The other day I was talking with a friend and the subject of whether or not dogs see in color came up. My friend stated that he had heard that they did somewhat, but that he didn’t think the colors were as we see them. I wasn’t totally sure, so I decided to do a little research into the topic.
I did indeed find that dogs are not completely colorblind. While dogs do not have the same color vision as humans, they are able to tell yellow from blue. Like a human with red-green colorblindness, they are unable to tell the difference between red and green.
The reason for this limited range, in both the colorblind human and the dog, is that there are only two kinds of colour receptors in the retinas of their eyes. While most humans have three kinds of colour cells, with three different receptor molecules sensitive to blue, greenish-yellow, and red, dogs only have receptors for yellow and greenish-blue.
Canine eyes also lack another human trait: the fovea, an area especially dense with detail-sensing cells. As a result, their detail vision is not as good as ours. But they make up for this by having much better night vision and greater sensitivity to movement.