Do you know why some animals can see in the dark?

Animals have many abilities that allow them to survive in various conditions. One such phenomenon is the ability to see in the dark, which is possessed by creatures accustomed to nightlife.

We humans have pretty good eyes by animal standards. And we also have the ability for night vision, but it is very weak. It is enough to find the switch in the dark, but that's all. But some representatives of the animal world can easily navigate and hunt even in very low light levels.

See animals in the dark may due to the presence in the eyes of a large number of photoreceptor cells called rods. They contain the pigment rhodopsin, which animals adapt to low light levels and capture even single photons of light. And then there are photoreceptors called "cones" - they provide color vision.

For example, in a cat per square millimeter of the retina account for 350 thousand sticks, and in humans - only 80-150 thousand. At

cats 25 rods for each cone, and a person has only four. In addition, the lenses of many nocturnal predators are larger than those of humans, and they are able to collect more light.

But such an eye device also has a minus: nocturnal animals do not perceive colors well during the day.

The same cats, for example, do not see the difference between red, brown and green, although they can distinguish blue. In general, they should not be graphic designers.

In addition, the organs of vision of many nocturnal animals have a special layer of reflective cells located behind the retina - tapetum. It contains special pigments that return light entering the eye, passing it back through the retina. The tapetum allows photoreceptor cells to catch photons passing by them for the first time, further enhancing dark adaptation.

It is because of this layer that the eyes of cats, dogs, fox, owls and many other animals glow at night. But if you lock yourself up with your pet in a windowless room, you will notice that this will not happen in absolute darkness. It's just that there's no light there to reflect the tapetum.

Finally, some nocturnal animals resort to a kind of "post-processing" of the image that comes from the photoreceptors in their brain. Eg, frogs and geckos can recognize colors even in very dim starlight. The neurons of their brain are able to artificially amplify the signals coming from the optic nerves and filter out light noise. Therefore, these creatures can see colors when others see only shades of gray.

All this allows animals to hunt, navigate the terrain and avoid danger even in very low light. So the ability to see in the dark is a very good thing. Another thing is that nocturnal animals in the light will be much inferior to daytime predators.