Get access to everything we publish when you sign up for Outside+.
Fly a drone near black bears, and they will likely just ignore the aerial invader. But they may be more stressed out by it than they appear, according to a new study.
Led by biologist Paul Ditmer, a team from the University of Minnesota fitted black bears in the northwestern portion of the state with GPS collars and biologgers, capable of measuring and recording the animals’ heart rates. They then programmed a UAV to buzz the bears, simulating the kind of flight that wildlife researchers might use to gather data.
The scientists found that the bears mostly outwardly ignored the drone: In only two instances did the animals change their behavior when the gizmo closed in. But their physiological responses told a different story. In a paper published in Current Biology, the team said that the bears’ heart rates consistently jumped in the presence of the drone.
“We had one bear increase her heart rate by approximately 400 percent—from 41 beats per minute to 162 beats per minute,” Ditmer told Phys.org. “Keep in mind this was the strongest response we saw, but it was shocking nonetheless.
While the team doesn’t say that their results should rule out unmanned aerial vehicles as a scientific tool, Ditmer says that scientists need to use caution when deploying them around wildlife until they better understand how the devices impact different species. In the meantime, he’s now conducting tests on bears in captivity to determine whether they can learn to better tolerate drones.