Through the Eyes of a Dog
Have you ever looked at your pooch and thought about what it might be like to see things from his eyes? It’s been long believed that our canine companions see only in black and white, and that levels of lightness and darkness help him differentiate between objects. Thanks to recent research, these theories have been put in the doghouse!
Earlier this decade, U.S. researchers discovered dogs have only two cone photoreceptors (the part of the eye that controls the perception of color), unlike humans who have three, allowing us to see all three primary colors – red, yellow and green. Since dogs have only two cone photoreceptors, they should be able to see some colors, but not others.
In 2013, a team of researchers from the Laboratory of Sensory Processing at the Russian Academy of Sciences built upon this finding to determine if dogs do in fact see colors and if they can distinguish between them. They tested the vision of eight dogs of different sizes and breeds. For one test, the researchers used four pieces of paper, one colored dark yellow, one light yellow, one dark blue, and the last light blue. Selecting two papers that differed both in color and in darkness (for example, light yellow and dark blue), the researchers would place one paper in front of a box that contained a bit of raw meat, and the other in front of a box that contained nothing. For each trial, the dogs would be allowed to open only one box.
After only a few trials, each of the eight subject dogs learned to correctly choose which box held the raw meat. This result indicated they were trained to associate the meat treat with a specific piece of colored paper. For example, to the dogs, dark yellow equaled meat.
Researchers then switched things up by changing the color of the paper that was put in front of the box that contained the meat. In the end, it was apparent the dogs had memorized the color that was associated with the raw meat, not whether it was light or dark. This testing proved, not only do dogs have color vision, but they consciously use it.
While it has been proven our four-legged friends do indeed see colors, their color palette appears to be limited to shades of blue, yellow and gray. It has also be found their visual acuity is only 20 – 40 percent that of a human’s, meaning an item in the distance that appears clear to a human may appear blurry to a dog. On the other hand, they are able to see better in darkness that humans and can detect movement more easily. So, where they lack in some visual areas when compared to their pet parents, they excel in others. While they may not see the full color world we see, if they could talk, I’m sure they would agree it is a beautiful one!