Page 112 - August 2022

EQUINE HEALTH
Hearing in Horses
HOW HORSES HEAR, HEARING LOSS, AND GENETIC DEAFNESS
Horse ears are sensitive and delicate, and well designed for excellent hearing. The horse in the wild depended on
keen eyesight, sense of smell, and good ears to detect danger in order to flee from predators before they got close enough to eat him. The funnel shape of the ear captures and conducts sound vibrations, and hairs on the inside keep dirt and insects from getting down into the ear. The ear canal at the base of the ear drops straight down about 2 inches, then turns sharply before reaching the eardrum where
by Heather Smith Thomas
sounds are transmitted to the inner structures of the ear that transforms vibrations into electrical signals for transport to the brain.
In all animals, the sense of hearing serves three major functions—to detect sounds, to pinpoint location of sound sources, and to provide information that enables the animal to recognize the identity of those sources.
Brian Timney, PhD (Professor emeritus, University of Western Ontario) says there is very little data on hearing in horses,
but there have been a few studies in
which sound detection and localization were examined, looking at how well the horse can tell where sound is coming from. “There’s also some data on auditory thresholds—the minimum amount of sound the horse hears, as a function of sound frequency,” he says.
An early study published in 1963, stated that horses could respond to certain sounds coming from a long way off. One of the first systematic attempts to assess hearing in horses was published in 1978, using behavioral clues
110 SPEEDHORSE August 2022