Cat Pupils: Here’s What Your Cat’s Eyes Are Telling You

Cat pupils do more than respond to light. Discover how your cat’s pupils are the keys to her mood — and can even tell you if you need to see a vet ASAP.

Angry cat with ears flattened back and wide eyes.
Angry cat with ears flattened back and wide eyes. Photography ©manop1984 | iStock / Getty Images Plus.

A cat’s eyes are pretty amazing. They allow a cat to see in near-darkness and provide her with a great ability to detect motion in order to hunt prey. But the thing that really fascinates a lot of people are those vertical, slit-shaped cat pupils. Cat pupils do much more than respond to the level of light in a room, though. They also give you a good sense of how your cat is feeling — emotionally and physically.

Here are a few cool things to know about cat pupils:

Cat pupils show your cat’s mood

A scared or surprised cat with his back arched and eyes wide.
Cat eyes are the windows to your feline’s soul — and emotions. Photography ©PeopleImages | DigitalVision / Getty.

Our cats communicate with us in very subtle ways, and one of those ways is through their eyes. A cat’s mood can be determined by a combination of understanding cat body language and cat pupils.

Narrow pupils signal an aroused cat

A gray cat with yellow eyes with his mouth open.
Narrow pupils mean your cat is feeling aroused by anger, fear or pleasure. Photography ©graphixchon | Thinkstock.

Arousal can be caused by many things — anger, fear and pleasure, primarily. These emotions can result in the sudden contraction of pupils so that they become narrow slits. You might see this if your cat encounters a catnip mouse and prepares to attack it. Even the smell of catnip itself can cause arousal in a cat that likes the stuff.

You may also see the pupils contract suddenly if she’s about to “kill” her favorite toy (or your toes moving around under the blankets). Anger can also cause pupils to contract into slits; this is usually accompanied by growling or hissing, though.

If the cat eyes are narrow and the eyes are squinted, that’s a sign of aggression. The squint helps to protect her eyes from an opponent’s claws.

However, if the cat pupils are narrow and your cat is relaxing on your lap and purring, you can probably guess that she’s experiencing great pleasure.

Wide pupils signal an excited or scared cat

A ginger cat with large, wide eyes.
Large cat eyes signify two emotional extremes — excitement or fear. Photography ©aluxum | iStock / Getty Images Plus.

Yes, it’s true: wide cat eyes can mean both excitement and fear, so you’ll have to suss out the meaning of your cat’s wide eyes by looking at what’s going on around her and her other body language cues. For example, when my cat, Bella, gets surprised, her pupils go wide and she jumps up in the air with the classic “bottle brush tail.” Wide cat pupils can also indicate excitement. When you pull out your cat’s favorite treats, her pupils may get wide in anticipation.

On the other hand, wide cat pupils may indicate anxiety. If your cat is sitting there, looking tense (with a hunched back and her tail close to her side), and her pupils are also wide, you can assume that she’s anxious about something. You’ve probably seen this when you take your cat to the vet and she really doesn’t want to be there.

Wide cat eyes can also indicate abject terror. Maybe you’ve seen this if you’ve been in a huge thunderstorm, just before your cat runs for the smallest and darkest place she can find.

What if the cat pupils are different sizes?

When one of the pupils is larger than the other, your cat has a condition called anisocoria. Anisocoria is a symptom, not a disease itself. Sometimes, it’s an emergency.

“If anisocoria occurs suddenly, you should consider this an emergency situation and seek veterinary care immediately to lessen the chance that your cat’s vision will be permanently affected,” Cheryl Yuill, DVM, MSc, CVH, writes in an article on anisocoria in cats for the VCA.

When pupils are different sizes, it can indicate that your cat is suffering from one of the following issues: a brain injury due to trauma (such as a fall or being hit by a car or a disease like a stroke); an injury to the surface of the eye; a problem with the nerves running to the affected eye; glaucoma, a very painful pressure buildup in the eye; inflammation of the interior of the eye; retinal disease; or even cancer. Cats may also develop anisocoria due to spastic pupil syndrome, which is associated with the feline leukemia virus.

The final word on cat pupils

Cat pupils are an amazingly expressive part of your feline friend’s body language repertoire. By studying your cat’s eyes along with her body language, you’ll be able to understand your cat better and avoid unwanted aggression or fear. The pupils are also a reflection of your cat’s health. Don’t hesitate to get your cat to the vet if you notice that her pupils are different sizes.

Tell us: Have you noticed your cat’s pupils changing different shapes and sizes?

Thumbnail: Photography ©manop1984 | iStock / Getty Images Plus. 

This piece was originally published in 2018. 

Read more about cat eyes on

Read more about cat body language on

69 thoughts on “Cat Pupils: Here’s What Your Cat’s Eyes Are Telling You”

  1. Our newly adopted 8yr old black cat has blue eyes green outer ring she never opens them wide they are always squinting when we toss a toy or treat she never tracks it, is there a problem?

    1. What about the cat's body action? Is he facing towards you, or away? Is the tail curled, or lying flat against the floor?

      Depending on these points, "meow" could mean "let's watch a movie together" or "boy am I thirsty right now."

      So getting the tone and body language right is critical!

      Finally there’s a quick guide on the bare essentials of cat communication to give you a starting point into the fascinating world of feline communication, both verbal and nonverbal

      This guide, written by a PhD animal communications expert, will help you learn a few things your cat tries to tell you every day – that you're almost certainly ignoring right now.

      Check it out here: ( ) ( copy link and put it in your browser )

    1. Uh yeah, maybe learn that english isn’t everyone’s *one and only* language and you can easily use google translate if need be

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  5. I was noticing in photos of large, wild cats, their pupils are round — why are domestic cats’ pupils oval/”slit shaped”?

  6. Lorenza Marrujo

    I have a 17 yrs old cat, that l worry very dearly, she’s been with me since l found her under the bushes one day coming home from the bus stop, she’s still with me, but l worry about her soo much now that’s she older, l love her dearly and don’t want to lose her, her name is “Kiki”, she’s my Queen, although l have 4 other cats, (2 males/2 femles) that are not fixed yet, “Kiki”. is fixed though, but,l too wonder about her eyes and health, l worry about all my babies for that fact. “Kiki” needs to see the vet very soon, l just pray that she’s in good health.

  7. Why is my cat throwing up . it happens after he eats . its cat food not puke no blood. Nothing else other than the food. He can drink with no problem . he uses his litter box . please can you help me n if i need to take him to my vet

    1. Heidi Christensen

      You NEED not to just take them to a vet but to GET THEM FIXED! Every heat the female cat goes through make that much more chance of getting mammary cancer. Trust me – I know!

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  9. Usually when Lucy’s eyes are dilated where they look almost completely black….WATCH OUT! She is in attack mode. Myself and friends better leave her alone. Hopefully she will attack her toys or a chair that has been clawed by previous cats. When her pupils are somewhat dilated she thinks she’s a dog and wants to play fetch. With a cat toy, a piece of string, a hair tie or a bobbiepin. When she gets tired she lays on it to hide it and takes a long nap. Then I’m not sure what her pupils look like cause her eyes are closed!

  10. My little calico rescue will sit patiently with pupils roundish and stare at me. This occurs in the evening. If it is around 10 pm she wants me to go to bed. Earlier, she wants a snack.

    1. My rescue calico does the same thing. She is 15 yrs old now and has been deaf for over a year. She communicates with me by yowling. This occurs after naps (telling me )she is awake, wanting her daily snack and sitting by a toy wanting me to play with her. She is my Blessed companion.

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  16. Why all cats are female? Why you just say she’s or her and why you don’t say he’s or his/him? Are you stupid? Are you didn’t know a cat’s gender? you’re wrong. she’s it’s me . Because i’m a girl. This cats are boy and girl. That’s mean he and she her and his/him. Not only she’s or her . I’m a girl and she’s or her it’s me . You’re wrong. Sorry that I entered in other topic.

    1. A cat’s pupils react to light and darkness. If the room is very sun lit, the cat’s pupils will be narrow slits, and when room is darker, the pupil is very wide. Never heard of mood changing size of a cat’s pupils. Even humans pupils react to light in the same way.

      1. Have you never noticed when a cat is about to pounce on something their eyes go very big. Their eyes definitely do change not only with light and dark but with things going on around them. What a cats eyes next time you go to play with a toy with them or when they are about to run round like a crazy cat which is so funny to watch

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  19. You left out that you should also take your cat to the vet right away if you notice that his or her pupils are dialated all the time. In my cat’s case, it meant she had encephalitis.

    1. Hi just stumbled across this site..he had my cat to vet as I thought she was going blind shes nearly 9yrs. She had usual tests blood pressure, diabetes, blood tests. Results blood pressure ok, not got diabetes/glaucoma which vet says could be treated if that was the cause. Vet says pupils do react slightly, but when she put her hand right in front of cats face she never moved. She confirmed she is blind suggested referring to Cat Opthalmologist for further tests…costly but may confirm actual reason as vet doesnt know.
      Should I have let her refer me. The cats blind and that’s that! Its upset us all.

      1. If the cat is blind now I do not think throwing money on an ophthalmologist is going to help. You might be better off spending your money on someone to teach you how to make life easier for your cat. Incidently what was happening with your cat to decide to take it to the vet. My neighbours cat who comes to visit me I have noticed the black part of his eyes are big all the time now and one pupil looks bigger than the other that’s why I got on here to find out what it could possibly mean before I speak with the neighbour

        1. Hi. My cat has a smaller pupil in the left eye. A few nights ago this eye was red and the pupil was much smaller. The redness quickly disappeared the same night and the pupil got a bit larger. But until this time, it is still not as big as the other one. My cat is not showing any discomfort. No swelling was observed or any bleeding at all. She looks unbothered by it but I am still worried. What should I do?

          1. You should at least have the eye checked out by a vet. There are a lot of cats with one pupil larger than the other, the reason is usually lack of oxygen at birth causing a little brain damage.

  20. your post is very interesting to’s very informative and helpful.
    Usually, I never comment on blogs but your article is so convincing that I never stop myself to say something about it. You’re doing a great job, Keep it up.

  21. Cats are just remarkable creatures!
    Wide eyed, ears up mouth open surprised looks when they get caught misbehaving make me laugh out loud.
    I love the relaxed, half closed eyes when my cats cuddle with me. I know they are content!

  22. It seems with my cats, the angrier they are the smaller the pupils. If they want to play or are relaxed, their pupils get large, especially when playing with catnip.
    I do love getting the surprised cat face with wide eyes, open mouth and ears up. We rarely have bottle brush tails around here which I think is good.
    I also love the relaxed, half closed eyes of my cats when they are cuddling with me. I know they are happy!
    Cats are just remarkable creatures!

  23. My larger cat gets jealous when I pay too much attention to the small cat. His pupils get huge, so that his eyes go black, and he starts chasing and hitting the small one.

    1. Hi MAG,

      Thanks for reaching out. We suggest working with your vet or a professional behaviorist on this. These articles might provide some insight as well:

  24. The whole section on pupils that are narrowed into slits, seems wrong for my cat; my Annie’s pupils get huge whenever she hisses, is fearful or distressed or angry! Strange that it’s the opposite to what this article says.

    1. What’s written here doesn’t agree with my cat’s behavior, either. Her pupils get huge when she’s in hunting mode, and ready to pounce on her favorite toy. Very little of this article made sense to me.

  25. Holisticritters

    That type of behavior and physical symptoms can also be caused by a number of things, including seizures, which is also a symptom most of the time of an underlying disease. one has to consider the body as a whole, rather than a symptom as a disease. Thanks for sharing that one! So glad your little one is okay!

  26. Michelle Westermeyer

    I have a Maine Coon Cat named Bear. He follows me into the bathroom every morning and is wanting to be fed. He talks to me the entire time he is with me. I have noticed for the last several years, he is 10 yrs old, that when he is talking to me his pupils cover his entire eye. He looks so cute but I never noticed it in my other Bengal tiger Kitty who is also 10 yrs old. Bear has always talked a lot since he was a kitten. He and Sasha are rescue babies I got 10 yrs ago. He likes attention but doesn’t want anyone close enough to touch him. He is a very silly boy. He can carry on a great conversation, but his pupils are open just as wide as they go. He’s not mad or anxious.

    1. I have a half Maine Coon, half Russian Blue that is very vocal as well.
      So are my tabby cat that have tortious shell swirl patterns. They have what I call tortitude. That’s tortious shell attitude!

  27. Nancy P…I am so sorry for your baby…
    We are still sad about one of OUR cats: 4 years ago, our black Siamese started having minor strokes (hubby called them ‘spells’); our vet SWORE he was in no pain..just a little confused. hard to check his pupils because his eyes blended in with the REST of his face so well. After his last couple “spells” I could tell his end was near..was like he didn’t know HOW to “cat” anymore..his last day his pupils dialated (?? spread out to cover the whole visible surface)..he could no longer see anything..that was the day we couldn’t let it continue.

    1. not true that anyone owning a cat ‘knows’ these things…. getting helpful tips and helps is great please keep sharing them and for those who already know great do not hinder the sharing for the rest of the people.

      1. Thank you for this response.
        Not everyone here is a veteran cat owner and even we veterans can learn something new!
        This is a great place for new owners to get information and veterans to brush up in the facts. New discoveries are being made everyday especially in feline medicine. Saying that everyone who owns a cat knows this or that just isn’t true!

      2. I agree with you ! My cat is 16 now and i do not know many of these signs. My cat pupils are very large and need to know why before i go to the vet. Also she is eating less and drinking a lot of water. Any good info would help please ? Thank you

  28. When our older calico suddenly went to full black pupils in both eyes (a tiny sliver of color around the black, but as full as I’ve ever seen in a cat), I asked a vet online since it was late on a Sunday night. Then the next morning the calico also started tripping over things. Turns out her kidneys had failed and she was 100% blind. It happened so fast. We called our vet on Monday morning and got her in, only to find out that she needed to be put to sleep. There was no saving her at that point. (Prior to that we’d been going in for weekly sub-q fluid to help her kidneys, and laser therapy for pain.)
    So that’s one more thing that a cat’s eyes will tell you.

    1. We went through this as well…I had no idea what to look for…sending you a soft hug. And wishing your baby and mine ann eternal resting place full of everything they always wanted.

  29. When my cat fell off a table and her eyes were spinning,the vet diagnosed it as a seizure due to possible poisoning. He prescribed force-feeding tokeepher alive! After a week (in which she gainedweight), she became incontinent & I had her euthanized (by another vet).
    Sure wish I had hadyour good advise.

  30. When my cat had toxoplasmosis, his pupils were different sizes. His eyes looking “off” (one was normal and the other looked almost cloudy/dull; the pupils changed sizes later) and him acting lethargic is what prompted me to call my vet. I’m very thankful it was toxo and not feline leukemia, which is what the vet was afraid of at first. He’s fine now after two looooong rounds of antibiotics.

  31. My 19-year-old kitty has had dilated pupils for approximately the past year. His vision still seems to be good. But the pupils never retract to their normal size. What could be causing this?

    1. My 13 year old also has this issue, but it doesn’t seem to affect her sight, and she’s still active. Could it simply be that she’s getting older?

  32. If your cat ever falls off a windowsill or couch or bed and starts to walk as if drunk or in circles and it’s pupils are rotating side to side as mine did…..and one pupil seems larger Than the other grab him quickly in his cage and get him/ her to a vet a.s.a.p. that is Feline Vestibular disorder it’s a deep inner ear infection That can cause either a permanent or non permanent head tilt I went thru that with my girl took 2 months to heal luckily her head finally went straight….but yes always check the eyes and GOD BLESS Dr.Melissa Toulouse From the A.S.P.C.A. of Manhattan ….She is the very BEST! Also Dr.Stewart a Very Very Good Knowledgeable man in his field . They have a Great team love you guys Stacy XOXO!

    1. Why all cats are female? Why you just say she’s or her and why you don’t say he’s or his/him? Are you stupid? Are you didn’t know a cat’s gender? you’re wrong. she’s it’s me . Because i’m a girl. This cats are boy and girl. That’s mean he and she her and his/him. Not only she’s or her . I’m a girl and she’s or her it’s me . You’re wrong. Sorry that I entered in other topic.

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