Slit vs Round Pupils: Why Do Some Cats Have Differently Shaped Pupils?
The shape of your cat's pupil has a lot to do with how they spend their days.
Published Feb. 12 2025, 4:59 p.m. ET
There are several stereotypes about cats, including their ability to always land on their feet, their love of tuna fish, and their curiosity. But, there's another thing that cats are known for that you may not immediately think of when you picture your favorite feline: their slit-shaped pupils.
Unlike humans, domesticated cats have slit pupils that run vertically from the top of their eye to the bottom, sitting in the center. Those slits can sometimes appear larger or smaller depending on light conditions.
Now, you may find yourself asking why domesticated cats have slit pupils, especially when so many other species of cats don't. Surprisingly enough, it has a lot to do with the generational lifestyle choices of the cats in question.
Cats need the slits to see in low-light conditions.
Unlike lions and tigers — both of whom have round pupils similar to humans — small cat species and domesticated varieties mostly hunt at night, which is why their pupils adapted into slits to allow them to see better, according to the Turpentine Creek blog.
These slits allow them to see clearly during all kinds of lighting conditions, which is essential to their survival.
Vertical pupils can help those animals who are lower to the ground.
Cats aren't the only creatures with slit pupils. According to a 2015 study from the journal Science Advances, and animals like snakes and crocodiles also have the same unusual pupil shape.
One theory about the why behind this seems to indicate an evolutionary change in animals lower to the ground since it gives them a better competitive edge when hunting.
The slits allow them to attack from a distance.
If you've ever watched a collection of funny cat videos, chances are you caught at least one featuring a cat crouched down in attack mode with their little butt wiggling up in the air as they prepared to pounce.
Believe it or not, the Turpentine Creek blog says that the slit pupils help cats with this function, allowing them to better assess the distance between themselves and their prey. This is called stereopsis, and it changes how an animal's brain processes information.
Slit pupils help them stay stealthy during the hunt.
While lions and tigers may have the brute strength and stamina to chase down large game across great distances, domestic cats rely more on their ability to move unnoticed across their hunting grounds.
The Turpentine Creek blog says their eye shape evolved to make it easier for them to track what they're hunting, allowing them to get closer before going in for the kill.
Cats can see a range of colors.
According to the BBC, slit pupils are a sign of having "multifocal" lenses. Amongst other things, multifocal lenses allow animals to focus on different colors.
Why would this be important to cats? Well, think about some of their favorite prey: birds. Male birds are typically more colorful than their female counterparts. Seeing bright colors like red, blue, and yellow against the backdrop of green grass could prove especially useful for a cat.
While experts are still learning a lot about the reason for different pupil shapes, it's interesting to learn all the theories they've already come up with about the cat's unique looking eyes.