Why Do Siamese Cats Have Round Pupils

Cats are known for having cat-eyes, which means having a slit pupil that goes right down the middle of the iris. But not all cats have cat eyes. Some have other kinds of pupils due to mutations and the many environments domesticated cats have lived in. 

Siamese cats, for instance, have naturally round pupils very similar to human eyes. 

But why do cats have different kinds of eyes? 

Siamese cats have round pupils thanks to a mutation. Like many of their other traits, the mutation has been supported by consistent breeding efforts to maintain the classic Siamese cat look. However, unlike the mutation that gave Siamese cats crossed eyes for a long time, the round pupil gene doesn’t harm Siamese cats or cats with the same eyes.

Breeders aren’t trying to change them, and Siamese cats will likely have round eyes as long as there are Siamese cats. 

Here’s what you need to know about Siamese cats, their eyes, and how your cat sees and navigates the world. 

What Breeds Of Cat Have Round Pupils? 

Siamese cats aren’t the only cats that have round pupils, either. A few other breeds also have round pupils, some of them because they are related to Siamese cats and inherited round eyes. 

Pallas, Russian Blue, Sphynx, Exotic Shorthair, British Shorthair, Persian, and Scottish Fold cats all have round pupils at least some of the time, though Siamese cats may have this feature more obviously than some other breeds. 

Other cats mixed with any of these breeds may also have round pupils if they inherit the mutations that cause round eyes. 

In rare instances, cats may also be born with the round-eye gene spontaneously occurring, though they usually aren’t allowed to breed because only a few breeds accept round pupils as breed-standard traits. 

One thing is for sure, though, if you have a cat with round pupils, whether they are a Siamese cat or not, you have a very special cat. 

Why Do Most Cats Have Snake Eyes? 

Cats are designed to be powerful predators, from the smallest to the largest Tigers. Their eyes are a part of that powerful design, from their close attention to movement in the world around them to their pupils that dilate easily thanks to the light in their environment. 

The slit pupils most cats have are that size and shape help them see movement clearly while also controlling how much light makes it into their eyes. 

Cats are crepuscular animals, which means they are most naturally active around dawn and dusk. They aren’t designed for the bright light at noon or the total darkness at night. However, because they have eyes that can filter the light, they can see perfectly clearly even when other animals can’t, and they can protect their eyes from damaging light if they’re up and about during the day. 

Cats with round pupils can do this too, but their ability to filter the light is less effective than the slit-pupil shape. 

Do Round Eyes Have Advantages For Siamese Cats? 

Siamese cats have several advantages and disadvantages regarding the unique mutations that make them what they are. 

Regarding eye shape, Siamese cats can have a harder time in bright light because their eyes won’t filter out the light like other cats. However, Siamese cats have some advantages that help balance the problems with their pupil shape. 

The most important advantage is that Siamese cats see better in dim light than other cats. That’s a huge advantage for them because cats are crepuscular, so they are most active in dim light conditions.

Unfortunately, Siamese cats can also be prone to getting eye damage, which often negates the advantages they get when their eyes are in good condition and working properly. 

Do Siamese Cats See In Color? 

All cats see some colors, including Siamese cats, unless they have inherited some color blindness. 

Siamese and other cats can see in the yellow-green and blue-purple color ranges, but they don’t see the red-orange part of our visible spectrum. That means that they have significantly fewer colors they see clearly and that a lot more things are shades of gray than in our vision. 

Color isn’t as important for their vision, either. Cats are more attuned to movement and changes in the light than we are, and their limited color range is much less important for telling them where they need to be or where their prey is hiding. 

That’s important because color-blind cats have significantly fewer disadvantages than we do. Light is important, but the color of that light doesn’t matter nearly as much. 

What Colors Do Cats See Best? 

Cats can generally see blues, greens, yellows, and some purples best, but they won’t see any of those colors the same way we do. 

That’s because all but the purest shades of each color, neon colors or the very most vibrant, will have at least a small amount of red and orange in our sight. Since cats don’t see the red and orange parts of the color spectrum, the colors they can see will all look slightly different. 

The more red or orange there is in color, the more likely a cat is to see that color as a shade of gray. 

Things To Consider

Taking care of your Siamese cat’s eyesight is essential to their daily care. Any cat with round pupils needs a little extra support to protect its eyesight and ensure it can enjoy all the beautiful sights in life for as long as possible. 

Talk to your vet about foods and treats that can help support good eyesight in your cat. A balanced diet is vital for maintaining sight, so you don’t want to skip it. 

You should also consider things like getting window film to reduce the intensity of noon light, at least for your cat’s favorite windows, turning off the lights when you leave a room, or even changing the kinds of bulbs you use so that the light isn’t as intense. 

You should also give your Siamese cat a few dark or dim places to retreat to when bright lights get too intense. That way, they can at least give their eyes breaks, even if things are too light most of the time. 

Remember, eye issues are common in Siamese cats. It’s possible to do everything right and still have your cat develop sight problems. 

The good news is that indoor cats can adjust to having sight problems pretty easily, so as long as you’re willing to work with your cat and help them navigate the world a little, they should be able to live every day happy, healthy lives, even if they do develop eye trouble.