In a new study out of Oberlin College, researchers found that "eastern gray squirrels eavesdrop on non-alarm auditory cues as indicators of safety"

By Jen Juneau
September 05, 2019 09:20 AM

We might be able to learn a thing or two from squirrel instincts.

Researchers at Oberlin College — biologist Keith A. Tarvin and two of his students, Marie V. Lilly and Emma C. Lucore — published a study on Wednesday that came about after they observed the behavior of eastern gray squirrels when exposed to hawk sounds versus silence/ambient sounds and “bird chatter.”

Impressively, “Squirrels exposed to the chatter treatment engaged in significantly lower levels of vigilance behavior (i.e., standing, freezing, fleeing, looking up) and the decay in vigilance behaviors was more rapid than in squirrels exposed to the ambient noise treatment” after they had first been exposed to the hawk, a.k.a. predatory sounds.

“These findings suggest that eastern gray squirrels eavesdrop on non-alarm auditory cues as indicators of safety and adjust their vigilance level in accordance with the vigilance level of other species that share the same predators,” the study continued.

Matt Cardy / Stringer

Lilly — who helped design the study alongside Lucore — spoke to both The New York Times and NPR about the practical parts of the experiment, which saw her bicycling around Oberlin, Ohio, in January, looking for squirrels in the freezing weather.

“It definitely did look very ridiculous,” she told NPR, explaining that she brought the audio equipment along with her inside of emptied cat-litter containers. “I put those on my bicycle, and basically rode around town looking for squirrels.”

Lilly observed from her hiding places — often behind bushes — how long a squirrel exposed to each audio sample — hawk cry, silence or bird chatter — would engage in behavior that suggested “vigilance” (e.g., freezing, running away) versus a more relaxed nature (e.g., foraging, resting).

“In the field, I couldn’t tell if their vigilance level was going down or not because I was just recording their raw behavior,” she told NPR.

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But once the team analyzed the data (which Lilly gathered on an app created by a friend in computer science, NPR reported), it was clear that the critters relaxed more quickly when exposed to the bird chatter, “suggesting squirrels use information contained in bird chatter as a cue of safety,” the study reads.

Speaking with The Guardian, U.K.-based evolutionary ecologist Dr. Jakob Bro-Jorgensen (who was not involved in the research) noted that the study “calls attention to how animals can gather information from their environment by using cues that may at first glance seem irrelevant.”

“And it makes you wonder how the more and more pervasive impact of human activities on natural soundscapes may compromise survival of wildlife in ways we haven’t thought of,” he added.

Despite the study’s illuminating properties in regards to squirrel behavior, in her interview with the Times, Lilly also recognized that they “can’t know the impact of the sounds that we’re creating unless we know more about the sound information that’s part of the ecosystem.”