Are Dogs and Cats Colorblind?

If social media is anything to go by, dog and cat vision are certainly having a moment, especially on TikTok, where it seems like practically every pet-owning user has accessed the platform’s wildly popular dog- and cat-vision filters.

Sooner or later, anyone with a dog or cat is bound to wonder how their pet sees the world. But are apps and filters really a good representation? Let’s take a look at what our furry friends can and can’t see compared to us. 

At a fundamental, structural level, the eyes of dogs and cats are actually quite similar to humans: We all have retinas at the backs of our eyes, and they all work the same way. When we look at something, light hits this layer of tissue, which then converts that light into an electrical impulse. That impulse travels along the optic nerve to the brain and voilà: What you get is what you see.

Contained within the retina, both humans and their pets possess light-sensitive cells or photoreceptors called rods and cones. Basically, cones are the cells that allow us to see colors and fine details while rods are the receptor cells that enable us to detect motion or perceive our surroundings in low light.

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Most people have what’s called trichromatic vision, meaning that the cones in our eyes can perceive three primary colors: red, blue and green and that the wavelengths of these three colors can be combined to create any color in our brains. That's great for humanity, but here’s where our visual perception starts to differ from our furry friends. 

In canine eyes, rods are more dominant than cones. This dominance gives dogs superior motion-related vision and the ability to see far better than humans can in the dark. On the other hand, dog retinas have only two types of cone cells — this is known as dichromatic vision — so their perception of color is limited, but by no means absent. Dogs can see blue-violet and pale yellow hues. They can also discern different shades of gray fairly well. But they can’t see green, orange or red.

In normal light, dogs can’t see as far as humans, either — the comparison that’s usually given is that dogs can see objects at 20 feet that humans can see at 75 feet. 

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But don’t feel bad for your dog. In many ways, their vision far exceeds our own. In addition to their ability to see better in low light, their wider field of vision allows them to perceive a broader range of things that we would have to swivel our heads to view. And new research has shown that in canine brains, visual perception and their exceptional sense of smell are integrated in a manner that may allow dogs to "see" their surroundings in ways that humans can’t possibly imagine. 

Cats, meanwhile, are trichromats, although not in the same way that humans are. Like dogs, cats have rod-dominant retinas, which give them exceptional night vision and the highly sensitive ability to detect motion. Also like dogs, cats are better at seeing blues and yellows.

But unlike our canine pals, and contrary to what many owners might think, current research indicates that cats also have cone cells that allow them to see some greens, too. In that regard, their color perception may be slightly closer to that of a human. But the colors your cat can perceive are likely to appear washed out and not terribly vibrant.

Cats are also not very eagle-eyed. What humans can see at 100 to 200 feet, cats can only see at about 20 feet; after that, their world gets fuzzy in a hurry. 

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And as good as their night vision might be, it’s a myth that cats can see in the dark. It’s more accurate to say that they can see very well in very low light. This is thanks not only to the density of rod cells in their retinas but also to the fact that cats are able to open their pupils much more widely than humans. This allows the maximum possible amount of light to hit the retina, giving kitties the ability to see as much as eight times better in a darkened (but not completely dark) setting than their human companions can. 

Cats in particular have a reputation for those spooky glowing eyes that we see in photos — or that sometimes startle us in the middle of the night. Lots of other animals have this characteristic, though, including dogs and horses.

That’s because these animals possess something that human eyes do not: a lining of tissue behind the retina known as the tapetum lucidum. The tapetum functions as a retroreflector, meaning that it bounces light back through the retina, thus increasing the amount of overall light available to the animal’s photoreceptors. This only increases your pet’s ability to see in low light, although the reflected light may make their vision somewhat blurry. The “glowing” effect that we see in our pets’ eyes is actually just light bouncing off the tapetum.

So, while our dogs and cats may not be able to see with the same sharpness or colorful vibrance as humans, their eyes can do things that would seem superhuman to us. Reflect on that the next time you engage your favorite dog- or cat-vision app and try to envision your surroundings as they do. For them, it's a whole different worldview. 

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