Ever wondered why your horse suddenly stops or spins around out hacking, or snorts and spooks unexpectedly — usually when there is nothing there? In fact there is, but as the horse’s range of hearing eclipses a rider’s, you are unaware of what they have heard. Although small, the ears are one of a horse’s greatest assets, and it is important to understand how they work
1 Horses can detect sounds as far as 4km away.
2 The ability to hear higher frequencies means horses can detect the ultrasonic shriek of a bat, which is inaudible to a person’s ear. That is why a horse often reacts to something that the rider is unaware of.
3 Horses can detect low-frequency sounds while grazing, via vibrations transmitted through the ground that he picks up with his teeth. The vibrations are conveyed to the middle ear through the jawbone. Hooves also pick up on these vibrations, thus warning of possible predators.
4 The conical shape of the outer ear — similar to an old-fashioned gramophone speaker — captures even the softest sounds.
5 This shape shields the sound the horse is trying to focus on, thus fading out other noises around him.
6 Healthy, young people can hear sounds from 20 hertz up to 20 kilohertz, and are most sensitive to sound between one and three hertz.
7 A horse’s range is far wider — from 14 hertz up to 35 kilohertz, another two-thirds of an octave.
8 Between one and 16 kilohertz is the horse’s best frequency of hearing.
9 There are 10 muscles in a horse’s ear — compared to three in a human’s — which control movement. That is why a horse can turn each ear in a separate direction to listen and communicate.
10 After the ear tells a horse which direction to look in, his almost 360-degree field of vision determines the exact location of the sound.
11 If the source of sound is identified as non-threatening, the horse will usually remain calm. But horses are prey animals and if it is considered threatening — or he cannot see the source at all — he will want to run in the opposite direction.
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