Written By: Holle Abee
In order to fully understand a horse, it’s important to understand his physiology, or his internal workings. Basic knowledge of how the horse’s body works will explain much of his behavior. One of the most revealing aspects of equine physiology is eyesight and its affects on how the animal reacts to certain situations.
Horses see the world much differently than humans do. The horse chiefly uses monocular vision, like most other prey animals. In other words, his eyes are on the side of his head, and each eye can see separately. Horses and their ancestors were hunted for millions of years, by large predators and by man. Their physiology adapted accordingly in order to survive. They see less detail than humans do, but they have a much wider range of vision. Their eyesight is extremely sensitive to movement, which was necessary to see approaching predators.
Because of his “prey vision,” he has difficulty judging depth and distance, unlike predatory animals that generally have both eyes in the front of the head: think lion, tiger, wolf, and human. This is the reason horses often balk when crossing ditches or depressions in the ground. They simply cannot judge them accurately. The fact that a horse cannot see his own front legs or chest doesn’t help any, either.
Horses are also able to employ the use of binocular vision, like humans do, to focus both eyes on the same object. A problem often arises when they switch from monocular vision to binocular vision. When they make the switch, objects appear to jump. This is why horses sometimes shy away from simple things like a piece of trash on the roadside. To a horse, a harmless piece of white paper, when viewed first with one eye and then by both eyes, seems as if the paper is “attacking” him. When your horse shies or spooks on a ride, allow him to approach the offending object slowly and to view it with both eyes. Once he gets a good look at it and realizes it’s harmless, he will calm down.
Horses also have blind spots. For example, there’s about a four-foot area directly in front of his face where he can’t see. This space varies a little from animal to animal, but four feet is a good average. This is why you should never approach him directly from the front. Have you ever noticed how he lifts his head when approached in this manner? He’s just trying to get a look at whom or what is coming toward him. If you must approach from the front, always speak to him to let him know it’s you and that he’s in no danger.
Another blind spot is the space directly behind your horse. Many new horse owners have suffered a painful kick because they didn’t alert the horse that they were approaching from the rear. The horse didn’t strike out due to meanness. It’s just an old holdover from the days when his distant relatives had to be always on guard from predators. Always speak to your animal when approaching him directly from behind. This will avoid startling your horse and help put him at ease so that he won’t be on the defensive.
Another important area of equine eyesight is night vision. Horses see much better in the dark than do humans; however, it takes them longer to adjust from light to dark. This explains why horses often spook easily at night when going from a lighted area directly to a dark area. Always give your steed a chance to adjust to different degrees of light. The extra time you take could avoid a panicked equine, one that could injure himself or his handler.
Properly understanding a horse’s eyesight is key to explaining much of his behavior and in avoiding negative or dangerous behavior. Horses are powerful, and they can be dangerous, but they seldom act out of anger. Most all equine “aggression” is actually reaction to fear. By following a few important guidelines based on equine physiology, both you and your horse will be happier and safer!