Why Do Cats Have A Third Eyelid?

Our cats are pretty intriguing little beings. From the tips of their fuzzy tails to those twitchy whiskers, the feline anatomy is truly a fascinating thing. When it comes to our cats’ eyes, you may have noticed that they have a membrane layer in the corner of their eyes near their nose. This third eyelid actually serves a purpose—just like everything on our cat’s body does. If you’ve ever wondered why it is that cats have a third eyelid, well, just keep reading, because I’m here to tell you!

Here’s why cats have that third eyelid…

why do cats have a third eyelid

Protection against prey and foreign objects

Cats are fierce hunters, but obviously, our feline friends don’t have to concern themselves with fetching their own dinner out in the wild. That’s what they have us for! That third eyelid that our cats have is said to protect their large and sensitive eyes from being scratched when they capture prey. In proportion to their size, cats have a relatively large cornea, and their genetic makeup serves to protect those large and lovely peepers of theirs with their third eyelid.

Your feline friend cannot see things well up close, and as they hunt and navigate through the tall grass, that third eyelid (AKA palpebra tertia) can protect their eyes should they brush against something which they didn’t clearly see.

why do cats have a third eyelid?

A medical mystery? Well, maybe. But probably not…

Cats are mysterious little beings, and some medical professionals argue that their third eyelid is somewhat of a mystery, too. So much so, that some medical professionals compare a cat’s third eyelid to wisdom teeth or the appendix in humans. Is it really necessary? Well, the jury is still out on that one. But, a veterinarian at the University of Wisconsin-Madison, Paul Miller, says that “the third eyelid of cats plays an important role in maintaining the health of their eye surface.” So, just think of it as that special layer of extra protection. In fact, many species of mammals and even birds have a third eyelid. It’s a natural thing and much-needed extra protection. Interestingly enough, humans and primates are among the only mammals which do not have a third eyelid.

Are you curious about how cats see the world and how their vision compares to ours? Check out this article here on cattitudedaily.com.

What to watch for with your cat’s third eyelid

When it comes to our cat’s third eyelid, there are a few important abnormal findings we watch for which can indicate something is amiss with our cat’s health. A cat’s eyes are very sensitive, and it’s up to us as their owners to know what to watch for to get them the medical attention they need quickly.  These include:

  • Any yellow discoloration (indication of jaundice)
  • Discharge which is accumulating in this pocket

VCA Hospitals tells us that, 

“Cats have a third eyelid, or nictitating membrane, in the inner corner of the eye, which is also covered by conjunctiva. In healthy cats, the conjunctiva of the eyelids is not readily visible and has a pale, pink color. When conjunctivitis occurs, the conjunctival membranes become red and swollen. Conjunctivitis can affect one (unilateral) or both (bilateral) eyes.”

Did you learn anything new and interesting about our feline friends? Don’t forget to share this article with other cat lovers that you know so that they can learn something, too.

Have you ever wondered why it is that most cats have green eyes? The answer is pretty interesting—learn all about it here on cattitudedaily.com!

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