Why do cats have eyes in the dark?

The content of the article

1 Glittering eyes, what is it: magic or a physiological feature?
2 Will the cat's eyes glow in complete darkness?
3 When does the red eye appear?
4 Video: why cats have eyes glow in the dark

Cats are animals that are distinguished by extraordinary beauty and stand out among many species on our planet. Representatives of the cat family have some features in their appearance, which make these animals so graceful and beautiful. Cats are loved primarily for soft and silky fur, refined movements, as well as independent behavior. There is also another interesting property of these animals - eyes that glitter in the dark.

Since ancient times, this particular feature forced cats to be considered magical animals, favorite witches' pets, which conceal a large number of secrets. A lot of questions arise as to why cats have eyes in the dark?

Glittering eyes, what is it: magic or a physiological feature?

If you understand in more detail in this phenomenon, it can be understood that the glaring eyes in cats - this is a common misconception. The fact is that all animals that have the ability to exist at night, have on the inner side of the eye a special shell called tapetum. This layer is composed of guanine, as well as various pigments, which give the eyes of animals a certain color. Among the representatives of the cat family, this is most often green or yellow; in dogs, dark brown shades or varieties of blue. But in fish there are milky eyes.

It is this transparent layer of tapetum and gives some glow to the cat's eye. It is of considerable importance for these animals, helping them to see better under various conditions. The main problem of the organs of vision is that the photoreceptors perceive far from all the colors that appear before them. Comes to the aid of a transparent layer, which reflects the remaining light on the retina of the eye. As a result, more information flows to the brain. Accordingly, nature is designed so that the glow in the eyes of cats helps them see better in the dark, and, accordingly, makes it possible to hunt at night. However, do not confuse the reflection of light from its source.Cat's eyes are not lights that can shine in the dark, the principle of tapetum functioning is somewhat different.

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Will the cat's eyes glow in complete darkness?

There is a rather popular puzzle that asks how to find a cat in absolute darkness. The answer in this case will be - the inclusion of light. Many answer this question that the cat can be found by luminous eyes, however, it is not. As it was already possible to understand, the sparkling layer in the eyes of the cat is not capable of producing luminescence on its own; it needs at least some minimal source of light to reflect this light. For example, if you direct a lantern or other powerful source of light towards an animal, you will see how the cat's eyes literally flash.

It is surprising that a tapetum can reflect even small, barely noticeable glares, for example, the light from electronic gadgets, glare from crystal dishes or chandeliers, reflections of a street lamp. At night, the main source of light is the moon. For this reason, even in a rather dark room you can see the glitter of cat eyes.

Sometimes the cat's eyes glow so much that such a phenomenon even scares a little. It should be noted that the intensity of the brightness depends not only on the light source, but also on the angle at which the light falls on the transparent layer of the animal's eye. In addition, it affects the strength of the glow and the angle at which a person looks at the eyes of a cat. The brightest glitter can be seen when the light hits the cat's eye retina at a 45-degree angle, while the person looks directly into the face of the animal.

The representatives of the cat family themselves do not notice the same effect and the difference between the intensity of the reflection of light from the transparent layer of the retina. You can see that this is true when changing the direction of light to the cat's eye, as well as the power of the source. With such changes, it can be noted that the animal does not have a characteristic squinting in this situation.

But you can notice the screwing up of a cat when the light falls directly on the retina of the animal's eye. The fact is that in this case there is a kind of overload and severe irritation of the light receptors located on the retina.In the daytime, in a bright room, it is almost impossible to note the effect of retinal glow, since under such conditions the light completely penetrates the eye, as a result of which light does not need to be reflected from the transparent layer. The cat at the same time very well sees even without additional help.

When does the red eye appear?

An interesting fact is that in humans, the eyes can also glow, like a cat. Of course, in humans, this property does not manifest itself as intensely as in cats or other animals, because a person is not able to see in the dark. Actually, we don’t have such a need, because people do not hunt in the dark, and in general food is mined in other ways. However, a similar transparent layer is still present in the structure of the human eye. It is this feature in conditions of poor visibility with a bright flash that gives a red-eye effect on photographs. To get rid of this phenomenon, you only need to prepare good indoor lighting before shooting.

Thus, we can conclude that the glow of the eyes in cats is an effect that has nothing to do with magic.This fact should be regarded only as an element of adaptation to the conditions of life. In addition, it can be understood that in the red-eye effect people do not have anything supernatural or unusual. These phenomena are quite easily explained in terms of physiology.

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