Do Dogs See Colors?

THE SIMPLE ANSWER —namely, that dogs are color-blind—has been misinterpreted by people as meaning that dogs see no color, but only shades of gray. This conception is wrong. Dogs do see colors, but the colors they see are neither as rich nor as varied as those seen by humans.
The eyes of both people and dogs contain special light-catching cells, called “cones,” that respond to color. Dogs have fewer cones than humans have, suggesting that their color vision is not as rich or intense as ours. However, the trick to seeing color is not just having cones, but having several different types of cones, each tuned to different wavelengths of light. Human beings have three different kinds of cones, and their combined activity allows us to see the full range of colors that characterizes human vision.
The most common types of human color blindness come about because one of the three kinds of cones is missing. An individual with only two cone types can still see some colors, but many fewer than someone with normal color vision sees. This is the situation with dogs, who also have only two kinds of cones.
Jay Neitz at the University of California, Santa Barbara, tested the color vision of dogs. For many test trials, dogs were shown three light panels in a row—two panels of the same color, and a third that was a different color. The dogs’ task was to press the panel that was different in color. Correct responses were rewarded with a treat that the computer delivered to the cup below that panel.

 Neitz confirmed that dogs actually do see color, but many fewer colors than normal humans do. Instead of seeing the rainbow as violet, blue, blue green, green, yellow, orange, and red, dogs would see it as dark blue, light blue, gray, light yellow, darker yellow (sort of brown), and very dark gray. In other words, dogs see the colors of the world as basically yellow, blue, and gray. They see the colors green, yellow, and orange as yellowish, and they see violet and blue as blue. Blue green appears gray.

One amusing or odd fact is that the most popular colors for dog toys today are red or safety orange (the bright orange-red on traffic cones or safety vests). However, red is difficult for dogs to see. It may appear as a very dark brownish gray or perhaps even a black. This means that that bright-red dog toy that is so visible to you may often be difficult for your dog to see. When your own pet version of Lassie runs right past the toy you just tossed, the problem may not be that the dog is stubborn or stupid, but that you chose a toy with a color that is hard for a dog to discriminate from the green grass of your lawn.