The Hearing Ability of Horses

In the course of comparative studies of Testing mammalian hearing, we have recently begun to examine the hearing abilities of horses.' There are several standard behavioral proOur choice of horses as subjects for auditory cedures currently used to determine the research was based on theoretical considerhearing abilities of mammals.' The proceations related to their size as well as to the dure which we used here is known as a "go1 fact that the auditory abilities of Perissono-go" procedure in which an animal is redactyls were previously unknown. Yet in adwarded for making aspecific response whendition to its theoretical importance, a knowever it hears a sound. In our test, water was ledge of the hearing abilities of horses has used as the reward and the horses were recertain practical value. For example, the quired to work each day to obtain their water. ability to specify the range of sounds which Three horses from 18 to 20 months old were horses can hear is useful in identifying those tested: a Quarter horse gelding, an Appasounds which a horse might respond to or be loosa mare and a Welsh pony x Quarter disturbed by. Furthermore, such information horsegelding. provides a starting point for any investigaSpecifically, a thirsty animal was led into tion of deafness in horses. an indoor stall and trained to place its nose The purpose of this article is to describe on an "observing" plate located in front of a the auditory sensit~vity of the horse and the loudspeaker (Fig. 1). A Ssecond pulsing tone methods used to determine it. In addition, was then presented at random intervals from the hearing ability of the horse is discussed 3 to 27 seconds apart. Once the tone ocin terms of how it compares with that of curred, the horse was required to break conother mammals as well as its relevance to the tact with the observing plate and touch a understanding of equine behavior. "reporting" plate within 3 seconds after the