DEAR DIDI: My dog has so many toys of all colors and shapes. He has definite preferences, though, so we wonder if he is color blind. He tends to ignore the pretty bright red ones that we thought he would like the most and goes for boring blue! –True Colors in Manteca

DEAR TRUE COLORS: Are dogs colorblind? Yes. Can dogs see color? Yes. You are probably horribly confused now! Let me explain. The eyes of both people and dogs contain special light catching cells called cones. Humans have three types of cones, whereas, dogs only have two types. This means that your dog does see color, but not the full range and intensity that we do. This explains the term “colorblindness” in a human. A colorblind person is missing one type of cone cells and therefore can’t see a certain range of colors.

There have been many tests run in this field. The most efficient test I have read involved shining beams of colored light into the dog’s eyes at an angle. We then analyze the pattern or spectrum of light that is reflected back and then compare it to the pattern that is produced when the same light is shined into human eyes. Colors we see are not necessarily the same as a dog sees them.

Interestingly, the majority of toys on the market for dogs are in the bright red, orange or yellow range, which are not colorful to dogs. Which leads us to believe that those colors are chosen mostly to entice the human to pick it up and take it to the cash register. Your observations of your own dog were spot on. Blue is the key color that dogs can see vividly!

The other type of cells that we have in our eyes are called rods. They are responsible for black and white spectrums and to notice movement. A dog’s rods are much more efficient at this than our own. We can spend 30 minutes trying to track a fly with a swatter in hand while the dog sees that same fly as clearly as a B-52 bomber flying through the room! So a red treat tossed onto a wood floor will be seen very clearly by your pooch while it is still rolling. Once it stops moving they can have difficulty separating the treat from its background.

Toys have other features built-in to entice your dog. Floppy parts, squeakers, and textures all come into play. I love hearing from each of my clients what their dog’s favorite toy is!

Dierdra McElroy is a graduate of Texas A&M University and is an Animal Behaviorist specializing in canines. If you have questions or concerns about the pets in your house, you can get them answered through a future column of Dear Didi. Email your questions or inquire about dog behavior presentations at itsneverthedogsfault@gmail.com.