Dogs' eyes are focused on a spectrum containing yellows, blues, and violets.
Red, green, and orange as we see it would appear as yellow or blue. I'm guessing my lush green yard looks like a yellow field with yellow bushes carrying yellow flowers.
It's interesting how many dog toys are yellow, orange, or red, because this lets us see them better. From the dog's point of view, a blue tennis ball might be much more visible than a yellow one. They find them anyway, because dogs have a great sense of spotting movement.
|Image source: http://www4.uwsp.edu/psych/dog/la/davis2.htm|
An eye contains two types of photoreceptors: rods and cones. If I got this right, a human eye has many types of cones, which allows us to see many different colors. A doggie eye has more rods. Thus, dogs have much better night vision and ability to track movement than the human eye. On the downside, they see fewer colors and less details.
There's another big difference between a dog's eyes and a human's. Their eyes are placed on the sides of the head while ours face forward. This means that they get a visual field of 250 degrees, and humans only have a field of 190 degrees.
|Image source: findretrievers.com|
~ Maria Sadowski ~