It’s well-known that cats don’t see color like we do. But are cats color blind like dogs, or do they see color like we do? Or, maybe, do color blind cats even see the world in black and white?
Do cats see color? They do, but not quite like we do. Cats see the world the same way as people with red-green color blindness. Color-blind people lack one or more of the three kinds of cone in the retina, cones being a color-sensitive photoreceptor. Cats have two kinds of cone, with a gap in their color perception in the same place as a red-green color blind person (at roughly the wavelength of green). Colors therefore appear different and muddier, especially red and green. Cats can still distinguish red or green from other colors, but not from each other.
The guide below first answers the core question—do house cats see color—before addressing what that really means in practise. By looking at scientific studies, we can put this question to bed once and for all!
Are Cats Color Blind: Yes or No?
Cats are color blind, but this might not mean what you think it means.
Cats can see colors. However, they don’t see color in the exact same way that we do; furthermore, their vision is different to ours in other ways, like how far they can see and how detailed things are. What’s interesting, though, is actually how little we know about how cats see the world. Studies have variously suggested that cats can hardly see color at all, while others say that their vision is like that of a dog. Let’s take a look at the science to see what we can learn!
What Colors Can Cats See?
Recent research is always a good place to start. One paper published in the journal Experimental Eye Research looked at cat vision to figure out what colors they can see, and summarized what we know quite well:
Despite extensive study, the basic nature of feline spectral sensitivity is still unresolved.
In other words, we’ve been trying to figure out for years which colors cats can see precisely, but we still haven’t managed it.
Do Cats See in Black and White?
Being color blind doesn’t necessarily mean being unable to see color. This is a common misconception that people make. There are all sorts of color blindness, and it’s only the least common of these that means seeing in black and white.
It all comes down to what kinds of cone you have in your eye, ‘cones’ being light- and color-sensitive cells. You’re probably already familiar with the terms ‘rod and cone’: rods and cones are specialized cells in the retina responsible for color vision and nighttime vision. Cones are for color and rods are for seeing at night. If you have normal color vision, your eye has three different kinds of cone responsible for seeing colors at different points along the color spectrum… In other words, one for green, one for blue, and one for red.
The most common kind of color blindness is red-green color blindness. This occurs when either the green or red cones are absent, meaning that the person struggles to distinguish between reds and greens; at the same time, though, yellow and blue colors stand out more than for a person with three kinds of cone. Blue-yellow color blindness is the second-most common, where the blue cones are affected. A complete lack of cones, meaning that the person sees in black and white, is very rare indeed.
All that is very interesting—but what about cats?
Are Cats Trichromats or Dichromats (Do Cats See in FULL Color)?
A trichromat is an animal that has three kinds of cone. A dichromat is one that has two kinds of cone, just like a person who has red-green or blue-yellow color blindness. Many animals are dichromats. The paper in the journal linked above addressed precisely this issue:
Most electrophysiological studies have demonstrated two photopic receptors within the cat’s retina, one most sensitive to longer wavelengths near 560 nm and the other most sensitive to shorter wavelengths near 460 nm, providing the neuroretinal basis for dichromatic vision. A few studies, however, have detected a third photopic receptor most sensitive to medium wavelengths between 500 and 520 nm, overlapping in spectrally sensitivity with the feline scotopic receptor, that potentially could allow trichromatic vision. Indeed, one behavioral study has demonstrated trichromatic vision in cats, but a flaw within its experimental design raises the possibility that achromatic intensity cues might have allowed the accurate identification of medium wavelength targets.
Let’s break down what that means. First, the paper talks about ‘photoptic receptors’ in the retina, by which they mean cones: they found evidence for two kinds of cone. But crucially, a select few studies have found a ‘third photopic receptor’, i.e. a third kind of cone, which would suggest that cats are trichromatic. If they were, then they would see color largely like we do. The paper goes on to describe the test that these scientists ran, the purpose of which was to search for this potential third kind of cone:
This study tested for a spectral neutral point in the domestic cat using a two-choice discrimination task.
Here, the scientists explain that they are trying to find the mid-point they described above. Some studies suggest that cats may recognize colors of wavelengths between those that their two cones specialize in, which is what the hypothetical third cone would allow them to see.
The positive targets were created using monochromatic light from various single wavelength light emitting diodes (LEDs) combined with a white light of variable intensity, while the negative targets were created using white light of variable intensity. Trials were performed with varying intensities of positive and negative targets, from brighter positive targets to brighter negative targets, to eliminate achromatic intensity cues. Two cats with prior experience with two-choice discrimination tasks, one male and one female, successfully discriminated monochromatic light from 456 nm to 497 nm and from 510 nm to 524 nm, but both failed to discriminate monochromatic light at 505 nm over multiple trials.
This particular study suggests that there is a gap within the cat’s color vision; a wavelength that cats can’t see, not at the edge of the spectrum like infrared or ultraviolet, but right in the middle.
These results provide strong evidence that cats are dichromatic with a neutral point near 505 nm. This neutral point is nearly identical to the neutral point of the human deuteuranope, making feline vision a more accurate a model for red-green colorblind individuals than normal trichromats.
Being dichromatic, then, cats see color similarly to a color-blind person. Even more remarkably, the part of the color spectrum that cats can’t see corresponds almost exactly to the part that red-green color blind people can’t see. In other words, cats see color like red-green color blind people.
Can Cats See Red?
Despite being red-green color blind, that doesn’t mean your cat ‘can’t see red’. It isn’t that everything in your cat’s world looks normal, apart from red things, which are gray—that’s not how it works. The reality is a little more subtle, and to understand how and why, you have to understand how light works.
Colors aren’t just… Colors. Colors are made of a combination of other colors. That’s why you can get any color on earth from a simple RGB color value. Purple, for example, is a half-and-half mixture of red and blue.
What this means is that your cat, or a color blind person, can’t see the redness of these colors in the same way that trichromats see them. If the color doesn’t contain any red or green—like a perfect blue, for example—it looks roughly the same. But everything else is subtly changed.
Put simply, yes: your cat can see red. But it doesn’t look like the red that you see. Instead, it looks more like a washed out brown, like a muddy or khaki color. The same applies to green, which looks browner. This means that your cat can distinguish between something that’s red and, say, blue, but has difficulty distinguishing red from green.
Can Cats See Blue?
Yes. It’s likely that a cat’s ‘blue’ is similar to our perception of ‘blue’.
We can know this because blue light has a clearly defined wavelength. While many things related to color are to do with perception—and so are difficult to define—this is one thing that’s not! Blue light ranges from about 400nm to 500nm, which you likely remember from above is a wavelength that cats can distinguish from other ones. But as the blueness of the light becomes greenness at 500nm and upwards, that’s when cat’s struggle to distinguish it.
There have been specific tests that look at whether cats can tell blue from other colors. This one, for example, tested cats with blue lights, which were compared with red or orange ones. Cats didn’t find this difficult even when there was bright natural light around, indicating that they really do have cones for detecting blue light (just like we do).
Can Cats See Green?
Red-green color blindness, obviously, affects red and green primarily. But again, this doesn’t mean that your cat can see everything in full color apart from red and green, which appear gray. Rather, it’s that red and green look different to what we see. The best comparison is to a kind of muted khaki color (i.e. brown).
Something that becomes difficult is distinguishing between red and green. If you place a red object and a green object in front of a cat, it won’t perceive them as two different colors—at least according to the latest science. There’s always a chance that further research will prove or disprove what we currently know!
Why Are Cats Color Blind?
When a person is color blind, it’s because they have inherited a genetic change from their parents. You can carry the color blindness gene without expressing it, which is common in women; but because the gene is located on the X chromosome, and men only have one of these, it’s more likely for a man to have it.
Cats aren’t color blind for the same reason. The way that a cat’s eye grows does depend on genetics, but color blindness in cats isn’t the result of a genetic anomaly. ‘Color blind’ is the way that a cat’s eye is ‘supposed’ to be.
Anatomical Differences Between the Human and Cat Eye
The core difference between a cat’s eye and a human’s eye is in the retina.
According to the Cambridge English Dictionary, the retina is “the area at the back of the eye that receives light and sends pictures of what the eye sees to the brain.” It’s located behind the pupil and lens, and connects to the optic nerve. It plays a big role in how well an animal can see.
In this context, the retina is important because it contains the eye’s rods and cones. The human retina has around ten to twelve times as many cones as a cat’s eye, meaning we see colors as brighter and easier to distinguish from one another. Since cones are also responsible for motion detection during the day, we’re better at that too.
Since cats have fewer cone photoreceptors, they have lots of space for rods. That’s why cats have much, much better night-vision than we do.
Why Don’t Cats See the Colors We See?
One interesting idea is that cats can’t see color as well as we can because their diets don’t depend on color like ours do. Humans evolved to eat a very wide range of foods, wider than most other animals. Early people didn’t eat anywhere near as much meat as we did, and of course, had to forage for their own foods. As such, they had to tell ripe berries from unripe ones, or colorful-but-poisonous mushrooms from ones that are edible. This is especially relevant to fruits, which are often subtle shades of red or green. Cats don’t face the same task, as they are obligatory carnivores: if it’s a tiny mouse, your cat can eat it, with no question of whether it’s ‘ripe’ or not!
What cats do need, though, is good night vision. Cats like to hunt at night, and the better they can see at night, the more effectively they can hunt. That’s why they have more rod photoreceptors and fewer cone photoreceptors—they’re simply more useful to a cat.
Aside from that, it’s just a matter of evolution. Not every animal has evolved ‘perfectly’, which is why some people go bald at 18.