The echolocation calls of bats are mainly used for navigation and foraging; however, they may also contain social information about the emitter and facilitate social interactions. In this study, we recorded the echolocation calls of greater horseshoe bats (Rhinolophus ferrumequinum) and analyzed the acoustic parameter differences between the sexes and among individuals. Then, we performed habituation-discrimination playback experiments to test whether greater horseshoe bats could recognize the sex and individual identity of conspecifics from their echolocation calls. The results showed that there were significant differences in the echolocation call parameters between sexes and among individuals. When we switched playback files from a habituated stimuli to a dishabituated stimuli, the tested bats exhibited obvious behavioral responses, including nodding, ear or body movement, and echolocation emission. The results showed that R. ferrumequinum can recognize the sex and individual identity of conspecifics from their echolocation calls alone, which indicates that the echolocation calls of R. ferrumequinum may have potential communication functions. The results of this study improve our understanding of the communication function of the echolocation calls of bats.

In many vertebrates, vocal communication is crucial in parent–offspring interactions, and parents are often able to discriminate between the calls of their own and others' offspring. There are many reports on the unidirectional recognition of isolation calls of pups by maternal bats, but few studies on the ability of bat pups to recognize maternal acoustic signals. In this study, we investigated whether the echolocation pulses of female Asian particolored bats (Vespertilio sinensis) and isolation calls of pups differ statistically among individuals. We used two‐choice playback experiments to test whether the mothers and pups of V. sinensis can recognize each other by acoustic signals. Both the echolocation pulses of mother bats and the isolation calls of pups contained sufficient individual characteristics. Playback experiments showed that mothers were able to recognize isolation calls of pups, and most pups greater than 12 days old were able to distinguish echolocation pulses of their own mother from those of other mothers. This is the first use of two‐choice acoustic signal playback experiments to confirm that pups can recognize their mothers by echolocation calls. The results provide behavioral evidence for bidirectional recognition of acoustic signals between mothers and infants in frequency‐modulated type bats.

Vocal signals are the primary medium of intraspecific communication in bats, yet the encoding features and recognition mechanisms of distress calls remain largely unclear. This study aimed to examine sex, age, and individual signatures in noise burst to downward frequency modulation (NB-DFM) distress calls of the Rhinolophus ferrumequinum and verify conspecific recognition ability. We recorded NB-DFM calls from 20 adult and 9 subadult bats in Jilin Province, extracted 18 acoustic parameters, built classification models with support vector machines (SVMs), evaluated feature importance using random forest, and performed habituation-dishabituation playback experiments. SVM yielded classification accuracies of 67%, 89%, and 88% for sex, age, and individual identity, respectively, all significantly above chance levels. Call duration, central minimum frequency, and root mean square (RMS) were the most diagnostic parameters, and key acoustic variables differed significantly among classification levels. Playback tests elicited distinct behavioral responses to calls of different sexes, ages, and individuals, confirming discrimination ability. These findings reveal individual, age, and sex specific acoustic markers in bat distress calls, support the utility of machine learning for bioacoustic classification, and provide empirical insight into stress related acoustic communication in nocturnal mammals.

Vocal signals are the primary medium of intraspecific communication in bats, yet the encoding features and recognition mechanisms of distress calls remain largely unclear. This study aimed to examine sex, age, and individual signatures in noise burst to downward-frequency modulation (NB-DFM) distress calls of the Rhinolophus nippon and verify conspecific recognition ability. We recorded NB-DFM calls from 20 adult and 9 subadult bats in Jilin Province, extracted 18 acoustic parameters, built classification models with support vector machines (SVMs), evaluated feature importance using random forest, and performed habituation–dishabituation playback experiments. SVM yielded classification accuracies of 67%, 89%, and 88% for sex, age, and individual identity, respectively, all significantly above chance levels. Call duration, central minimum frequency, and root mean square (RMS) were the most diagnostic parameters, and key acoustic variables differed significantly among classification levels. Playback tests elicited distinct behavioral responses to calls of different sexes, ages, and individuals, confirming discrimination ability. These findings reveal individual, age, and sex specific acoustic markers in bat distress calls, support the utility of machine learning for bioacoustic classification, and provide empirical insight into stress-related acoustic communication in nocturnal mammals.