A new study published in the journal Current Biology shows that, unsurprisingly, black bears in Minnesota freak out when you fly unmanned aerial vehicles near them. Four bears, already hooked up with GPS and implanted heart sensors for a different study, were monitored as small drones took flight overhead on 18 separate occasions. The bears’ heart rates went wild whenever a drone was near; one was so scared its heart rate increased 400 percent. The heart monitor was often the only way to gauge the bears’ reactions to the drones, as they mostly pretended like it wasn’t even a big deal — except for the one bear in the cornfield that ran away when the drone came, gave up after like 15 feet, and then just stared at the weird mechanical bird, perhaps trying to decide if it tasted good enough to pursue. The study’s author told NPR he wasn’t sure if wildlife was going to get used to the buzz of drones. If not, it seems probable that the next installment of Planet Earth will need to be framed as an environmental horror film.