Why do cats blink? And does blinking slowly help with feline communication?

A cat with its eyes closed
(Image credit: Getty Images)

"Why do cats blink?" might not be a question you've ever really given much thought to. After all, you probably understand why people blink – to keep our eyes nice and moist and to clear away any foreign bodies – so it's likely the same thing for cats, right? However, that's not quite the case.

If you're a particularly observant cat-watcher, you might instead wonder if they ever actually blink at all. It's possible to watch a cat for absolutely ages without catching it blinking, so what's going on there? Does it simply not blink, or does it somehow time its blinks to match yours so you never catch it in the act? When you think about it, that's just the sort of fiendish trick a cat might pull to confuse its humans!

Thankfully we're here to dispel as much confusion as we can. Whatever your questions about cats and their blinking, you'll find all of the answers below. And because blinking can also be a kind of cat body language, we'll also talk about what cat blinks can mean, and how you can make use of them as a form of cat communication

Read on to get all the answers you need, or alternatively see our more general guide to cats' eyes for plenty more fascinating feline facts.

A ginger cat with its eyes almost closed

(Image credit: Getty Images)

It's probably safe to say that we've already established that cats blink. However they don't quite do it in the same way that we do. Cats' eyes are largely similar to ours but with some fascinating differences, and one thing they have that we don't is a third, inner eyelid, called the nictitating membrane. When a cat blinks it doesn't fully close its eyelids; instead the upper and lower eyelids almost close, while the nictitating membrane quickly swipes diagonally across the eyeball.

As we've mentioned, we humans blink to keep our eyes in good condition. And cats do it for much the same reason – to clear away dust and debris and to keep their little eyeballs moist. The big difference, however, is that while the tears in our eyes evaporate quickly, which means we tend to blink a lot to stop them drying out, cat tears are more viscous – they're a mixture of water, oil and mucus created by glands around their eyes – so they take a lot longer to evaporate, and that means cats don't need to blink as frequently as we do.

There is of course another reason that cats blink, and that's as a form of communication; we'll come back to that in a bit. But getting back to why your cat might be blinking, if you're noticing excessive blinking or watery eyes, your cat may need medical attention; our article on Why are my cat's eyes watering can give you all the advice you might need.

A cat with its eyes slightly open

(Image credit: Getty Images)

Nowhere near as often as we do. Humans tend to blink between 15-20 times a minute, and as we've already mentioned, it's an essential thing we do automatically to keep our eyes in good condition. Cats, however, can't afford the luxury of shutting their eyes multiple times a minute; they're predators who can also find themselves as prey to bigger animals, so they need to be watchful the whole time.

So they only blink when they need to, and because their eyelids don't fully close when they blink and the translucent nictitating membrane does the business of refreshing their eyeballs, it's thought that they can still see during those fractions of a second when they're blinking.

How long do cats go without blinking?

Cutting to the chase, then, how long exactly can a cat go without blinking? If you've ever wondered whether cats actually blink at all, this will go some way to explaining that train of thought: cats can actually go for hours at a time without what we think of as a blink. They might occasionally refresh their eyes with a lightning-fast swipe of that nictitating membrane, but their eyes will remain open and watchful.

A grey cat with one eye open

(Image credit: Getty Images)

Most cat blinking is all about keeping their eyes in good condition, and while in most cases it's simply regular upkeep, sometimes cats – like us – will get something in one eye, or one eye might get drier than the other one. And while we might blink when we get something in one eye, cats, as we've noted, prefer to see as much as possible at all times. 

And so when your cat is troubled by one eye but the other's fine, it'll simply blink with that eye and keep the other fully open. It might look strange to us, but from the cat's perspective it's the most visually effective way of doing things.

Aside from everyday blinking as a form of eye maintenance, what does it mean when a cat blinks (or even winks) at you? It depends on how quickly it happens.

As most cat owners surely know by now, receiving a slow blink from your cat is a great honor; in cat terms, shutting your eyes for any length of times means that you're feeling comfortable in that situation, and so a slow means that kitty loves you, or is at least happy in your presence. 

However, a cat that's rapidly blinking (or winking) is in quite a different mood; this means that it feels uncomfortable, nervous or frightened. If you're faced by a fast-blinking cat, the best option is to back away and let it cool down for a bit.

Can you communicate with your cat by blinking slowly?

A grey cat with narrowed eyes

(Image credit: Getty Images)

You can indeed. The slow blink is a potent form of cat communication, and if you're in the receiving end of one it's only polite to return the compliment. You don't have to wait to receive a slow blink, though; if you're trying to break the ice with a stand-offish cat, a slow blink – followed by looking away from it for a few seconds – is an excellent way to communicate to it that you're not a threat and you're not treating the cat as a threat, and kitty may well reciprocate the gesture.

Should I avoid direct eye contact with my cat?

As a rule, yes. Cats don't like direct eye contact; staring between cats is generally a sign that they're squaring up for a fight. A cat staring at a human is a little more complex but if your cat's staring at you, you shouldn't really stare back, although if you find you've locked eyes with kitty without thinking, a slow blink will defuse the situation.

Jim McCauley

Jim is a writer, performer and cat-wrangler based in Bath, who last year adopted a pair of sibling rescue cats who turned out to be effectively feral, and has spent a lot of time since then trying to get them accustomed to people (some success) and each other (ongoing project).