Study Reveals Horses Whinny via Vibration and Whistle

Scientists have uncovered the mechanism behind the distinctive whinny of horses, revealing that the animals produce two simultaneous frequencies in their larynx, one through vocal cord vibration and the other through a form of whistling. The discovery, detailed in a study published Monday in the journal Current Biology, explains a long-standing puzzle in animal vocalization and highlights horses' unique ability among large mammals to combine these sounds.

Horses use whinnies, also known as neighs, to locate new companions, greet familiar ones, or express excitement during activities like feeding. The sound blends a low-pitched grunt with a high-pitched squeal, creating a biphonated call that has puzzled researchers for years. While the low-frequency component, around 200 hertz, arises from air vibrating the vocal folds in the larynx much like human speech or singing, the high-frequency element exceeding 1,000 hertz has been harder to explain. Larger animals typically generate lower sounds due to their bigger vocal structures, making the high pitch in horses an anomaly.

To investigate, a team led by Élodie Briefer, an associate professor in the department of ecology and evolution...