Horses are one of only a small number of animals that can make biphonic sounds, new research has found.
The study, published in the journal Current Biology, explored the horse’s whinny found that the noise is made from two sounds at once.
The first is lower-pitched and is made when air passes through bands in their larynx, which is similar to how humans speak, while the second is a higher-pitched sound.
While the former has been readily attributed to vibrations of the larynx, the processes underlying the higher frequency ‘whistle’ were previously unknown.
By scoping 10 living stallions, as well as scanning isolated larynxes of dead horses obtained from French butchers, the team established that the whistle sound was made by forcing air through the cartilage of the larynx.
“To our knowledge, this study provides the first demonstration of simultaneous aerodynamic whistles and vocal fold vibration during biphonation in any species,” said the research team.
“It also provides the first clear experimental evidence of a laryngeal whistle in a non-rodent mammal.”
Horses are among a small number of animals who can make two sounds at once, including some bird species and human beatboxers.
The researchers added that the ability to make biphonic sounds may allow horses to convey complex messages to each other.
The full study can be found here.
Lead image by Shutterstock
