Overview
- The peer-reviewed study, published Feb. 23 in Current Biology, was led by Elodie Mandel-Briefer of the University of Copenhagen.
- The high-pitched element is a whistle generated in the voice box when tissue above the vocal cords narrows, while the low pitch comes from vibrating vocal folds.
- Ex vivo experiments showed the high tone rose in helium whereas the low tone stayed constant, indicating two distinct sound-generation mechanisms.
- Independent experts said the data demonstrate true biphonation in horses, a rare trait in mammals previously documented mainly in small rodents.
- Authors propose the two-tone call may support long-distance contact or encode emotional information, but these functions remain unconfirmed.