A remnant herd of caribou in eastern Canada faces a grave threat from a surprising source: backcountry skiers. The endangered woodland caribou (Rangifer tarandus caribou) live atop the snowy mountains of Gaspésie National Park, near the mouth of the St. Lawrence River in southern Quebec province in Canada. Over the past 30 years, this population has shrunk by 63%—to just about 70 animals—as a result of increased predation by coyotes and black bears, as well as competition for food with growing numbers of moose and deer. Hikers and skiers are allowed on most of the mountains in Gaspésie National Park. But the resident caribou appear unwilling to share their slopes with tourists: The presence of just six skiers at the summit was enough to send the animals scurrying down to lower elevations, where they face a far greater risk of predation by coyotes, researchers report in the current issue of Biological Conservation. Ecologists outfitted 43 of the caribou with GPS collars and tracked their movements for 2 years, finding that they can spend up to 5 days on lower slopes after getting spooked by skiers. Although tourist use of the park is already limited, the authors are urging park managers to impose additional restrictions on high-altitude skiing and hiking. Without stronger measures, the team predicts that the herd could vanish within 2 decades.