Why do cats eyes glow?

For thousands of years, the light of cat’s eyes has led people to thoughts of the supernatural. So why do cats’ eyes glow? Perhaps the joke about cats’ X-ray vision is quite witty, but there are several real scientific reasons for the glow in cat eyes.

How and why a cat’s eyes glow

Cats’ eyes glow because light that hits the retina is reflected off a special layer of the eye membrane. It’s called tapetum lucidum, which is Latin for “radiant layer,” explains Cat Health. The tapetum is a layer of reflective cells that captures light and reflects it back onto the cat’s retina, giving the appearance of a glow. ScienceDirect notes that the color of such a glow can have different shades, including blue, green or yellow. Therefore, sometimes you can even notice that the cat’s eyes glow red.

Survival Skills

Glow in the dark eyes of a cat are not only for beauty, they serve a specific purpose. Tapetum increases the ability to see in low light, explains the American Veterinarian. This, combined with more rods in the retina, allows pets to notice subtle changes in light and movement, helping them hunt in the dark.

Cats are crepuscular animals, meaning they hunt in dim light most of the time. This is where glowing eyes come in handy: they act as tiny flashlights, helping cats navigate in the shadows and detect prey and predators. The fluffy beauty may be all about cuddling with her owner all day, but like her big feline relatives in the wild, she’s a born hunter.

Cat’s eyes compared to human’s

Due to the structure of the cat’s eye, which includes the tapetum, night vision in cats is better than in humans. However, they are unable to distinguish sharp lines and angles – they see everything a little blurry.

Glowing cat eyes are very productive. According to the Cummings School of Veterinary Medicine at Tufts University, “cats require only 1/6th of the light level and use twice as much available light as humans.”

Another amazing advantage cats have over humans is that they can use their muscles to control the amount of light that enters their eyes. When a cat’s iris detects excess light, it turns the pupils into slits to absorb less light, the Merck Veterinary Manual explains. This muscle control also allows them to dilate their pupils when needed. This increases the field of view and helps to orient in space. You can also notice that the pupils of the cat dilate when it is about to attack.

Do not be afraid and think the next time why cats have glowing eyes at night – she is just trying to get a better look at her beloved owner.