When A Drone Flies By, Does It Freak Bears Out?

If a UFO suddenly appeared in the sky outside your window right now, it’s likely your heart would start beating faster. Well, the same is true for bears, researchers now report. Except instead of UFOs, in this case they are actually unmanned aerial vehicles (UAVs).

UAVs, also known as drones, have become increasingly valuable to wildlife researchers, letting them observe animals, including endangered species, in their natural settings from long distances and over difficult terrain. It had looked like wild animals were taking these encounters in stride.

American black bears, for example, rarely seem to startle or run away when a UAV comes near. But this new study reveals that despite the bears’ calm demeanor when in the presence of UAVs, their heart rates soar, a sign of acute stress. Says Mark Ditmer of the University of Minnesota, St. Paul:

“Some of the spikes in the heart rate of the bears were far beyond what we expected. We had one bear increase her heart rate by approximately 400 percent–from 41 beats per minute to 162 beats per minute. Keep in mind this was the strongest response we saw, but it was shocking nonetheless.”

How did they figure that out?

The researchers fitted American black bears living wild in northwestern Minnesota with Iridium satellite GPS collars and cardiac biologgers. The collars sent the researchers an email with each bear’s location every 2 minutes while the biologgers captured every heartbeat. Then Ditmer and his colleagues programmed a UAV to fly to the bear’s most recent location.

All of the bears in the study responded to UAV flights with elevated heart rates. Fortunately, the bears recovered very quickly.

“UAVs hold tremendous potential for scientific research and as tools for conservation,” Ditmer says. “However, until we know which species are tolerant of UAVs, at what distance animals react to the presence of UAVs, and whether or not individuals can habituate to their presence, we need to exercise caution when using them around wildlife.”

These finding mean it will now become necessary to consider the additional stress on wildlife from UAV flights when developing regulations and best scientific practices.

UAVs are growing in popularity for many uses in addition to research, for example, discouraging poachers or tracking down wildlife for ecotourists. Currently, in many countries, few rules are in place to guide UAV use.

Ditmer et al.
Bears Show a Physiological but Limited Behavioral Response to Unmanned Aerial Vehicles.
Current Biology, August 2015 DOI: 10.1016/j.cub.2015.07.024

Photo: Jitze Couperus/flickr