Many beliefs surround cats and their abilities and powers. Some of them were true, like their tendency to offer their master animals from their hunt. While some of them are pure myths, like black cats, often associated with bad luck, and have been for centuries in many cultures.
A common belief about felines has to do with their vision – and, in particular, their ability to see in the dark. Many cat owners believe that their pets have extremely well developed night vision and are able to see as well in the dark at 2 a.m. as in the daytime at 2 p.m.
But is it true? Can cats really see in the dark? And if so, how does a cat see at night? In this article, I tell you everything you need to know about night vision in cats.
How does a cat see detail at night ?
Let’s cut to the chase: can cats see in the dark?
It turns out they can – at least much better than us humans. Cats have the ability to pick up more details in the dark than humans, This means that in the dark when we look around and can barely make out the structure of our bed moments before we get there install, cats can very easily see shape, texture and other finer details that are invisible to us in the dark.
So cats don’t see as clearly at night as they do during the day, but they can pick up details much better than we can when it’s dark.
Why do cats see in the dark?
Regarding all species, the level of vision is never the same between each animal and is sometimes totally different. For example, the mantis shrimp has more color receptors than humans (12 against 3) , allowing them to see a range of colors that we can’t even begin to imagine. Eagles can see four to five times farther than humans (hence the term « eagle eye »). And, as we’ll see here, while humans are blinded by darkness, cats have a much easier time seeing in the dark than we do and can live in it much more easily.
But why do cats see so much better than us when it’s dark?
There are a number of reasons why cats have better night vision than us, and most of them have to do with their eye structure. Here are the reasons why cats can see in the dark much better than us.
1. Pupil shape
Most animals are like us at this level, having circular pupils. But cats’ pupils have an elliptical, slit-like shape that plays an important role in how well they can see in the dark. Elliptical pupils compared to our circular pupils, can bring more light into their eyes in the dark. Cats’ pupils also dilate significantly to allow the most amount of light to enter during the night… Cats can enlarge their pupils 135 times, compared to only 15 times for humans.
It is thanks to this vertical pupil that cats can see so much at night, but without being completely blinded during the day.
2. Photoreceptors and rod to cone ratio
All retinas (humans, dogs, cats and others) contain two different types of photoreceptors: rods and cones. Each receptor has a different function in the eye; the rods are responsible for night vision and peripheral vision, while the cones are responsible for day vision and color processing.
The human retina contains approximately 120 million rod cells. But cat retinas contain between six and eight times the amount of rod cells – which is one of the reasons they see so well in the dark.
Cats have a high rod count and a low cone count, the exact opposite of what we have as humans.
3. Corneal size
The cornea is the outermost layer of the eye. When light enters the eye, it is bent by the curved edge of the cornea, which plays an important role in the eye’s ability to focus on objects.
Cats have a relatively larger corneal size than humans. It is a key component of their ability to see in the dark. Cat corneas take up more surface area, which means their eyeballs are bigger than ours at their size. Larger corneas mean a larger light entry surface.
The more light in the eyes, the easier it is for cats to see and focus, even in what we humans perceive as darkness.
4. Tapetum lucidum
No, it’s not a spell straight out of Harry Potter. It is an extra layer of tissue behind the retina that cats have. Tapetum lucidum is completely absent in humans but useful in cats. The tapetum of a cat’s eye is the shiny green reflective surface we often see in photographs of cats eyes or when we see cats outdoors at night.
This fabric acts as a retroreflector, reflecting light back into the eye and giving cats an even greater ability to see through the dark.
There are a number of other animals (including deer, dogs, horses, ferrets, and cows) that have tapetum lucidum. But there are also many (including primates, squirrels, kangaroos and pigs) that don’t have it, which probably has to do with how long an animal spends in darkness and, by therefore, how much he needs to see in the dark.
4. UV light vision
Not only do cats see better than humans, but it turns out they can see more than us. Unlike humans, cats have the ability to see UV light, which allows them to see things (like patterns in flowers or streaks of urine to aid in hunting) that are invisible to us.
Where does this superpower come from? A cat’s ocular medium (which is just a scientific term for the transparent parts of the eyes) transmits UV wavelengths, which allows more light to enter the retina. And, as mentioned earlier, more light in the retina means better night vision.
5. Mustaches and ears
As we have seen, cats can see better than humans in the dark. But it’s not just their eyes that make them so adept at moving when the sun goes down.
A cat’s whiskers act as tactile receptors, helping them to get a better sense of their surroundings and detect any potential obstacles, while a cat’s keen sense of hearing allows them to hear higher frequency sounds at a greater distance than humans, which helps them navigate in the dark.
To take an example, let’s say you and your feline friend are both out after dark. You are in total darkness. There is no artificial light, no moonlight, just darkness. You both need to find an animal hiding somewhere in the dark.
While you’d be tripping blindly, your cat would not only be able to see better in the dark, but her ears would allow her to hear even the tiniest rustle of leaves from a much farther distance. Once he heard that rustle, his whiskers would help him navigate the darkness and find the other animal.
Eyes, ears and whiskers – a cat is made to move in the dark, and it will see, hear and move better than us.
Why did cats evolve to see so well in the dark?
Between their vertical pupils, a relatively high number of rods, a large cornea, and the presence of the tapetum lucidum, it’s clear that cat eyes are made for seeing in the dark. But why? How did cats evolve to see so well in the dark?
Most experts believe that cat eyes (and, in particular, a cat’s vertical pupils) evolved to make them better night hunters. Research suggests that vertical pupils are most common in nocturnal animals that use ambush as their primary means of attacking prey. The idea about this is that the shape of the pupil allows for very accurate gauging of distance for catching prey. Ambush predators must be good at judging distance to allow them to jump and catch something moving.
So basically, vertical pupils not only allow your cat to see better in the dark, but they also allow them to get a better sense of where and how far away their prey is, allowing them to sneak up and catch them easier.
But not all felines are equal when it comes to night vision. While domestic cats have vertical pupils, larger felines (like tigers and lions) do not. This may be because cats are not exclusively active in low light situations. For day and night active species, such as house cats, slit pupils provide the dynamic range needed to help them see in dim light without being blinded by the midday sun.
Although vertical pupils definitely help your cat hunt better in the dark, they are not good for low light hunters. And it is worth mentioning: even without vertical pupils, lions have no problem finding their prey, regardless of the hour. They aren’t called « King of the Jungle » for nothing!
Do cats have the best night vision in the animal kingdom?
There’s no denying that cats have an innate ability to see in the dark. But how does it compare to other animals?
Cats have excellent night vision, but not the best compared to other animals. While cats are adept at seeing (and hunting) in the dark, their eyes are no match for some other predators – for example, the owl.
If you think of an owl’s eyes, they are designed to see very well, especially in the dark. They have very large eyes compared to body size in the animal kingdom. Owls also have the ability to pick up UV light very well, even in the dark, so they can follow the urine or faeces of the mouse that left them, in order to find their next meal.
Although cats can definitely stand their ground in the dark, if they hunt the same mouse as an owl, the owl will win every time.
Differences between cat vision and human vision
As mentioned, cats have fewer conical photoreceptors in their eyes. In addition to changing how they see in the dark, it also changes how cats see color. They’re not completely color blind, but they don’t see the vibrancy in the nuances like we can. In 2013, an artist named Nickolay Lamm even went so far as to create renderings of what cat vision looks like compared to humans. The results are fascinating.
There are also differences between cat and human vision when it comes to distance. Cats are nearsighted, so they can see things up close very well, but humans have the ability to see things far more clearly than their feline counterparts.
Thanks to their large corneas, cats also have a wider field of vision. 200 degrees [of vision] versus our 180 degrees. Think of it as constantly walking around with an almost panning camera.
So yes, cats can see in the dark, at least much better than humans. Although they may not have the best night vision in the animal kingdom, they are among the best off. Don’t worry about leaving a light on for your cat when you fall asleep; with their eyes, they will navigate your home very well in the dark.
How a cat sees at night: The final word
Cats don’t have the absolute vision they are often granted in nighttime conditions, but they are nonetheless much more adapted to seeing in the dark than we are.