Re: ARE DOGS COL0R BLIND?

Dear Ray:

Color blindness is the inability to see certain colors. Color vision is controlled by cells in the retina of the eye called cones. The dog does have cone cells in its retina, so it does have the potential to see color. However, the cones comprise only a small percent of the cells in the central area (fovea) of the retina of the dog (probably <10%). Cells in the fovea give the best vision. In man, the fovea contains nearly 100% cones.

Experiments on the dog's eye show that the dog can probably see shades of blue, yellow and gray. Since it cannot see shades of red, the dog is said to have dichromatic (two color) vision compared to people who have trichromatic (three color) vision and can see the full spectrum of colors.

For a dog, not seeing all the colors is probably unimportant. They can use other visual clues such as brightness and position of objects, and their other senses like smell, taste and texture.

You may also want to look an article by Dana Vaughan on Dog Vision. or see an article in the Journal of the American Veterinary Medical Association by Paul E. Miller and Christopher J. Murphy called Vision in Dogs (JAVMA, Vol 207, No. 12, December 15, 1995, pp 1623-1634).