The variety of colors we can see in our eyes is nothing compared to the variety of colors the eyes can perceive.
Humans have what is called trichromatic vision. We have three types of photoreceptor cones that allow us to perceive the three primary colors: red, blue, and green.
It is estimated that each of these three cones can perceive up to 100 different shades of colors. When all the cones are combined, we can see a million different color combinations.
Some experts go further, and believe that depending on the person, we could be talking about anywhere between 2.4 and 10 million colors.
Color Vision in Pets
In our pets, the situation is not as good, unless you have an atypical pet like a butterfly or a marine mantis.
Dogs and cats have dichromatism. Unlike us, they have two types of cones instead of three.
Dogs can perceive blues and yellows, but not reds. They see red as yellow. Green appears as gray in their eyes.
The myth that they see in black and white is just that—a myth. Their world consists of yellow, blue, and gray tones.
Cats also cannot see red or green. For them, it’s gray or black.
This detail is important for cat behavior. Buying them toys of those colors will seem less interesting to them because, for them, it’s a boring gray tone.
However, they will feel more comfortable in yellow and blue environments, as they can better perceive what’s around them by being able to see those colors.
Not only do they have one less type of cone than us, but they also have a smaller total number of cones. The human eye has approximately ten times more cone cells than a cat’s eye.
Although both species can see blue and yellow, the human eye is better at distinguishing different shades.
The Eyes of Cats
All of this makes evolutionary sense when we consider that cats are nocturnal hunters. In low light, colors are not as important. In low light, the cat beats us.
Cats have more rod cells in their eyes than we do. The rods are the photoreceptor cells in the retina responsible for peripheral and night vision (and not for colors).
Additionally, they are more sensitive to light than the cones. And they have a greater ability to detect movement.
The peripheral vision of humans is 180 degrees. Each eye covers 130 degrees on its own (which means that a one-eyed person has a significant loss of peripheral vision).
In contrast, cats have a peripheral vision of 200 degrees.
Fun fact: here, dogs are champions with 240 degrees of peripheral vision.
Another detail is the shape of the pupil. Humans have round pupils, like dogs. Cats, however, have vertically elongated pupils.
Their main use is to change their area depending on the light conditions. They can expand and contract over a wider range than the “conventional” round pupils.
Their other function is due to the fact that cats are ambush predators. They need to make an accurate assessment of the distance between them and their prey. The vertical shape helps them achieve sharper vision and better calculation on vertical axes.
Ironically, cats see worse up close. This is partly due to the fact that their eyes are very large in proportion to their heads and the ocular muscles have trouble regulating light at such close distances.
Objects that are 25 centimeters away, or closer, become blurry and they can’t focus on them. That’s why cats can jump great distances with incredible precision, but when trying to grab something right next to them, they move their paw with the clumsiness of a drunk.
Their whiskers are specifically designed to compensate for this flaw. They help them navigate what is near their face.
At greater distances, once again, we beat them. Between 30 and 60 meters away, in general, our vision is sharper than theirs. Beyond 60 meters, we’re not doing that great either, so let’s call it a tie.
Fun fact: cats have a blind spot in the area of their chin. If you place something under their nose, they can’t see it.
The Nighttime Secret Weapon: The Tapetum Lucidum
As nocturnal predators, their eyes have one last trick: the tapetum lucidum. It is a layer of tissue located behind the retina, similar to a mirror, which reflects light back to the photoreceptors.
In cats, this can increase the amount of light reaching them by up to 40%.
It is not unique to felines but rather a common adaptation for many animals (especially predators) with nocturnal lifestyles. Dogs, crocodiles, and others also have it. However, primates like us, squirrels, and most birds (with exceptions like owls) do not.
This specialized tissue is the reason why some animals’ eyes glow in the dark.
Unfortunately, the tapetum lucidum is not a structure that can be removed or used at will. Even with its ability to contract the pupil, during peak daylight hours, their eyes become saturated with brightness and lose definition.
Taking all this into account, cats see between six and eight times better in the dark than the average human.
This is true for all cat breeds, even though their eyes may not be identical.
You may have noticed that some breeds have eyes that are different in size relative to their bodies. It doesn’t matter if it’s the large eyes of the Siamese or the small, fixed eyes of the Persian. They all work the same way.
If you ever want to surprise your cat with affection, take advantage of midday and try to get as close to their face as possible as quickly as you can.
All of this we’ve mentioned applies in normal health conditions. Clearly, cats are not immune to vision-related diseases, such as progressive retinal atrophy. If your cat seems to have eye problems, our recommendation is to get them checked as soon as possible.
Whether they have problems or not, our recommendation is to get them a genetic test from Koko Genetics.