A mother bat's heart beats faster for her own baby's cry — and only hers

A mother's heart gives her away. Researchers studying Japanese house bats found that a mother's heart rate rises much more strongly when she hears her own pup's calls than when she hears another family's pup — a quiet, measurable sign of the bond between mother and baby, written in heartbeats. The study, published in Frontiers in Ethology, is a small window into how deeply recognition runs in the animal world: long before a pup can fly, its mother already knows its voice by heart.