Cats are nocturnal animals. They have a very active nightlife (just like some humans!).
So here are some facts about cat vision at night.
1- Cats can see in the dark
Cats (just like us humans) can’t see a thing in total darkness. The retina needs photons (the particles in light) to impact its light receptors to send a vision nerve impulse to the brain. In absolute darkness, there are no photons. However, cats can orient themselves in the dark quite well, thanks to a fantastic sense of smell just as dogs
2- Cats have night vision
Cats can see in the dark because their eyeballs are well adapted for nightlife. The retina has two light receptor types, cones for colors and rods for seeing in dim light. Cats happen to have a large number of rods. This relative abundance of rods means cats have an excellent contrast vision at night that we humans know more like black and white or colorless vision.
Cats (and dogs) have night vision because relatively numerous rods are very good at catching the scarce photons present during nighttime. Then, with the help of brain vision regions (mainly the visual cortex), they can put together high-contrast images of the world.
However, not all is about the contrast. Cats can also see the depths and details of objects at night.
3- Cat’s night vision is similar to a human’s vision
In a cat night vision vs. human contest, cats win by large! This is because humans have a predominance of cones in the retina, which enables color vision, more suitable for day vision. On the contrary, having a lower concentration of rods in the retina, our nocturnal vision is not as good as cats’. Similarly, like dogs, cat color vision, more suitable for day circumstances, is limited to hues of olive greens, browns, and yellows.
4- Cats’ eyes glow in the dark
Cats’ eyes (and other animals) glow in the dark when a light source points to their eyes because of the presence of a particular layer in the eyeball called (from Latin) tapetum lucidum. This layer reflects light (photons) inside the eye, concentrating them into some areas of the retina to optimize night vision. Humans (and primates in general) do not have this structure, and this is another difference between the cat and the humans’ vision.
Many wild animals have tapetum lucidum and their eyes glow in the dark (like foxes and raccoons). Other animals, as well as humans and primates in general, do not have tapetum lucidum Examples are pigs and squirrels.
In summary, cats are predatory by nature and nocturnal animals. They cannot see in total darkness but get their way easily using their extraordinary smell sense.