I just got back from a camping trip in one of Ontario's provincial parks, where I saw at least one raccoon (there were probably more) brazenly approach our campsite, looking for food. We tend to think of raccoons, badgers, and other smaller carnivores as completely fearless of humans, but it seems that's not the case. In fact, they may be so frightened of human "super predators" that they avoid a meal just because of the sound of our voice.
Fear can have all sorts of significant effects on an ecosystem. When animals are afraid, they may have fewer babies or feed less because they're constantly on the alert for a scary predator. In that way, fear can produce effects that echo through an entire food chain. That's why researchers say it's important to understand what makes animals afraid.
Turns out that, to European badgers in the forests outside of Oxford in the UK, humans are on top of the list. That's according to Liana Zanette and Michael Clinchy, two researchers at Western University in London Ontario, who've got a new study in Behavioral Ecology in which they played recordings for European badgers—the sounds of growling bears, dogs, wolves, and humans talking—to see which terrified the poor badgers the most.
Hearing human sounds caused most badgers to completely stop feeding, even though the researchers had put out tempting buckets of peanuts for them. The brave animals who did come out in search of a snack spent less time eating, and more time with their heads up looking around, scouting for danger that could be approaching. Although they were somewhat afraid of bears and dogs, humans produced the strongest effect.
And the humans weren't even yelling or making threatening noises, necessarily. Among the recordings that were played from speakers positioned near the food, starting at sunset in two-hour stretches, "there was a clip from Quirks and Quarks on there," Zanette told me, referencing CBC Radio's long-running science show, "some BBC documentaries," and a reading of The Wind in the Willows, a children's story about badgers.
The European badgers were terrified.
Badgers in that area have long been hunted by dogs and humans, Zanette said. Bears and wolves, on the other hand, have been extinct there for hundreds of years, so maybe it makes sense that at this point the badgers would fear us more than their traditional predators.
"We wanted to see the extent to which they were afraid of their current predators, humans and dogs, versus extinct predators, bears and wolves," she explained.
In an earlier study, in BC's Gulf Islands, Zanette and other collaborators found that raccoons were frightened by the sound of barking dogs, which makes sense: The worst they typically have to contend with is humans and their dogs. (The researchers also played barking seals as one of the controls.)
In that raccoon study, impacts were seen throughout the food chain. After the barking went on for a month, species that the BC raccoons typically feed on, like red rock crab, were exploding in numbers, Zanette said. "There were changes in tiers all down the food chain."
Bears and wolves are scary, but there's no doubt that humans have wiped out more badgers than probably all the bears and wolves, combined. (And that's not even to mention the indirect effects of climate change, urbanization, the list goes on.)
Understanding the implications of all this, and the fear we strike into the hearts of these little creatures, is important, Zanette told me. It's producing effects we still barely understand.