The Blinking Mystery: Do Cats Need To Blink?

Cats are known for their staring contests, but they do actually blink. In fact, they blink pretty regularly, just not as often as humans. While humans blink 15-20 times per minute, cats can go for hours without their upper and lower eyelids meeting. This is because cats are predators that can also become prey, so they need to stay vigilant of their surroundings. When a cat does blink, its eyelids don't fully close. Instead, its upper and lower eyelids move towards each other in a partial blink, and its third eyelid, called the nictitating membrane, moves diagonally across the eye. This membrane is thin and translucent, and it's believed that cats can still see during the fraction of a second when it's blinking.

How often do cats blink?

Cats don't blink in the same way humans do. Instead of their upper and lower eyelids meeting, cats have a third eyelid, called a nictitating membrane, that moves rapidly and regularly across the eye to clear debris. This allows cats to benefit from blinking without ever fully closing their eyes.

Cats are both predators and prey, so they need to stay vigilant of their surroundings for threats or prey. Blinking too often or closing their eyes is detrimental to their survival. Therefore, cats don't blink regularly like humans, who blink between 15-20 times per minute. Cats may go for hours without their upper and lower eyelids meeting.

Cats also use blinking to communicate. A slow blink is a sign of trust and relaxation, and a cat may even return a slow blink if you do it first. Conversely, rapid blinking can be a sign of discomfort, fear, or a negative emotional state.

Why do cats have three eyelids?

Cats have three eyelids—an upper and a lower eyelid, and a third eyelid known as the nictitating membrane. This third eyelid is located inside the corner of the eye and closes diagonally across the eyeball when a cat blinks.

The nictitating membrane has several functions. Firstly, it helps to protect the eyeball from potential trauma. For example, when a cat moves through tall grass or captures prey, the third eyelid elevates to prevent the cornea from being scratched. It is believed that the thin membrane may be translucent enough for cats to see through, giving them an advantage when hunting.

Secondly, the nictitating membrane aids in tear production through special glands located within it. This helps to keep the eye moist and clean by removing debris and redistributing tears over the cornea. The membrane acts like a windshield wiper, allowing cats to benefit from blinking without ever fully closing their eyes.

The third eyelid is present in many species, including mammals, birds, reptiles, amphibians, fish, and some other mammals. Humans and some fellow primates are the oddities in nature for lacking a third eyelid. Scientists believe that humans may have once had a third eyelid, but it reduced in size over time due to a lack of advantage. Unlike cats, humans did not need to capture prey by biting or stalking through vegetation face-first.

Why do cats blink slowly?

Cats are known for their staring contests with humans and rarely blink in the same way that humans do. Instead, they have a nictating membrane, also known as a third eyelid, that moves rapidly and regularly across the eye to clear debris. This allows cats to get the benefits of blinking without ever fully closing their eyes.

Cats blink to clear out any small particles or debris, such as dust, and to keep their eyes hydrated. Their third eyelid also extends upwards to protect their eyes from scratches and trauma or in response to inflammation.

But why do cats slow blink? A study by the University of Portsmouth and the University of Sussex found that a cat's slow blink is his way of smiling at you. When a cat closes its eyes around you, it is associated with positive emotions and means that they feel comfortable and safe. If you want to reciprocate the sentiment, you can mimic your cat's slow blink, which is like starting a conversation.

Slow blinking in cats has been shown in studies to occur more frequently as a response to human slow-blinking stimuli. One study found that cats were more likely to approach a person if that person provided a slow-blink stimulus than when they had a neutral expression on their face. Closing the eyes in the presence of another animal (including humans) is considered the ultimate signal of trust and comfort.

Why do cats blink rapidly?

Cats have a third eyelid, called a nictitating membrane, that rapidly and regularly moves across the eye to clear debris. This allows cats to get the benefits of blinking without ever fully closing their eyes.

The nictitating membrane is pink and located in the inside corner of the eye, under the upper and lower eyelids. This membrane is very thin and can move very quickly. When a cat blinks, the upper and lower eyelids move towards each other in a partial blink, and the third eyelid moves diagonally across the eye. This is why sometimes it seems like your cat may be squinting.

Cats blink to clear out any small particles or debris like dust, and to keep their eyes hydrated. Their third eyelid also extends upwards to help protect their eyes from scratches and trauma, or in response to inflammation.

Rapid blinking in cats is often associated with feelings of discomfort or fear. During rapid blinking, the eyes close quickly and the eyelids become closed shut, causing crinkling of the skin on the cat's face. If you're faced with a fast-blinking cat, the best option is to back away and let it cool down.

Why do cats sleep with their eyes open?

Cats are known for their staring contests, and it's true that they don't blink as often as humans. But why is that?

Cats have three eyelids, unlike humans, who only have two. The third eyelid is called the nictitating membrane, and it moves diagonally across the eyeball when a cat blinks. This membrane is translucent and helps to protect the eyeball, restore the tear film, and keep the cat's eyes clean. The nictitating membrane also allows cats to keep their eyes open for longer periods of time, as they don't need to fully close their eyes to get the benefits of blinking. This is especially important for cats as they are both predators and prey, so they need to stay vigilant of their surroundings at all times.

Additionally, cats don't need to blink as frequently as humans because their tears are more viscous and take longer to evaporate. Cat tears are a mixture of water, oil, and mucus created by glands around their eyes, which helps to keep their eyes moist and protected.

So, while cats do sleep with their eyes closed, they can also go for hours without blinking when they are awake, thanks to their nictitating membrane and the composition of their tears.

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