The sound made by a male big brown bat as it zeroes in on a bug to eat is a sequence of chirps beyond the range of human ears. To another bat, the meaning is unmistakable: "Back off."
Scientists have identified a previously unknown call made by these bats — different from the sonarlike echolocation used for midair navigation and hunting — that tells another foraging bat to keep away from their prey.
The call is made exclusively by the males of this species for reasons that are not entirely clear. And the other foraging bats seem to honor the request.
The discovery indicates that acoustic communication in these flying mammals may be more sophisticated than previously thought and underscores the importance of vocal social communication for these nocturnal insect-eating animals.
"Bats may be avoiding aggressive interactions with the other bat," said University of Maryland biologist Genevieve Spanjer Wright, who led the study, published in the journal Current Biology.
"Chasing and even occasional physical contact have been observed in this species during foraging flight, so use of — and response to — social calls could be a way to limit the need for aggressive interactions or even injury to the responding bat," Wright added.
The big brown bat ranges from Canada to northern South America.
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