Amazing stuff!
"A mother bat has one crucial challenge: find her own babies among hundreds of other bats in the colony. Making sure she cares for and nurses only her own offspring is important to ensuring their survival. Among Japanese house bats, mothers keep track of their pups using the babies' isolation calls.
To understand how these calls affect the mothers, the researchers monitored changes in the heart rates of mother bats presented with calls from their own babies and other bats' babies. ..."
From the abstract:
"Maternal care is essential for offspring survival in mammals, especially in colonial species where mothers must recognize their own pups.
In the Japanese house bat, Pipistrellus abramus, mothers identify their pups using acoustic cues, particularly isolation calls (ICs) produced by newborns.
However, the psycho-physiological mechanisms underlying such recognition remain largely unknown.
Here, we investigated maternal emotional responses to pup calls by measuring heart rate (HR) changes during controlled playback experiments.
We recorded ICs from 2-day-old pups and echolocation calls (ECs) from 30-day-old pups, then presented these sounds to mothers after the early nursing period.
HR significantly increased in response to calls from mothers’ own pups—both ICs and ECs—but not to calls from non-family pups.
Among all stimuli, ECs from their own older pups evoked the largest HR increase, indicating heightened physiological arousal and sustained maternal responsiveness despite developmental changes in call structure.
Unexpectedly, ECs from an unfamiliar adult also induced HR elevation, suggesting that elevated HR can also be triggered by other salient social cues. These findings demonstrate that P. abramus mothers exhibit enhanced physiological responsiveness to their own pups’ vocalizations, and that HR serves as a sensitive index for evaluating arousal levels and social auditory processing based on dynamic acoustic information.
Although HR alone cannot separate positive from negative emotional valence, these results highlight the utility of HR for monitoring physiological arousal associated with socially relevant acoustic stimuli in bats."
Mother bats’ hearts beat faster at the sound of their own babies’ cries (original news article) "To find their babies in large colonies, Japanese house bats listen out for the pups’ calls. Isolation calls warn a mother bat that her baby is lost and needs help, while unique identifiable features of these calls allow mother bats to be sure that they’re feeding and caring for their own offspring rather than someone else’s: house bats don’t provide any care to other colony members’ pups. A team of scientists studying how mother bats recognize their babies’ calls found that the mother bats’ heart rates speed up when they hear calls from their own pups, but not when they hear calls from other pups."
