We all know that cats have special eyes. Its pupil size can be adjusted. When the light is bright, its pupils will be squeezed into a line. When the light is very dark, its pupil will enlarge into a big circle, and sometimes it can even expand to occupy more than 80% of the eye area, which reflects its eye's adjustment of luminosity. It is said that the night vision ability of cat eyes is six times stronger than that of people.
The bright carpet mentioned above is an artifact of Nocturnal Animals, which plays a very important role in the night hunting of carnivores. Is it normal for a cat's eyes to glow at night and emit red light? Its main function is to return some light from the retina to the retina, so that the photosensitive cells on the retina are stimulated by photons for the second time, which improves the utilization rate of light. This is why cats can see their prey clearly in dim light. This part of the light reflected from the bright carpet is visible to the human eye and is called "cat's eye glow". Usually green light is dominant, and there may be blue light or yellow light.
Many similar animals don't have bright carpets, and neither do humans and other primates. At this time, the light entering the eye is reflected on the choroidal blood vessels, revealing the color of the blood vessels. Most blue-eyed and white cats don't have blankets, so red blood vessels are often reflected when taking pictures. In this way, it is normal for a cat's eyes to glow at night and emit red light when taking pictures. Don't worry too much about shovels! Animals that can see in weak light have a special reflective layer in their eyes, which is called a reflective film. Reflective film is more reflective than retina, so it can capture more light and see more clearly in the dark. When the cat's pupils are dilated in the dark, what we see is actually the light captured on the reflective film.