Drones cause bears to suffer acute stress: UAV users urged to 'exercise caution' around wildlife

People using drones to explore wildlife may be doing more harm than good, especially when it comes to bears. The flying devices, also known as unmanned aerial vehicles (UAV), are likely to end up leading the animals to suffer from a bout of acute stress.

Research published in Current Biology says at first it appeared that bears were not disturbed by the introduction of drones to their lives as they remained calm and rarely ran away, American black bears in particular. But despite their apparent serene demeanour, their heart rates are sky high.

Mark Ditmer, of the University of Minnesota, St Paul, said: "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% – 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."

Ditmer and his team fitted wild American black bears in Minnesota with iridium satellite GPS collars and cardiac biologgers that let the researchers know the location of the bears at two-minute intervals and monitored their heartbeat. Drones were then sent to the area in which the bears were roaming.

The team noted only two bears showed any behavioural changes during 18 flights but saw that all consistently strong physiological responses with their heart rates rising when UAVs were about. However, the heart rates of the bears returned to normal soon after.

"Without the use of the biologger, we would have concluded that bears only occasionally respond to UAVs," Ditmer says. "UAVs hold tremendous potential for scientific research and as tools for conservation. 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."

The next stage in Ditmer and his team's research will be to work with captive bears to discover if they can get used to UAVs.