Drones stress bears out

Elena Scotti/FUSION

Scientists and tech-savvy conservationists are starting to fly drones in woods and national parks to study and protect, respectively, animals in the wild. But they may be unwittingly doing harm to critters according to new research that confirms the obvious: weird, buzzing things in the air are stressful to those below.

Brave scientists from the University of Minnesota, St. Paul outfitted four free-roaming black bears with GPS collars and heart rate monitors so that they could study the effect that drones, a.k.a. unmanned aerial vehicles (UAVs), had on them. As the cyborg bears tromped through the woods in northwest Minnesota, their pulse and location info was beamed back to the scientists every two minutes. The team then programmed a small 3D Robotics quadcopter to fly to the bear's location and loiter for about five minutes roughly 20 meters above their heads.

Jessie Tanner

The researchers buzzed the bears—two adult females with cubs, a 1-year-old male, and a hibernating female—18 times in total, and tracked their reactions by the effect on their heart rates and movements.

Graphs showing a bears movement and heart rate. The grey bar depicts time when drone flew overhead.
Current Biology

"All bears, including an individual denned for hibernation, responded to [drone] flights with elevated heart rates, rising as much as 123 beats per minute above the pre-flight baseline," the authors write in a study published Wednesday in the journal Current Biology, which describes the work. (The researchers weren't able to collect data from the cubs because they didn't have the needed sensors.)


They expected that perhaps the bears would move around more, as they (presumably) tried to get away from the drone. But that wasn't the case. According to the researchers, an increased heart rate was the only discernible sign of stress the animals showed.

After the drone went away, their heart rates went back down. Humans living near airports seem to react similarly. Recent studies have shown that noise from airplanes flying overhead can also lead to increases in heart rate and blood pressure.


The team's next experiments will test whether animals learn to ignore drones over time. Which sounds a lot like a plan to torture animals for longer periods of time.

The study is definitely small in scope—after all, they only tested four bears, only three of which were moving around, but Mark Dittmer, the study's lead author, cautions:

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.


Previous studies on birds, like ducks, wild flamingos and common greenshanks, for instance, reported that drones didn't have any adverse effects on animals, but they only measured behaviors, like flying away or how much they moved their heads. They didn't look at heart rate, and as the authors of the Current Biology study note, the effects on animals may be imperceptible unless we use the right sensors to measure them.

The findings of this study are something to keep in mind as we move toward drone-assisted research on animals like endangered Hawaiian monk sealsospreys, and other types of wildlife.


We've spent a lot of time and energy in studying robot interactions with humans, and we should do the same with animals, since they're not just approaching animals from above. According to Audubon Magazine, "researchers are attaching arms that grab objects in midair like an eagle, and kestrel-like legs that allow drones to perch."

As we're doing this, we should ask ourselves: Are we changing the very thing we're trying to study when using drones? Are we doing more harm than good by using new technologies to study them?


Bears aren't the only animals to be freaked out by drones. Pets also seem freaked out by robolife. As my colleague Kevin Roose put it: "Some dogs see drones as terrifying killer robots." He predicted an animal vs. machine war would break out, and if these videos of a ram ramming a drone and an eagle taking another one down are an indication, he's right.

It's worth it to keep investigating robot-animal relationships. After all, as robots become more of a part of our daily lives, we're not the only ones they'll have to reckon with.

Daniela Hernandez is a senior writer at Fusion. She likes science, robots, pugs, and coffee.

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