Why do cats eyes glow?

The stunning sparkle of your cat’s eyes peering out of the darkness may seem like a magic trick to your eyes, but this glow is just a little aspect of feline nature. Your cat’s eyes have some unique morphological and physiological structures that people don’t.

Shining cat’s eyes preserve supernatural thoughts for thousands of years, but why do cat’s eyes glow? While it may be fun/joke to assume that your cat has an X-ray vision, there are some real scientific reasons behind the glow in their eyes.

How and why do cat’s eyes glow?

The cat’s glowing eyes are caused by one particular type of layer present in cat eyes with specific cells known as tapetum lucidum. It is a Latin word for “shiny layer”. The tapetum is a layer of reflective cells that means the light bounces off to this layer and reflects the cat’s retina. It creates a glowing appearance which comes in different colours, including blue, green or yellow.

Cat’s Eyes are made for low-light vision

Cats’ eyes are not similar to ours; there are significant differences in both species, especially in term of anatomical features. Cat’s eyes are made to look with high accuracy in low-light vision.

Tapetum lucidum (also called tapetum cellulosum) in the present in both cats and dogs. The Tapetum lucidum acts like a mirror, allowing light to enter the retina, giving the retina rods and cones another chance to absorb the amount of light available in the morning and evening and at night.

The cat’s tapetum lucidum reflects 130 times more light than human eyes. These rectangular cells that makeup cat’s eye contain large amounts of riboflavin (vitamin B2), and zinc which usually cause a “glow” in your adult cat’s eyes that turn yellowish-green.

Rods play a significant role in cat glowing eyes

Another critical factor that plays a vital role in cat vision, especially in low light conditions, is rod photoreceptor cells’ concentration in their retina. Their retina has six to eight times more rods photoreceptor cell than humans. These rods are way more sensitive to light and movement. However, the human retina has ten times more cone photoreceptors, i.e., light receptor cells that work best in bright light than the cat retina. Cones photoreceptor cells are also responsible for colour vision.

Larger cornea and pupil size

Lastly, because they have larger corneas and pupils in their eyes which allows more light to enter in their eyes and reflect, leading towards the glowing phenomenon, cats cornea and pupil is 50% larger than humans, so their eyes work better in a dim light environment and glows more at night.

When the cat’s eyes glow?

When the lights are dim, you will see your cat’s shining eyes, but they will not glow properly if the room is not dark. This is because the tapetum lucidum needs at least some light to reflect; otherwise, these cells cannot do their job.

Mutated cat breeds affect brighter eyes.

Most cats have green eyes, but some have different colours. Siamese cat owners sometimes notice that their normal pet’s eyes glow bright yellow while genetically mutated Siamese cats have eyes that are not as bright as the normal cats. Even progeny of the same breed’s cats can lose their glow if they have different eye colours/pigmentation.

There are different types of tapetum lucidum in other cat species, giving different colours, including pink and blue and green or yellow.

Glowing eyes help cats survival in the dark

But the shining cat’s eyes don’t just look cool – they serve a purpose. Most world-renowned veterinarian, agree on that that tapetum lucidum enhances retinal illumination in low light. This, combined with the rods in their eyes, change cats’ light and movement, ultimately hunting or providing better survival.

Felines are crepuscular animals, meaning they prey mostly at night or dawn or dusk. This is what happens when bright eyes come in handy. They act like small flashlights, helping cats move around in the shadows and distinguish between prey and predators. Your cat maybe your favourite furry companion, but they are also predators like their big cat cousins ​​in the wild.

Major Concerns

In general, your cat’s tapetum lucidum is well protected behind the retina, so you don’t have to worry about them much. However, a deficiency of the amino acids usually B2 or taurine (found in meat and fish) can lead to harmful tapetum lucidum. Most commercial cat food contains a fair amount of taurine to prevent such deficiencies, but if you prepare your cat food at home, you need to keep checking your eye’s health. You may need to consult a professional veterinarian to make sure the right amount of taurine is included in your home-cooked diet

Cats are near-sighted

While the cat’s night vision is better than ours, they are also near-sighted creatures and can’t pay close attention to distant objects. Humans can be up to 5-6x further away to see something in the same aspect as a cat would see up close. Although the cat’s vision is more blurred, it has a wide field of view of 200 degrees (human eye field view is 180 degrees) for better peripheral vision. They are also good at picking the slightest movements and minimal changes in light

Their pupils expand to absorb as much light as possible

You may have often think why your cat’s eyes are mostly straight during the day, while at night, they expand or expand only when they are in playing mode.

When their pupils have vertical slits, they can focus on an object clearly because different amounts of light can enter the eye via other areas. SO, to focus or get a clearer image they expand their pupil wide

According to University of California study in 2015, when cat pupils expand fully, they allow more light to enter into the eye. This means they can see in deficient light conditions, but it blurs their vision. Also, cats can experience a 125 to 320-fold change, while humans only experience a fifteen-fold difference in this area. This means that the cat can adjust its eyes to see a higher level of light than humans.

What colour are the eyes of cats when light falls on them in the dark?

Usually, cat eyes glow in yellowish-green to bright yellow colour in the dark. This yellow glare may seem strange, but its “brightness of the eyes” symbolizes its distinct benefit to humans in low-light areas.

Tip: Remember the actual colour of your cat’s eyes does not change while glowing.

What is the reason for the “Red eye”?

Animal eyes that are deficient in tapetum lucidum also reflect light. The “red-eye” that appears in flash photography, usually when you are trying to preserve memories of emotional family moments, is a reflection of light from blood vessels present in the human retina.

Blue-eyed cats

Blue-eyed cats, whether Siamese or white-coated, are generally deficient in tapetum lucidum. Like humans, their eyes have a red-eye effect. Some Siamese cats have eyes that seem to reflect yellow light, but they are the only breed that lacks a tapetum lucidum in most members.

Can cats see in the complete dark?

The short answer is, No. While it is widely believed that cats have their own built-in night vision goggles, but that’s not correct, they need at least some level of light to see.

However, they only need 1/6 of the amount of light humans do and can see clearly in very little light.

Cats will not be able to see in the dark, in the rare event that the light goes off at all, but their vision is far more progressive and advanced than the human because of their nocturnal nature.

Which Animals Have YELLOW Eyes At Night?

Besides cats, there is only one animal on this planet with yellow eyes at night, and that is Bear. In the daytime, they usually have dark brownish eyes. But when the light reflects in the dark, they typically appear yellowish-green to bright yellow

Which Animals Have GREEN Eyes At Night?

Cats, dogs, foxes and opossums eyes reflect green light in the low light areas.

Which Animals Have WHITE Eyes At Night?

Coyotes, deers and tigers reflect white light from their eyes at night.

Why Do Animals Have Better Night Sight?

In addition to Tapetum Lucidum

  • More light sensors
  • They have bigger eyes
  • They can see UV and infrared light
  • Other animals with reflective eyes (Tapetum Lucidum) include:

    • Goats
    • Rats
    • Skunks
    • Horses
    • Camels
    • Pigs
    • Squirrels
    • Lemur
    • Walleyes
    • Spiders
    • Ferrets
    • Cows
    • Flashlight Fish
    • Kangaroos

    Conclusion:

    Cat eyes glow at night or in low light areas due to a specific memberane present in their eyes known as tapetum lucidum which reflect light in the dark and due to this cat eyes shine. This highly reflective layer is located behind the cat’s retina and is very sensitive to light.

    The fact that your cat has tapetum lucidum in each eye is because it is a nocturnal creature. This unique cell layer improves its night vision by reflecting less light into the eye’s light-collecting area, giving your cat’s eye a second chance to collect it and send a visual signal to the brain. This is the reason why cats can still make their way through a dark room when you can’t see anything.

    Also, cats have more rods cells in their beautiful eyes, which allows them to see much more clearly than humans. These rod cells in cat eyes also facilitate its greenish-yellow glow at night.

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