Horse Vision

They say it’s good to try to see the world through someone else’s eyes - to imagine life from their perspective. We may not be able to get a horse’s-eye view of the world, but learning about horses’ vision helps us understand why they act the way they do. In this post, we explore horses’ eyes and sense of sight.

Horse Eyes

Horses have the largest eyes of all land mammals - 8 times larger than human ones. These huge eyeballs make objects appear larger to horses than they do to humans.

Horse eyes are generally brown but may also be blue, green, yellow, amber, or hazel. Having non-brown eyes is often linked to the horse’s coat colour.

Although people sometimes think horses are colour-blind, they can see green and blue. Red, however, may appear to horses as green or yellowish, grey, or brown.

Equine eyes have trouble picking up details. Horses typically have 20/30 vision, compared to humans’ gold standard of 20/20 vision. What that means is that, what a human with good vision can see in detail from 30 feet away, a horse can only see clearly from 20 feet away.

Like humans, horses can be nearsighted or farsighted. They can also suffer from other eye problems.

Horses do have better night vision than humans and even see better on a cloudy day than a sunny one. On the other hand, they take longer than humans to adapt to a sudden change between light and dark.

Unlike humans’ round pupils, horse pupils are horizontal. This feature of grazing animals gives them panoramic vision along the ground, helping them spot predators and see clearly while they’re fleeing. Interestingly, the eyes rotate as the animal grazes so that its pupils remain horizontal.

Range of Horse Vision

Horses’ eyes are on the side of their head, giving them 350° of vision. Most of that vision is monocular, meaning that they see separate images on either side of their head. Horses’ perception of peripheral motion is keen, and they can move their eyes independently to scan for predators.

It sometimes seems like a horse does not recognize with its right eye an object that it saw previously with only its left eye. Although the 2 parts of a horse’s brain do connect, the animal may not recognize an object seen from a different angle or with different lighting.

Horses do also employ binocular vision - vision that uses both eyes at the same time. The range is about 65° in a triangular shape in front of the horse’s face. Since depth perception works best with binocular vision, and horses’ vision is mostly monocular, they have some trouble determining relative distance.

They also have 2 blind spots: one directly behind them, and one in front of their face. The front blind spot extends from the horse’s eye level down to the ground.  It’s hard for us to imagine, but horses can’t see the grass as they’re grazing, and objects faced head-on seem to disappear if they get too close.

To make up for their vision limitations, horses use their whiskers to sense objects in their blind spot. They also move their head to get a better view.

Did you learn something new about horses’ vision? Let us know in the comments!