CJAMY. Camille Gaubert’s column is broadcast daily on “C Jamy,” hosted by Jamy Gourmaud from Monday to Friday at 5 p.m.
The horse’s field of view, which covers almost 360 °, is impressive. Yet their vision is far from perfect.
Panoramic vision based on movement
Thanks to the position of the eyes on the sides of the head rather than the front like us, they can see almost 360 ° around them. But they still have “blind angle of 60 °, inclined downwards in front of the eyes, slightly below the muzzle“as well as behind the truncheon, explains Thomas Launois, a veterinarian at the Dammarie-les-lys veterinary clinic. But they just need to move their head down or to the side to correct this small flaw.
If this panoramic view is crucial, it is because the horse is prey by nature, unlike us humans who are predators. “He sees shapes better when things move, and quite badly if things don’t move.“, explains Thomas Launois. This allows him to see the predators approaching and to choose the best escape route at any time. But moving too fast can also lose him. “If we get there too fast, he won’t even see the movement because his retina has a slow sensitivity”, specifies the veterinarian. Horse photoreceptors – eye cells that receive light – slowly transmit information to the brain. That’s why it takes a long time for a horse to get used to the darkness: about half an hour compared to a few minutes for us.
The biggest eyes of all terrestrial mammals see the world in pastel
Fortunately, when there is no light, a horse can still rely on the size of its eyes. Indeed, it is a terrestrial mammal that has the largest eyes in the world: only a whale, an ostrich and a seal have defeated it! Most importantly, horses have special pupils. The pupil is that black circle we have in the middle of the eye that shrinks or expands to control the amount of light that enters the eye. In horses, they are wide and horizontal, allowing them to better perceive light on the sides of the eye.
And even in broad daylight, we would be incapable of appreciating certain nuances of our visual world in the same way we do. We humans really have trichromatic vision: we see blue, red and green. But horses, like most mammals, have dichromatic vision and have difficulty seeing red. In addition, even the colors she observes are pastel because her cones — color-taking photoreceptors — are less sensitive than ours, according to Thomas Launois.