Mother Japanese house bats’ heart rates rise at their own pups’ calls, study finds
An experiment with four mothers found different heart-rate responses to calls from their own pups and unrelated pups, but the measurements cannot reveal what the bats felt.
Mother Japanese house bats in a Japanese experiment showed faster heart rates when they heard recordings of their own pups, but not unrelated pups, according to a study published on October 23 in Frontiers in Ethology. The finding offers a physiological measure of how mothers respond to offspring calls in a colony where identifying their own young matters for care and nursing.
How researchers tested the mothers’ responses
The researchers studied four mother bats, each with a litter of three pups. They recorded the pups’ isolation calls when the young were two days old and later recorded their echolocation calls. About 40 days after the births, they separated the mothers from their offspring, played recordings of pup calls and monitored the mothers’ heart rates with ECG equipment. The playback also included the call of an unfamiliar adult male bat.
Calls from a mother’s own pups increased her heart rate, while calls from other mothers’ pups did not. The strongest increases came in response to recordings of older pups that had become independent, Popular Science reported. The researchers suggested that greater familiarity with those more recent calls might explain the difference, but that explanation has not been established.
What the heart-rate changes can show
The unfamiliar adult male’s call also produced a strong heart-rate response. That result matters when interpreting the pup-call finding: a faster heartbeat shows that a bat reacted, but it does not identify whether the response was maternal motivation, stress or alarm. Lead author Yoshino-Hashizawa said measuring overall heart rate gauges the intensity of physiological arousal without distinguishing positive from negative emotion.
Yoshino-Hashizawa said future work would need heart-rate variability analysis to better examine how the bats’ autonomic nervous systems respond to the calls. The experiment’s four mothers also make its finding specific to this small group of Japanese house bats; it does not establish that other bat species respond in the same way.
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Sources and context
- Mother bats' hearts beat faster at the sound of their own babies' criesPhys.org, reporting provided by Frontiers
- Bat mothers' hearts beat faster when they hear their pupsPopular Science
- Mother bats’ hearts beat faster at the sound of their own babies’ criesEurekAlert! (syndicated from Phys.org; underlying report provided by Frontiers)
AI-assisted article checked against the listed sources. NewsJaws did not conduct interviews or attend the reported events.