If a person saw an unidentified flying object suddenly shoot past overhead, odds are that his or her heart would begin to beat more rapidly. Now, new research led by experts at the University of Minnesota, St. Paul has found that the same thing happens to bears.
Writing in the August 13 edition of the journal Current Biology, Dr. Mark Ditmer of the UM Department of Fisheries, Wildlife and Conservation Biology and his colleagues explained that the unmanned aerial vehicles (UAVs) used by wildlife researchers to observe creatures in their natural settings cause the heart rates of American black bears to soar.
The UAVs, which help experts monitor species (particularly endangered ones), do not appear to have any effect on the bears’ demeanor, and the creatures rarely run away or seem startled. Yet the new research found that the heart rate of bears subjected to drone flybys can rise by as much as 400 percent.
“Going in, we had four hypotheses: 1) no strong behavioral or physiological response 2) a behavioral only, 3) physiological only and 4) both a behavioral and physiological,” Dr. Ditmer explained to redOrbit via email. “Given that bears in this area are routinely exposed to human sights, sounds and smells in forms of farming equipment, agricultural areas and vehicle traffic, we expected the bears to mostly take the UAV flights in stride.”
“Therefore I hypothesized that we might see a slight rise in heart rate but I thought we would mostly just see a behavioral response,” he added. “The magnitude of some of the heart rate spikes were shocking. An adult female with cubs’ heart rate was 41 beats per minute prior to the unmanned aerial vehicle flight but it spiked to over 160 beats per minute during the flight.”
Should the use of conservation drones be discontinued?
As part of their research, Dr. Ditmer and his fellow investigators placed Iridium satellite GPS collars and cardiac biologgers on free-roaming American black bears living in the northwestern part of Minnesota. These collars sent the team an email with the location of the bears every two minutes, while the biologgers provided a consistent record of their heartbeats.
Next, they programmed a UAV to fly to the bear’s most recent location, and monitored the data to see how the bears reacted to the five minute long drone flights. Over the course of 18 flights conducted in the vicinity of four different bears, only twice did the animals show any significant change in their behaviors. However, each of the bears had strong physiological responses in the form of elevated heart rates, from which they recovered quickly.
Dr. Ditmer’s team said that it will now be necessary to consider the additional stress on wildlife caused by UAV flights when developing regulations governing the drones and when deciding the best scientific practices for the flying machines. In addition to being a valuable research tool, the UAV has been used to discourage poaching and to locate animals for ecotourism.
“By no means are we advocating against the use of UAVs, especially for research or conservation,” Dr. Ditmer said. “UAV’s hold tremendous potential for scientific research and as tools for conservation. Our research is a cautionary tale to let people know we need to understand the trade-offs of UAV use. If using a UAV to keep poachers away causes some stress in an individual I would certainly say it is very worthwhile.”
“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 remember that their presence may have a negative impact that isn’t always obvious,” he added.