Drones are becoming increasingly popular for use in many different ways. Unmanned aerial vehicles (UAVs) as they’re also called have become very effective in the field of science, especially in biological and environmental sciences to passively study animals. Use of UAVs has been helpful in studying animals in the wild and from a distance.
Until recently, it was thought that use of these vehicles didn’t affect animals in any way but a recent study has shown this may not be the case. Use of UAVs appears to be having a negative effect on bears when they pass overhead. A spike in heart rate, which is associated with acute stress, has been observed in bears in the presence of drones.
The team conducting the study fitted American black bears in Minnesota with GPS collars and biologgers. The GPS collars gave researchers the location of bears while biologgers tracked their heart rate. Using the GPS location of the bears, a UAV would be flown over the bear and its heart rate would be captured by the biologger. In the study, 4 individual bears were used for a total of 18 flyovers. Two of the bears were females with cubs, one was a female who had entered hibernation 2 days before the first flyover and the fourth was a young male.
The team found a large spike in heart rate in the bears in every flyover with the drone. The largest observed increase in heart rate was an increase of 123 beats per minute, which is a very large increase. This occurred in one of the female bears with cubs. The largest increase observed in the hibernating female was 56 beats per minute and 47 beats per minute in the young male. They also found that the maximum heart rate in the collared bears was higher on days when a flyover occurred than on days without one.
The highest observed heart rate was seen in female bears with cubs while there was less of an effect on the male bear studied. The heart rate of the bears slowed fairly quickly after the flyover occurred so this was good news. The flyovers didn’t appear to have any lasting effects on the bears.
The largest spikes seen in the bears occurred when they were startled by the drones. This occurred on windy days when, presumably, the bears couldn’t hear the drones coming and saw them just as they were passing over.
The researchers didn’t notice and change in behavior other than slowing down movement rate unlike in some other species. According to the study, flybys of aircraft can cause aggressive responses in some animals and it is clear that the same may be happening as a result of drones.
This study may have implications in the manufacture of drones in an effort to stop an increase in stress levels among animals. Nevertheless, drones are becoming an important part in the study of animals but scientists are beginning to acknowledge that they need to be careful when using drones.
The team, lead by Mark Ditmer of the University of Minnesota, St. Paul, is going to continue to explore the effects of UAVs on other species. The study was published in the journal Current Biology.