For centuries, the science behind the horse’s whinny – a sound as iconic to the animal as its gallop – has remained an intriguing mystery. Now, a new study published in Current Biology has uncovered a surprising mechanism: horses actually whistle to create the high-pitched component of their signature call.
The Dual Nature of a Whinny
The whinny isn’t a single sound but a complex blend of high and low frequencies. Researchers previously understood the low-pitched rumble, which is generated like human speech through vibrating tissues in the voice box. The high-pitched squeal, however, defied explanation. Larger animals typically produce lower tones; yet, horses manage to create this unusual combination.
To solve the puzzle, scientists used miniature cameras inserted through horses’ nostrils to film the vocal process in action. They also conducted detailed scans and experiments with isolated horse voice boxes. The results confirmed something unexpected: the high-pitched tone is produced by whistling within the voice box itself.
How Horses Whistle
Unlike humans, who whistle with their mouths, horses create the sound by vibrating tissues in their voice box while simultaneously contracting a nearby area to create a small opening. This allows air to escape, generating the distinctive whistle. Only a handful of small rodents, like rats and mice, share this vocal technique among mammals. Horses are the first large animal discovered to use it.
“I’d never imagined that there was a whistling component. It’s really interesting, and I can hear that now,” said Jenifer Nadeau, a horse behavior specialist at the University of Connecticut, who was not involved in the study.
Evolution and Communication
The origin of this two-toned call remains unclear. Some wild horse populations – like the Przewalski’s horse – and even elks can produce similar sounds, while other horse relatives, such as donkeys and zebras, cannot. This suggests that the ability evolved in specific lineages.
The dual nature of the whinny may allow horses to communicate more complex messages. The different frequencies could convey a wider range of emotions during social interactions. Study author Elodie Mandel-Briefer, from the University of Copenhagen, explains that horses may be able to “express emotions in these two dimensions.”
The discovery not only deepens our understanding of equine vocalizations but also highlights how little we still know about the complexities of animal communication. The whinny is more than just a call; it’s a biological marvel.
