. Yosemite rangers tried translocating the bears that were breaking into cars, moving them to the other side of the park. The result: car break-ins on the other side of the park.