Understanding Horse Senses
A horse’s skull. To note: The delicate nasal bones, which many halters and bridles compress, causing pain. The teeth, starting with incisors at the front, then 4 canines (this may be a male), and finally the 3 premolars and 3 molars. Note that while the lower jaw is large, it is thin, and a bit can grind the soft gums or tongue into it. Note also the huge socket for the eye, the huge nasal cavity, and the relatively small brain case. A horse is better at smelling and seeing than it is at thinking.1
Horses and people sense the world very, very differently. Our interactions with horses will be much better when we realize these differences, and work with them.
When we sense the world, nerves of various sorts send information to the brain, which selectively interprets these signals and assembles a picture of the world for us. That picture is floated into consciousness piece-meal. A background sound can be effectively unheard until we choose to attend to it, when suddenly it can dominate the foreground of sounds we are hearing.
How we perceive reality has sometimes been called our “umwelt”. This combination of meaningful perceptual features of the world defines our reality. I cannot know your umwelt any more than you can know mine, but it is more likely that they are largely the same than it is that they are largely different. If you are blind or deaf, of course, then they are different.
A horse has an umwelt too. And it is likely very, very different than ours. Horses are awkward as lab animals for histological or neurophysiological research: they are big and expensive. But even if they were small and cheap, like white mice, research on perceptual capacities in non-humans is slow and difficult. So, unfortunately, there is much we don’t know about horses.
We should expect that a horse’s experiences of the world are very different than ours. We know that dogs can hear ultrasound — sounds higher than the range of human hearing — and that elephants can hear infrasound — sounds lower than the range of human hearing. We have learned that bees and birds and butterflies see ultraviolet light, and that a male silkworm can detect a female over 6 miles away. We know that birds can fly by the stars, and can sense magnetic fields. And so we have reason to suspect big differences between horse sense and human sense.
Much of our species’ early development was in the trees, in heavy vegetation. Horses developed on the plains, in open habitat. Humans ate fruit, and needed color vision to determine what was ripe. Horses ate grass, and didn’t need red at all. Humans hunted, and needed to be able to focus on selected prey. Horses were adept at running away from predators, but had to spot them first, somewhere on a 360 degree horizon. Our sensory systems evolved to give us what we needed, with few luxuries. So we would expect that the vision, hearing, and smell of humans and horses might greatly differ.
As we review the differences between humans and horses in vision, hearing, and smell, it will become more clear that horses and humans are from different planets.2
In this section on horse senses, each major sense is treated separately. But a horse is like us and all other animals, using senses in combination and coordination, not isolation. Some assembly required.
1 Image source: “Horse teeth”. Wikipedia. https://en.wikipedia.org/wiki/Horse_teeth
2 For more on this idea, see Saslow, Carol A. “Understanding the perceptual world of horses.” Applied Animal Behaviour Science 78, no. 2 (2002): 209-224.