So how does a horse see the world? Our understanding of horses’ vision is not yet perfect, but we are starting to understand quite a bit more. So let’s take a moment to look at some of the basics.
Humans have something called trichromic vision, which means we see four basic unique colours: red, green, blue, and yellow, as well as a range of intermediate hues. In horses, this is not the case. Instead, they have dichromatic vision, which means they can see only TWO basic hues – the ones most similar to yellow and blue.
So what does this mean?
Well, when horses see a mixture of colors from the spectrum, rather than getting an intermediate hue, the result is either white, gray, or a desaturated (less bright) version of one of the two basic hues – that is, a pastel blue or yellow. Below is a good example of the humor color spectrum compared to that of a horse.
And here is an example of what a horse might see compared to what a human would see.
Quality of Eyesight
Color perception is only part of what makes a horse’s visual experience.
A 1992 study showed that horse vision is not as sharp as human sight. If good human vision is 20/20, a horse rates as 20/60. This means that details a person with 20/20 vision can see at 60 meters are only visible to a horse at 20 meters.
There are other factors like motion, depth and spatial abilities, but we won’t get into those in this blog post. Nevertheless, it’s important to know that a horse doesn’t see things in quite the same way as we do!