Your guide to how and why cats blink
If you’re a cat owner, you may have seen your cat slowly blinking at you from across the room. But what exactly does this gesture mean? And why do cats blink at all?
Clinical Animal Behaviourist Daniel Warren-Cummings explains what’s going on when cats blink their eyes.
Can cats blink?
Cats can blink, and they blink a lot like we do. When a cat blinks, their upper and lower eyelids move toward each other, just like in humans. But there’s one fascinating difference. Cats have a third eyelid, known as the nictitating membrane.
What is the third eyelid, and what does it do?
The third eyelid is a thin, pale membrane tucked into the inner corner of a cat’s eye. Unlike the upper and lower eyelids that blink vertically, the third eyelid moves diagonally across the eye. It doesn’t show up with every blink. But it will sweep across the eye when needed to provide an extra layer of protection and lubrication.
This membrane also houses a tear-producing gland. It contributes around one-third of the moisture needed to keep a cat’s eyes healthy. Blinking, whether it involves the third eyelid or not, helps spread these tears evenly across the surface of the eye.
You usually won’t see the third eyelid unless a cat is very sleepy, relaxed or unwell. If it's visible often, it could be a sign of a health issue that needs veterinary attention.
Why do cats blink?
The act of blinking in cats has a few purposes:
- protection. Blinking shields the eye from potential harm like dust, debris or sudden impact
- cleaning. Blinking helps to clean away any dust or debris that does get into the eye
- lubrication. Blinking spreads tears to moisten the eye surface, keeping the eyes healthy
How often do cats blink?
Cats tend to blink less frequently than humans. But this can vary depending on their mood, environment and overall health. They may blink more when tired, relaxed or trying to remove something from their eye.
What is slow blinking?
Slow blinking is a specific kind of blink where a cat gently and deliberately closes their eyes, then opens them again. Many people interpret this as the cat version of a ‘smile’, a sign of comfort, affection or trust.
While it’s a charming idea, it’s important to understand that the scientific evidence behind this is limited. Cats do slow blink around people they’re comfortable with, but they may also do it when stressed.
Why do cats slow blink?
The truth is, we’re not entirely sure why cats slow blink. Some theories include:
- they’re comfortable. Some people believe that slow blinking may have evolved as a non-threatening signal. A way to communicate that they are comfortable with the person they’re with
- they trust you. Some people think slow blinking is a sign of trust. By closing their eyes in your presence, the cat is showing that they trust you not to harm them when they can’t see you
But the evidence is inconclusive. Slow blinking can be a positive sign, but it can also occur in moments of stress. Some cats may even blink when facing off with an unfamiliar, aggressive cat. The context of the slow blink is important for understanding its meaning.
What should I do when my cat slow blinks at me?
The first thing to do is look at their body language. Find out how to read your cat’s body language.
- If your cat has happy, relaxed body language, they are probably slow blinking to show they are comfortable and trust you. You can try slow blinking back at them to show you feel the same way
- If your cat has unhappy, stressed or scared body language, give them some space. Getting close to them and making eye contact is likely to make them more unhappy. Let them be alone and hide away for a while. Find out how to help a stressed cat
Why doesn’t my cat slow blink?
Not all cats slow blink. If your cat doesn’t slow blink at you, there’s nothing to worry about. It doesn’t mean they’re uncomfortable around you or don’t trust you. Cats show affection in lots of different ways. Perhaps your cat prefers rubbing against you, chirping, head-butting, or simply choosing to be near you. Five signs your cat loves you.
When should I be concerned about my cat’s blinking?
If you notice any change in your cat’s eyes or their blinking, speak to your vet. It could be a sign that something is wrong with their eyesight or health. Speak to your vet if you notice:
- excessive blinking
- squinting
- eyes stay completely or partially closed
- the third eyelid is often visible
