Can Cats See in the Dark?

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By Madeline Wahl, Reader's Digest

If you're lucky enough to have a cat, then you're well acquainted with standard cat behavior, and you've definitely wondered: can cats see in the dark? Many kitties have a very busy schedule, spending most of the day sleeping (Why do cats sleep so much?!), only getting up to check their food bowl or find a new sunbeam to nap in. Sometimes they find time to make some biscuits—this is of course why cats knead—or cuddle with you for a while, leaving you to ponder the question: why do cats purr?

However, that sweet, snoozy cat is gone come nighttime. Suddenly, your feline friend is stalking moths, leaping up on top of doors, and generally causing havoc, even after you've turned out the lights. As you lie in bed listening to your cat scamper up and down the halls, you might wonder exactly how that kitty night vision works.

Read More: 4 Reasons Cats Slap Each Other

Can cats see in the dark?

While many people assume that cats are nocturnal, they're actually crepuscular, meaning that they're most active at dawn and dusk. That's important because even though cats have much better night vision than we do, they do need a small amount of light to see in the dark. So if you're planning to go spelunking with your feline friend, know that cats can't see in absolute darkness any more than we can. However, they can see very well in low light.

"Cats only need about one-sixth of the amount of light that humans do to see in low light situations, but like dogs, they are unable to see in complete darkness," explains Dr. Katy Nelson, senior veterinarian at Chewy. "Also, like dogs, they have many more cones in their eyes, as well as a tapetum, so their ability to process light is far superior to that of humans." Cats don't just have good vision, they're also great communicators. Do you know why cats meow?

What do cats see when it's dark?

However, even though cats are able to see with less light than people, doesn't mean that what they're seeing in the darkness is clearer. "The other unique factor about cats’ eyes is their curved cornea, vertical pupil, and large lens," says Dr. Nelson. "Their vertical pupils can expand up to 135-300 times (as compared to only 15 times in humans) in low light, or when they’re stimulated or feeling playful."

So that's why your kitty's eyes get so big when you grab the feather wand! Dr. Nelson adds, "This allows them to see better in a darker atmosphere, but things do appear blurrier with the pupil expansion."

A cat's eye view

If you wear glasses or contact lenses, you know all about the bother of vision problems. Well, turns out cats have them too: they're near-sighted, meaning they can't see far-away objects very clearly. In fact, our human eyes can see an object in the same amount of detail as a cat would see up close, from up to five times further away.

However, even though cats are near-sighted, their peripheral vision of 200 degrees is wider than that of a person's, which is 180 degrees; perfect for catching that mouse scurrying past in the corner of their eye.

Why do cats have slit-shaped pupils?

That distinctive cat-eye might be a fashion inspiration, but it's incredibly useful for a cat's primary purpose: hunting. "The slit-shaped pupil, with its incredible light control, is how a cat can hunt in near-darkness, and also in bright daylight," says Dr. Nelson.

"In a study from UC Berkeley, the slit-shaped pupil was most often found in animals that hunt by day and by night, and especially among predators that ambush their prey—including cats, snakes, and crocodiles. Those that chase down their prey, like cheetahs and wolves, tended to have circular pupils." So cats can be active during the day, who knew? Find out what other cat myths your cat has been keeping from you.

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How does pupil shape affect cats' vision?

But how exactly do cats' eyes help them ambush their prey? They can't be more useful than that cute wiggle. "To pounce on a mouse, a cat must be incredibly precise when judging distance, and that’s where a slit-shaped pupil can help. The brain takes the images received from the left and right eyes and compares them to help estimate distance," says. Dr. Nelson.

"A cat’s slit-shaped pupil allows them to have both the small pupil and large pupil at the same time by making the pupil small horizontally and tall vertically—a truly incredible adaptation," explains Dr. Nelson. "Tiny pupils deliver the sharpest image and perform best for this process called 'stereopsis.'"

So, if you're heading out for the night and looking to save on electricity, it's okay to leave your cat in the dark as long as the curtains are open—most urban and suburban areas have enough light pollution that your cat will be able to see. However, leaving a light on won't hurt them, and will help you to not trip over them when you get home!

Now that you know how cats see in the dark, find out if cats can see color, too.

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