Raising Your Paws - Your Pet Parent Resource

What that Distinctive Vertical Slit in Your Cat’s Eye Is About.

Published: 10/22/2019

Its Halloween time, and you’ll see many images of the black cats with their slitted eyes. It seems that for us, we associate animals, with eyes that have those vertical slits, like crocodiles and snakes and Harry Potter’s Voldemort, with being creepy, scary and threatening.


Some of the reason we perceive it as scary is that their eyes are different from ours.

Humans, (tigers and lions, as well) have round pupils and when bright light hits the eye, our pupils shrink or constrict to a tiny round pin prick size and shape. The constriction of the pupils is what stops too much light from getting in the eye which would damage our retinas.

In domestic cats however, their pupils are vertically shaped, not round, so when bright light, enter their eyes, to protect the retina, their pupils constrict into a narrow vertical slit. The cat’s vertical pupil shape is a real benefit, able to open wide, to an almost completely round shape, to let a lot of light in, when its dark out, to narrowing to a tiny slit to reduce the amount of light that enters as light increases.

Then to reduce the light even further, your cat may close her eyes half way and squint. We sometimes mistake this look on our cat’s faces thinking the cat is either sleepy or disgusted with something or us. This may be true, but it could also be that great adaptation at work, to protect your cat’s eyes.


The ability of your cat’s pupil to change from being a narrow slit in bright light to fully dilated  in low light large equates to about a 300 fold increase in the area of the pupil. Our round pupils only achieve a 15 fold increase.

Those wide open pupils gives them a huge advantage when hunting at night, allowing the maximum light in to see that tiny rodent in the grass.  The vertical slit however also gives cats an edge when hunting as it is believed that it allows them to better estimate their prey’s distance and focus more accurately on their target.

You’ve heard the expression that we apply to people – “the eyes are the window to a person’s soul.”  In your pet cat, the eyes are an indication of their mood and feelings. Start paying attention to the size of your cat’s pupils to get an idea of the state of their mind. You do need to take into consideration the context of what is happening at the time, and your cat’s overall body language as this affects what their eyes may mean.

Generally, a medium sized vertical slit usually indicates a confident, relaxed, happy cat.

The more open or dilated the pupils are at certain times, can mean your cat is feeling  defensive, may be agitated, and the eyes can warn you that they are about to jump away or may scratch or bite.  But as you can see in the photo below, this cat’s eyes are large but it is probably having a good time. Who doesn’t love sitting in a box?

If you notice that your cat’s pupils are becoming larger and rounder in bright light conditions, this can be an indication that something is bothering them. Pupil size is linked to the fight/flight response. If your cat is feeling fearful or threatened, the pupils get larger, letting in more light so your cat can see better, take in more information about the environment, assess any dangers and prepare to escape if needed.

Worried looking cat. Notice the ears – back and somewhat flattened.

A cat that is in pain, can also have dilated pupils. Vets learn to watch cat’s eyes for indications of how they are feeling during examinations.

Also pay attention to how they are using their eyes. If one cat is directly, continually staring at another cat, this can communicate a challenge. On the other hand, if your cat is avoiding eye contact with the other cat, he may be trying to reduce the likelihood of a confrontation.

You may have heard that one way a cat expresses its affection to you is to give a slow blink in your direction – sometimes called the cat kiss. It does seem true that blinking slowly is a sign of contentment and relaxation for domestic felines. Watch for this blink and you can participate in a bit of cat talk, and communicate your own happiness by slowly blinking back to your cat.

Speaking of cats, why do dogs seem to love eating their poop? Maybe your dog has too discerning of a palate to stoop down to the level of a litter box for a snack, but many dogs do covet cat turds as a particularly delicious treat. Why?  More importantly, is there something you can do to stop it? Answers are in episode 52 of Raising Your Paws podcast.

Full Show Notes for Raising Your Paws Podcast Episode 52.

Title: Why Dogs Eat Cat Poop & How to Stop the Dog From Barking at the Mail Carrier.

Do you have both dogs and cats at home? Does your dog eat your cat’s poop? Seems that many dogs find those little turds, a tempting treat. I’ll talk about the habit of eating feces, called coprophagia and how to keep your dog out of the cat’s litter box.

Have you wondered if there is anything you can do to prevent your dog from barking and going ballistic every time the mail carrier shows up at the house? Hear what Katie K-9, a long time dog trainer who I’ve had on the show a number of times before, has to say about how to change your dog’s behavior without using punishment or a shock collar.

You may know that there are numerous ways in which a dog positively affects your physical health, but there is a brand new worldwide study that was just released, (Oct. 2019) in the American Heart Association journal, “Circulation,” that finds that having a dog actually causes pet owners to live longer. I’ll explain all the exciting and comforting details.

Win a free large bag of NutriSource pet food and help us out – by offering your feedback about the podcast. Write me at either susan@raisingyourpaws.com or leave a comment in the section at the end of the blog article for episode 52 at our website, www.raisingyourpaws.com. We’ll randomly select three people to win a bag of dog food and three to win a bag of cat food.

Additional Resources for the show.

Source for story about dogs eating cat poop. “ComPETability: Solving Behavior Problems in your CAT-DOG Household” by Amy Shojai.

Katie K-9 Website – to hear radio show and podcast.

Source for story about dog owners living longer.