There are a thousand Hamlets in the eyes of a thousand people, and the world in the eyes of different species is also different. We humans naturally think that this world is colorful and colorful, but if you ask the cat, it will definitely disagree....
There are a thousand Hamlets in the eyes of a thousand people, and the world in the eyes of different species is also different. We humans naturally think that this world is colorful and colorful, but if you ask the cat, it will definitely disagree.
After all, have you seen colorful cats?
1. Cats with different fur colors
The above picture basically includes all possible colors of cats: white, black/gray, yellow/brown. Why are there no red, green, and purple cats? In fact, this has something to do with the color that cats can distinguish. Research has found that cats' color discrimination ability is similar to that of humans with red and green blindness.
How do human eyes distinguish colors?
Humans can see and see things clearly mainly because there are two photoreceptor cells on our retina: rod cells and cones.
Root cells play a role in dark light and do not have the ability to distinguish colors. Therefore, in a dim environment, we can only roughly see objects, but we cannot distinguish colors.
In bright light environments, cones are the ones that play a role. Normally, there are three cones on the human retina that can sense red, green and blue, and the colors in nature can be composed of three primary colors: red, green and blue. Therefore, different colors can be distinguished according to the different spectrums sensed by the three cones.
2. What is color blindness?
When some or all of the three cones have problems, color vision disorders occur. Color vision disorders can be divided into total color blindness and incomplete color blindness:
People with complete color blindness have lost all their color function and can only distinguish between black, white and gray;
People with incomplete color blindness can recognize some colors, but they cannot recognize some colors, and the most common one is red and green blindness.
From the spectrum, the wavelengths of red and green are very close, but humans are particularly sensitive to this wavelength. From the figure, we see that cones appear two photosensitive peaks near 550 nm, so we can accurately distinguish the colors of red, yellow and green in this area.
