Bat signals

Abstract

Cave-dwelling bat species rely on echolocation to perceive their environment, but also experience high levels of acoustic interference from conspecific calls when flying at the same time (especially when emerging from the cave). Writing in Proceedings of the National Academy of Sciences of the USA, Goldshtein et al. explore how greater mouse-tailed bats (Rhinopoma microphyllum) cope with acoustic sensory overload, sometimes called the ‘cocktail party nightmare’. By combining high-resolution GPS tracking with individual-level acoustic data collected via miniature onboard microphones, they show that bats leaving their cave on collective foraging expeditions experience high levels of acoustic masking (weak echoes from nearby bats that are not detected). This occurs especially at the mouth of the cave, when thousands of individuals emerge within the space of a minute and the risk of collisions between individuals is high. However, the probability of masking decreased rapidly 25 m beyond the cave entrance, as does the proportion of echo-jamming by conspecifics (calls that overlap with echoes, but are louder). As a result, groups are able to still maintain collective movement over several kilometres, while avoiding collisions. Goldshtein et al. support these findings using a biologically plausible sensorimotor model that predicts a rapid decrease in bat collision rate beyond the cave entrance, as the probability of detecting echoes from conspecifics increases alongside reductions in the proportion of acoustic masking and echo-jamming.

Original reference: Proc. Natl Acad. Sci. USA 122, e2407810122 (2025)