Domestic cats

Why do cats have eyes in the dark?

Why do cats have eyes in the dark?

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Content
  1. How does the cat's eye?
  2. Features of view
  3. Reasons for the glow
  4. Why does color differ?
  5. How to explain to children?

Cats are amazing and unique animals. Not for nothing was a special relationship to them in different cultures. Some of them were considered sacred animals, others were attributed to the servants of the dark forces and were afraid. One of the reasons is the uniqueness of their view. Everyone knows that in the dark their eyes flash with bright lights. Let's see if there is any mystery in this.

How does the cat's eye?

If we compare human and cat eyes, we can find a number of differences. It is they who determine the peculiarities of their vision. We do not want to confuse you with abstruse biological terms, so we will try to talk about how the cat's eye works, simply and clearly.

The figure shows the schematic structure of the cat's eye. Each element serves a specific purpose. Their functions and characteristics define the cat's eye.

  1. Sclera. The outer shell that supports the correct shape of the eye.
  2. Cornea (stratum corneum). Performs protective functions. It has a convex shape and protects the delicate iris and pupil from external damage.
  3. Vascular layer. Without it, the functioning and nutrition of the eyes would be impossible. Yes, they also need nutrients and oxygen.
  4. Lens. Many represent this body in the form of a cut diamond. But in fact - it is a liquid substance. However, its functions are very similar to a real diamond. It also refracts and transforms the incoming flow of light.
  5. Retina. Due to the presence of photoreceptors, this organ is responsible for perceiving the entire luminous flux that has passed through the cornea and lens. The first and very important feature of the cat's view lies precisely in this. The fact is that with us and with our smaller brothers, photoreceptors are represented by cones and chopsticks. Their ratio determines the sharpness and susceptibility of the eyes. So, in cats, the overwhelming majority are made up of rods (there are 25 times more than cones).
  6. Tapetum. This is a special reflective layer, which nature has endowed the feline. Thanks to him, they have such sharp eyesight 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 have passed by the retina will be captured and reflected by this layer. This means that the brain will receive more information from the optic nerves.
  7. Optic nerve. Information obtained 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 eyes of a cat. The fact is that these main parts are directly related to our topic. Already on the basis of this information it becomes clear that the vision of cats is unique, although in many respects similar to ours.

Features of view

So, we have considered the components of the cat's eye. Now it remains to draw conclusions, and learn about the features.

  • Even with the naked eye it is clear that the organs of vision of our pets are planted quite deeply. Therefore, it is more difficult for them to consider peripheral objects. The 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 turns into a narrow slit.The fact is that this amount of light rays (which pass through it) will be enough to give full information to the brain about the environment.
  • Direct exposure to sunlight is detrimental to the eyes. It's all about their sensitivity. On average, it exceeds the human 7 times.
  • Each eye has its own visual field. That is, the area around which he reads the information (receives a stream of light). The fields of the left and right eyes intersect. This explains the fact that cats see a three-dimensional image.
  • Our pets have color vision, although it is different from ours. They perfectly distinguish the shades of the upper spectrum (blue, blue, green). But all the shades of red they see in gray. The same applies to colors such as orange and yellow.
  • If it is easier for us to see any object in statics, then inborn hunters will focus on moving objects. This feature becomes critical in the wild. That is why the cat will notice even the slightest stirring or movement in the apartment.
  • The cat has no blind spots. Drivers are familiar with this concept. But some herbivores have places that they simply cannot see. They are directly in front of the animal's face. For hunters, this is unacceptable.

Reasons for the glow

At night, leaving the room and accidentally stumbled upon his pet, you can see how his eyes are lit with bright lights. But despite this common expression, their eyes do not shine. But how so?

The thing is that a particular layer, 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 its unique vision cannot see in total darkness. In order for the brain to receive information, at least a weak light source is necessary. Many will argue that they have seen 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 absolutely dark, but for the cat family there is enough of this amount.

Why does color differ?

Many may have noticed that in different breeds of cats the retina has a different color. It really is. But this is not at all the main cause of different luminescence.

The whole thing is again in the mirror layer on the back of the eye. With the same structure, this body may have different chemical composition and pigmentation. Due to this, the shades are obtained from yellow to purple. Most often, we see green and yellow reflections.

Different colors are also explained by the structure of this layer. In some, it covers the entire back wall, in others - there are pigmented areas. As well as the colors are refracted because of the interlayer, it is she who gives a 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 eyes? It is also nothing more than a reflection of light rays. A red light is due to the presence of vascular compounds, which stain the flow in a given shade.

How to explain to children?

Of course, it is much easier for adults to explain one or another scientific fact. But when a small child comes to you and asks why the eyes of the cat shine, it can be difficult. You will not tell the little restless about the complex structure and the refraction of light. For him it will be incomprehensible.

However, one does not want to mislead the kid and say that this is a magical power with which all cats are endowed. After all, most of our beliefs are formed in childhood. What will be his surprise when the lessons of physics and biology will tell him about these features.

Here you can choose for yourself two ways.The first is to tell the child a legend that is not without meaning and scientific justification. And it literally reads as follows. In ancient times, cats did not have such an acute vision. But since they hunted only at night, they just needed to see in the dark. Then the good-natured goddess took pity and presented them with the ability to collect even small rays of light. They were going in the eyes of the cat and lit her way.

Despite the fabulous subtext, this legend has a right to exist. After all, by and large everything happens that way.

You can try to explain to your child the cat's eyes glow and in a more prosaic way.. Take a small flashlight, go to the mirror and direct it to the mirror. Let the baby see how the light is reflected and becomes visible. Then we can say that your favorite kitty has small mirrors hidden in their eyes, which also reflect the light. Only she does not need to shine a flashlight in her eyes for this, even a weak moonlight will suffice.

It is worth noting that in Russia it was believed that through their eyes dark forces were spying on people. Therefore, it was not recommended to look the cat in the eye.

In Europe, in the period of the Great Inquisition, these animals fell under even more disfavor. They were considered servants of Satan and ruthlessly exterminated. The end of this story was sad, since extermination led to an increased number of rats and mice and the epidemic of Bubonic plague.

Visually about the causes of eye lightening in cats, see below.

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Information provided for reference purposes. Do not self-medicate. For health, always consult a specialist.

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