The horse’s vision is very different from that of us humans. As a result, it experiences the world very differently than we do. This information is important if we want to understand how a horse reacts to its environment. In this article we will discuss how the horse sees the world and how it reacts to it.
A horse has the largest eyes of all land animals. It is a prey animal and therefore has its eyes on the side of the head. This is a big difference from us humans and other predators, who have eyes at the front of the head. The reason for this is that prey animals must have a wide field of view, so that they can keep a close eye on the environment for possible dangers. Predators, on the other hand, have limited vision, but binocular (with two eyes) so that they can focus and see depth well. This again comes in handy when hunting a prey animal.
The horse’s field of view is very wide: almost 350 degrees. This field of view is monocular for about 285 degrees. That means that the horse sees this with one eye. He sees the remaining 65 degrees binocularly, so with both eyes. This is also the part where the horse can see depth, but not as well as us humans. You may have noticed while working with horses that something the horse has already seen out of its left eye can be totally new on the right. This is because the two hemispheres of the horse’s brain communicate little with each other. It is thought that about 10 to 15% of information trickles through. Therefore, things that the horse perceives with the left eye may not arrive in the right hemisphere of the brain. In your training it is therefore important to show a horse something on both sides. In addition, the horse has two narrow blind spots: the area directly behind him and directly in front of and under its nose. This is one reason why your horse may spook if you approach them straight from behind without warning.
Unlike humans, horses do not focus by contracting or relaxing their pupils. The horse’s eye has a horizontal band in the middle of the retina. On this band, the eye sees images much sharper than above or below this band. To see clearly, the horse must move its head up or down. That’s why you see horses raise their heads when they approach an obstacle: this way they focus on the obstacle so that they can better estimate distance and depth. However, when the horse is about 2 meters in front of the obstacle, it can no longer see it clearly. They then have to trust their instincts and the rider’s aids.
A lot of research is still being done into which colours a horse actually sees. It seems that horses are so-called dichromats. This means that they have two of the three types of cone cells in their eye. Cones are light-sensitive cells that perceive the colours red, green or blue. Horses can therefore distinguish colours, but less well than us humans (we do have all three types of cone cells). You can compare this to a person who is colour blind. A horse can distinguish blue, yellow, white and shades of grey well from each other, but hardly red and green.
As you can see, there are clear differences in the vision of humans and horses. It is helpful to keep these differences in mind as it can benefit you in your interactions with horses.