Quick, drive away—you're making the elk nervous. Elk in Alberta become more fearful when people are around because they perceive them as predators, new research suggests. Researchers teased out these human-wildlife dynamics by observing elk in Alberta, Canada, over the course of a year. Tracking 424 herds and 870 individuals on public land, private land, and protected land, the scientists watched—from a safe distance—as the animals went about their lives. They recorded the elk's behavior, such as feeding, grooming, and resting. Humans accounted for the greatest degree of disturbance to the animals, the scientists found—even more so than the elk's natural predators, which include wolves, cougars, and grizzly bears. When elk encountered humans, especially on public lands where hunting and all-terrain vehicle use were permitted, the animals snapped into vigilance mode, scanning their surroundings for danger. Just one car passing every 2 hours was enough to induce this behavior, which detracts from feeding time and can in turn leave females in a less healthy state for bearing young. "Humans are playing the same role as a natural predator, but probably at even higher levels," says Simone Ciuti, a behavioral ecologist at the University of Alberta and lead author of the PLOS ONE study describing the elk observations. "As a consequence of this stress, females may have lower reproductive success," he says. Ciuti and his colleagues plan to investigate how different human activities, such as hunting and hiking, impact the animals' behavior. They also plan to test whether their results apply to, and perhaps explain, declines in sensitive species like caribou.
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