The world seen from the eyes of a dog appears more blurred and less colorful than ours.
As shown by the comparison between human vision (above) and canine vision (below), "fido" clearly distinguishes blue and yellow, but confuses red, orange, yellow and light green.
For a dog it is almost impossible to recognize an orange ball among many green balls. Remember it the next time you throw an orange ball in the middle of a green lawn!
