Study: Dogs Are Red-Green Colorblind
Researchers have discovered that dogs have difficulty discerning between red and green, much like humans who are colorblind.
Researchers in the department of veterinary medicine at the University of Bari in Italy have found that dogs have a hard time differentiating between red and green, and this could be something trainers want to keep in mind when working on grass or wearing red clothing or shoes.
Dr. Marcello Siniscalchi said that dogs in the wild are most active at dusk or dawn, and they don’t necessarily need color vision. Because we’ve domesticated dogs, and they tend to be more awake in the daytime than ever before, their eyes may not have evolved to differentiate.
The researchers have developed a test which gave them this information, and Dr. Siniscalchi says that dogs being red-green color-blind is important not just for people who are training dogs but for owners who may want to make sure that they have their dog’s full attention.
If playing fetch at the park, for instance, Siniscalchi says that using a blue frisbee or ball instead of red would be advantageous to the dog if it was falling on green grass, and that can generally help the relationship between dogs and their owners.
The researchers used a modified version of a color test for humans. It’s called Ishihara’s test, and it has numbers hidden in colors. People who cannot see the numbers are red-green color-blind. For the dogs, they used an image of a cat instead of numbers.
Dr. Siniscalchi said that dogs acted like humans who can’t see the numbers when they were shown the images, which made them believe they couldn’t see the image. They hypothesized further that dogs had a hard time telling the difference between brown and orange, though they didn’t use those colors in their modified testing.
They hope the research will be used in other animals in the animal kingdom.