Equine VisionWhat a horse sees are in images C and D. Nte that fluorescent orange is seen as almost the same color as the grass. When a carriage horse is flying through a course made of traffic cones, the cones and the grass there are set on are almost the same color. Now check out the vision of birds below!
Real life implications of dichromatic color vision for the horse. Two unaltered digital images (A,B) and digitally altered (C,D) forms of the same pictures simulate the dichromatic color vision of the horse. A computer algorithm was used to simulate how each color in the original picture would appear to a dichromatic horse possessing visual pigments with the spectra determined in this study. To more closely approximate the horse’s visual experience, the images were also adjusted to take into account the decreased spatial acuity of the horse.
Birds are tetrachromats, they see four colors: UV, blue, green and red, whereas humans are trichromats and can only see three colors: blue, green, red. Hence the differences in vision below. Bear in mind, that the magenta UV ‘color’ shown here has been chosen to make it visible for us humans, it is a ‘false color’, as per definition UV light has no color.