Are Dogs Color Blind?
One of the most common questions people ask about their dog’s vision is “are dogs color blind?”
The answer to this question isn’t as straightforward as it may seem. Dogs are thought to be primarily dichromatic, which means that they have only two cones for perceiving color, while humans are trichromatic—for us, red, green, and blue light each activate a different cone in our eyes. But even if dogs perceive fewer colors than we do, it doesn’t necessarily follow that they see the same thing we do when we look at a rainbow or a traffic light.
The question of canine color vision is more complicated than you may think! Let’s explore how dogs see color, and what they might actually be able to see. And if you’re curious about whether dogs can see as well as we do in the dark, check out this article: Do Dogs See In The Dark
A Dichromatic Eye
Dogs contain both rod cells and cone cells; however, most of their cones are thought to be insensitive to all but the long wavelength of light, which means that they are essentially red-green color blind.
Cones are cells found in the retina of mammalian eyes, including those of humans and dogs, that respond to different wavelengths of light. Humans have three kinds of cones, each containing a different pigment that is most responsive to either short, medium, or long wavelengths of light. The specific range of responsiveness for each kind of cone is known as its “spectrum.”
When people are referred to as being color blind it usually means that they have trouble seeing the difference between certain colors, but this isn’t always true. Some people, called anomalous trichromats, have three working cones but the sensitivities of their cones don’t overlap. This means that they perceive more or fewer colors than people with normal color vision do.
Dogs are hypothesized to be mostly dichromatic—meaning that they have only two kinds of functional cone cells in their eyes. The canine retina contains both rods and cones, but the majority of cones in dogs are thought to be insensitive to all but the long-wavelength light.
It’s important to remember that dogs are highly evolved predators, so they have many finely tuned senses. While they do see colors differently than humans, they probably don’t perceive the difference between a red ball and a green one or even notice these colors at all. They definitely can discriminate between different colors, but it’s unlikely that their perceptions of color are the same as ours.
