On a bright day, apathy comes over the cats. They are able to lie for hours without moving under the warm rays of the sun. In winter, they try to grab a place near the radiator or in a warm chair. But with the arrival of darkness, the behavior of animals changes. They are active, which even causes discontent among vacationing owners. At night, the genes of distant ancestors of wild nature, who began to hunt at the end of the day, are activated in cats. It is precisely for such a case that nature provides a special structure for cat’s eyes, which have the ability to capture even weak light - the radiance of the moon, star rays and even the glare of a flame. Let's try to figure out why a cat's eyes glow in the dark, at night.
Why is it possible that a cat’s eyes glow in the dark?
Naturally, today scientists have long found an explanation for such amazing abilities, and cats have turned from mysterious creatures into harmless pets. But their eyes continue to glow in the dark with a bright and sometimes frightening light.
Cats are amazing and unique animals. It was not without reason that they had a special attitude in different cultures. Some considered them sacred animals, others considered them servants dark forces and were afraid. One reason is the uniqueness of their vision. Everyone knows that in the dark their eyes flash with bright lights. Let's see if there is at least some mysticism in this.
How does a cat's eye work?
If you compare human and cat eyes, you can find a number of differences. It is they who determine the peculiarities of their vision. We don’t want to confuse you with abstruse biological terms, so we’ll try to tell you how a cat’s eye works, simply and clearly.
The figure shows the schematic structure of a cat's eye. Each element serves specific purpose. Their functions and character traits determine the characteristics of a cat's vision.
- Sclera. Outer shell that supports correct form eyes.
- Cornea (stratum corneum). Performs protective functions. It has a convex shape and protects the delicate iris and pupil from external damage.
- Vascular layer. Without it, the functioning and nutrition of the eyes would be impossible. Yes, they need it too nutrients and oxygen.
- Lens. Many people imagine this organ in the form of a cut diamond. But in reality it is a liquid substance. However, its functions are very similar to a real diamond. It also refracts and transforms the incoming light.
- Retina. Thanks to the presence of photoreceptors this body is responsible for the perception of the entire light flux that passed through the cornea and lens. The first and very important feature The cat's vision lies precisely in this. The fact is that in both us and our smaller brothers, photoreceptors are represented by cones and rods. Their ratio determines the sharpness and sensitivity of the eyes. So, in cats, the overwhelming majority are rods (there are 25 times more of them than cones).
- Tapetum. This is a special reflective layer that nature has endowed cats with. Thanks to him, they have such sharp vision and see well in the dark. Everything is simple here. In humans, only the retina captures streams of light, but not all of them fall on it. In a cat, even those rays that pass by the retina will be caught and reflected by this layer. This means that the brain will receive more information from the optic nerves.
- Optic nerve. Information received by the retina and reflected from the tapetum is converted into electrical impulses that directly enter the brain and are processed there.
We did not list absolutely all the organs that make up the cat’s eye. The fact is that these main parts are directly related to our topic. Already based on this information, it becomes clear that the vision of cats is unique, although in many ways similar to ours.
Features of vision
So, we looked at the components of a cat's eye. Now all that remains is to draw conclusions and learn about the features.
- Even the naked eye can see that our pets’ visual organs are set quite deep. Therefore, it is more difficult for them to see objects located on the periphery. This same feature explains the limited mobility of the eye itself.
- The pupil is located vertically. Its size depends entirely on the lighting. The stronger it is, the narrower it is. In daylight, it completely turns into a narrow crack. The fact is that this number of light rays (which pass through it) will be enough to give full information brain about the environment.
- Direct hit sun rays has a detrimental effect on the eyes. It's all about them hypersensitivity. On average, it is 7 times greater than that of humans.
- Each eye has its own visual field. That is, the area around from which it reads information (receives a stream of light). The fields of the left and right eyes intersect. This explains the fact that cats see three-dimensional images.
- Our pets color vision, although it is different from ours. They perfectly distinguish shades of the upper spectrum (blue, indigo, green). But they see all shades of red in gray color. The same applies to colors such as orange and yellow.
- If it is easier for us to see any object in a static state, then for born hunters the emphasis is shifted to moving objects. This feature becomes critical in wildlife. This is why the cat will notice even the slightest movement or movement in the apartment.
- A cat has no blind spots. Drivers are very familiar with this concept. But some herbivores also have places that they simply cannot see. They are located directly in front of the animal's muzzle. For hunters, this is unacceptable.
Reasons for the glow
At night, leaving the room and accidentally bumping into your pet, you can see its eyes burning with bright lights. But contrary to such a common expression, their eyes do not glow. But how can this be?
The thing is that the special layer, the tapetum, which we talked about earlier, is a mirror surface. Even the slightest stream of light falling on it is reflected. And we see precisely this reflected light.
Contrary to popular belief, Even a cat with her unique vision cannot see in pitch darkness. In order for the brain to receive information, at least a weak light source is needed. Many will argue that they saw how the eyes of these animals flash in the dark. The fact is that those weak sources of light that exist in this darkness are not perceived by the human eye. It seems to us that the room is completely dark, but for the cat family this amount is enough.
Why does the color vary?
Many may have noticed that different breeds The retina of cats has different colors. This is indeed true. But this is not at all the main reason for the different glow.
It's all about the mirror layer on the back wall of the eye. With the same structure, this organ can have different chemical composition and pigmentation. Due to this, shades from yellow to purple are obtained. Most often we see green and yellow reflections.
The different colors are also explained by the structure of this layer. For some it covers everything back wall, others have pigmented areas. And also the colors are refracted due to the layer, it is this layer that gives the green glow.
If you think that only our pets have such a unique feature, then you are mistaken. Look at your photos. Do they have an effect called “red eye”. This is also nothing more than a reflection of light rays. And the red light is explained by the presence of vascular connections, which color the flow in this shade.
How to explain to children?
Of course, it is much easier for adults to explain this or that scientific fact. But when it comes to you Small child and wonders why the cat’s eyes are glowing, then difficulties may arise. You won’t tell the little fidget about the complex structure and refraction of light. It will be incomprehensible to him.
However, I also don’t want to mislead the baby and say that this is a magical power that all cats are endowed with. After all, most of our beliefs are formed in childhood. Imagine his surprise when they tell him about these features in physics and biology lessons.
Here you can choose two paths for yourself. The first is to tell the child a legend that is not without meaning and scientific basis. And it literally says the following. In ancient times, cats did not have such acute vision. But since they only hunted at night, they simply needed to see in the dark. Then the good-natured goddess took pity and gave them the ability to collect even small rays of light. They gathered in the cat's eyes and illuminated her path.
Despite the fabulous overtones, this legend has a right to exist. After all, by and large, this is exactly what happens.
You can try to explain to your baby the glow of a cat’s eyes in a more prosaic way.. Take a small flashlight, go to the mirror and point it at the mirror. Let your baby see how the light reflects and becomes visible. Further, we can say that your beloved cat has small mirrors hidden in her eyes, which also reflect light. But she doesn’t have to shine a flashlight into her eyes for this; even a faint moonlight will be enough.
In daylight, cats become apathetic. They can bask in the summer sun for hours without moving. In winter, sloths can spend the whole day in a cozy soft chair, closer to the radiator. But with the onset of dusk, their behavior changes. Murlyka forgets that only recently he was too lazy to even open his eyes, and begins to show activity, which does not always please sleeping family members. When night falls in cats, the genes of their wild ancestors wake up, going out to hunt at sunset. It was for effective night hunting that Mother Nature provided a special structure for the eyes of the entire cat tribe, capable of capturing the faintest light: moonlight, star rays or the reflection of a distant flame.
Source of fiction and superstition
When you see brightly glowing cat eyes in the darkness, all sorts of superstitions and fictions with which this amazing land has acquired over many centuries involuntarily come to mind. cat feature. How often people, not understanding the true nature of phenomena, come up with the most incredible explanations.
So the ability of purrs to scare passers-by in the pitch-black night with their lantern eyes did not escape this fate. For many centuries, people considered this amazing natural phenomenon to be a demonstration of the connection with evil spirits. Due to their nocturnal lifestyle and glowing eyes, cats were credited with many witchcraft abilities. In the Middle Ages, it was believed that their strength depended on the color of their coat and eyes. Animals were considered faithful companions and assistants to witches and sorcerers.
Of course, nowadays scientists have long found an explanation for these supernatural abilities, and cats have turned from creatures frightening with their mystical talents into harmless pets. But the eyes of animals in the dark continue to glow just as brightly and sometimes frighteningly.
Why do cat eyes glow in the dark?
To witness such a phenomenon, you need the cat itself, the onset of night and a weak source of light. In absolute, pitch darkness, you will not be able to see not only the cat itself, but also its burning eyes. And all because this is how the eyes of these nocturnal predators are designed.
The muscles of the iris are able to control the flow of light onto the retina and, if the light is too intense, they signal the pupil to narrow to a thin slit. That is why during the daytime we do not notice the reflected glow that a cat’s eyes emit. But in the dark, the pupil opens completely and the streams of light reflected by the “mirror” of the fundus are noticeable from afar.
On the inner surface of the eye there is a special layer of photoreceptors (tapetum), capable of capturing and reflecting even an insignificant amount of rays that pass through the cornea and lens and reach the fundus of the eye. This reflected light comes back out, helping the cat see in the dark. In order for the purr to navigate perfectly and even hunt, just the lighting provided by the stars and the moon is enough. But if the animal finds itself in a completely dark room, then find a way out of it amazing vision It won't help her anymore. You will have to make do only with hearing and smell, which, however, are also excellently developed in this extraordinary animal.
It is surprising that the coating on the fundus of different animals differs not only in size, but also in the concentration of the dye. Usually it has a yellow-green tint, sometimes other colors (for example, crimson - in cats Siamese breed). In albino individuals, the reflective layer is completely devoid of pigment, and therefore the glow of the eyes of such an animal in the dark will have an eerie red tint. This phenomenon can seriously frighten an unprepared person, especially considering that cats appear absolutely silently and therefore always unexpectedly.
The cat's activity at night is inherited from its ancestors (wild cats). To navigate well in the dark, cats have a special structure of eyes that capture light from various sources, car headlights, the reflection of distant stars, and other light sources.
Why do a cat's eyes sparkle in the dark?
On the inner surface of a cat's eye there is a highly sensitive photoreceptor that helps her see at any time of the day. During the daytime, the pupils are constricted, and when night falls, they open wide to capture any light well.
The common misconception that the eyes of all nocturnal predators produce light is a mistake. In reality, the eyes simply capture even the weakest light. Due to this structure, a cat's eye can enhance a slight glow. Certain nerve endings in the retina of the eye are responsible for the function of night vision. As soon as light of any intensity appears, these nerve endings begin to show blurry images. To control the flow of light, the iris muscles tell the pupil to contract or dilate. By the way, you also need to take care of your cat’s eyes, how? Read the link.
Light passing through the pupil enters the inner chamber of the eye and is reflected from a layer of cells, the surface of which is shiny. This mirror-like surface instantly reflects light back onto the retina. That’s why cats see so well in the dark, but on one condition: there must be at least a small light source. It is only due to an external light source that a cat’s eyes sparkle and shine so brightly. If you place a cat in a completely dark room, without a single source of light, then in such darkness the eyes will not glare and the cat will not be able to see anything. She will need to get out of this darkness relying only on her excellent sense of smell and hearing.
Various superstitions and guesses associated with the glow of a cat's eyes
Due to this structure of the eye, darkness provides enormous opportunities for predators, allowing them to go unnoticed while others are blind.
When in the dark you see the big, diamond-glittering eyes of a cat, people have come up with various legends and superstitions. This visual phenomenon was considered to be a manifestation otherworldly force. Superstitious people, seeing the burning eyes of a black cat in the dark, were horrified.
A black cat or female cat used to be considered faithful companions of various witches and sorcerers. The nocturnal lifestyle and burning eyes endowed the cat with supernatural power, which was either valued or subject to persecution. For example, in France, in the Middle Ages, it was believed that cats were witchcraft creatures, whose strength depended on the color of their fur and eyes. Many misconceptions and superstitions were attributed to cats simply because they have a special sense of smell and excellent hunting instincts, which simply actively manifest themselves at night.
Nowadays, no one believes in all these medieval misconceptions, and cats have become our full-fledged family members who are loyal and obey their owner.
Have you ever been scared of a cat's burning eyes in the dark?
I bring to your attention 2 funny videos about the glow of a cat’s eyes in the dark.
Your beloved pet can look adorable during the day, squinting in the gentle sun. But the coming night often gives cats a simply creepy appearance. Why does your favorite animal become like a fiend from hell as soon as the darkness thickens around it? Where does this chilling golden or terrifying green glow come from at night? What happens to our cats in dark rooms?
Leading veterinary ophthalmologists from the USA - Dr. Cynthia Powell from the University of Colorado and Dr. Bill Miller from Ophthalmology Clinic animals in Memphis, Tenn.
How does a cat's eye work?
Our mischievous furry pets, like us, have binocular vision. The cat sees well what is in front of it; the viewing angle is relatively small (for example, in some ruminants it can reach 360 degrees).
Bottom eyeball cats are coated with a special substance that can be compared to the amalgam of a mirror or silver. It is thanks to this substance that a ray of light cutting through the twilight is reflected and returns to its starting point.
Cats are excellent hunters. Good vision they just need it. They can very quickly estimate the distance to an object in order to intuitively choose a jump trajectory. True, this does not prevent some pets from being quite clumsy at times.
But no matter how sharp our pets may seem to us, their vision cannot be called phenomenal. For example, a person distinguishes many more shades. Cats see the world in shades of gray and brown, and some colors don’t even exist for cats. For example, they don't see red. But usually they don’t need this, because the main prey provided for by nature for a cat are gray mice and brown birds. An excellent sense of smell helps animals navigate.
Special feature for hunters
The cat's eye is proportional to the human eye, but has a layer of reflective cells known as the tapetum. Big sizes The eyes and tapetum help the cat to see movement and objects better in dim lighting.
Tapetum located between optic nerve and the retina, works like a mirror. It reflects light, and this gives the cones and rods located in a cat's eyes another opportunity to absorb the limited amount of light available at night.
This anatomical feature proves to be an asset for animals that hunt at dawn and dusk. It was transmitted to a cat domesticated several thousand years ago from its wild ancestors.
Dr. Miller explains that glowing eyes Many animals are designed for low light. Dogs, cats, large cattle, deer, horses, ferrets. However, humans and primates do not have a tapetum because they are more active during the day. Our retina is designed for brighter lighting.
The eyes of cats of different breeds glow differently
Most cats' eyes tend to glow bright green. But Siamese cats often emit a bright yellow hue. The specific color of the glow varies depending on the animal and the amount of zinc or riboflavin present in the pigment cells in the tapetum nucleus.
Dr. Powell explains that zinc is a metal and riboflavin is an amino acid. Both elements act as reflectors.
Depending on how saturated these cells are with zinc or riboflavin, the color of the glow may vary.
Dogs and ferrets have zinc in their cells, but riboflavin predominates in cats.
Glow intensity
This special luminescence also depends on the age of the animal, as well as the color of its iris and even the color of its coat. Age can change reflectivity as lenses become denser, says Dr. Powell. This reduces the ability of the animal's eyes to reflect light.
The eyes of a cat with a white coat, which are blue in normal light, may turn red in dark conditions. They look red because blood vessels in the eyes, which also reflect light.
As for tips for reducing that glare when using camera flash, Dr. Powell has a suggestion. If you want to photograph your pet in limited light conditions, without being able to use an external flash, take two frames in a row without leaving a long pause between them. Use the camera's built-in flash. The first flash will cause the pupils to constrict, reducing light reflectivity, but the photo is unlikely to be successful. Immediately do the second one, before the animal’s pupils have time to dilate. This shot is most likely to turn out well.
