Animals in the same circumstance of being a potential meal for some predator take the advantage of eavesdropping. Danger calls are understood as such by many animals who have no biological relation to the caller.
The converse is also true. Lack of alarm in animal community chit-chat indicates that no danger is apparent. “Eavesdropping on public information about safety is widespread and broad,” reported evolutionary zoologist Keith Tarvin. Squirrels, for instance, listen in on bird chatter to tell whether they can relax.
“Animals gather information from their environment using cues that may at first glance seem irrelevant,” said evolutionary ecologist Jakob Bro-Jorgensen. “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.”
Marie V. Lilly et al, “Eavesdropping grey squirrels infer safety from bird chatter,” PLoS One (4 September 2019).
James Gorman, “Squirrels relax when they hear birds relaxing,” The New York Times (4 September 2019).
Nicola Davis, “Squirrels listen to birds’ chitchat to gauge if trouble’s afoot – study,” The Guardian (4 September 2019).