People have been living next to cats for over a thousand years. These amazing and mysterious animals fascinate people with their refined grace, beauty and gentle manners. At various times, humanity worshiped cats, equating them to deities, such as in Ancient Egypt. Tailless cats were revered in Japan, so the Japanese bobtail breed has appeared. Figurines of such cats can still be found in many houses of the Japanese islands. And in the Middle Ages in Europe, people were afraid of cats, burning black cats on fires together with their hostesses, considering these unfortunate women as witches.
Many superstitions and omens were associated with cats, until now some people think that a meeting on the street with a black cat does not bode well. But nevertheless cats have managed to subdue human hearts; these furry creatures live in almost every family. No matter how well we know our furry friends, they are surrounded by many secrets and mysteries. How do cats foresee earthquakes, how do cats find their way home for a few hundred kilometers, and, of course, why do cats’ eyes glow in the dark? Glowing cat’s eyes in the dark became the reason for a lot of stories, fairy tales, and this image is quite often used in the cinema.
Nevertheless, the effect of the glowing eyes of a cat has a completely scientific explanation. As with most carnivorous animals that are nocturnal, cat’s eyes are arranged in such a way that any light, even a weak reflection of the moon or the stars glow, can be reflected in them. The eyes themselves do not produce any light, of course.
You can conduct a small experiment by yourself. If you close the cat in a dark room without windows, then make sure that in absolute darkness its eyes do not glow. The cat’s eyes are capable of reflecting light of an external source: if there is a light glow of the night sky, a bright flash of the car’s headlights, then the cat’s eyes look like small spotlights. All the matter is that an internal part of a cat’s eye is covered with a layer of brilliant transparent cells called tapetum. The silver tapetum is very similar to a mirror, and it is able to reflect light. Even the weakest ray of light, getting through the crystalline lens and the cornea into the eye, is not completely absorbed, but is reflected back by a thin beam of light. This feature helps cats to see well at night.
The color of the eye glow of different animals depends on the pigment that is in the tapetum. Cats often have yellow and green color. Much rarer there can be other tints. For example, Siamese cats have a crimson pigment of a tapetum.
The cat’s eyes are more sensitive than the human eye seven times. But people also have a weak glow effect, if to use a bright flash. So sometimes on colored photos people’s eyes can have a red color.