We share so much time with our horses, taking in the world around us--in the ring, on trails, and at shows. Have you ever wondered if they see the world differently than we do? In addition to the difference in the placement of horses' eyes, there are a number of ways that our equine partners see differently than we do; one of which is the colors that they see.
Cones are the reason that humans and animals can see color. Found in the retina, these photoreceptors are sensitive to different wavelengths of light. Horses have blue-sensitive cones and yellow-sensitive cones, whereas humans carry those cells in addition to red-sensitive cones. Therefore, horses can't see as many colors as humans can (but they can see better at night than we can...so we're kind of even, right?). Equine vision is limited to shades of blues and greens, but nothing on the red spectrum, which includes shades of purple, orange, and red. The spectrum of color vision that horses are equipped with is called dichromatic vision, because they have two types of cone cells. Dogs and cats, like horses, also have dichromatic vision, whereas humans possess trichromatic vision.
While humans see a more vibrant spectrum of colors than horses do, horses still get to experience many beautiful colors in nature.