Mothers respond to biological pup calls with heart rate changes in Japanese house bats, Pipistrellus abramus

Maternal care is essential for offspring survival in mammals, especially in colonial species where mothers must recognize their own young among many. In the Japanese house bat, Pipistrellus abramus , mothers identify their pups using acoustic cues, particularly isolation calls (ICs) produced by newborns. However, little is known about the physiological responses underlying maternal recognition. Here, we investigated emotional responses of mother bats to pup calls by measuring heart rate (HR) changes during a controlled playback experiment. We recorded ICs from 2-day-old pups and echolocation calls (ECs) from 30-day-old pups, then presented these sounds to mothers after pup independence. HR significantly increased in response to their own pups’ calls, both ICs and ECs, while calls from non-family pups did not elicit significant changes. Among these, ECs from their own older pups evoked the largest average HR increase, suggesting sustained maternal responsiveness despite developmental changes in call structure. Additionally, unfamiliar adult calls induced HR elevation, possibly reflecting general social arousal. These findings indicate that P. abramus mothers exhibit selective physiological arousal to their own pups’ calls, with HR serving as a sensitive marker of maternal recognition and motivation based on dynamic acoustic information.