Many people think that cats are colorblind but this is not the case. It is true that cats do not see in the same way that most humans do, however thinking that they don’t see any colors at all is simply not true. Rather, cats are able to distinguish between blues and greens but lack the ability to distinguish shades of red. This means that they only see in these two different colors, blue and green. So for instance, when a cat sees anything that we would describe as red, orange, yellow or green, to a cat they are all the same color. Furthermore all shades of blue and violet are seen as one color to a cat.
Like humans cats have two primary structures located in the retina of their eye for perceiving light. These two structures are known as rods and cones. Rods help us humans see light and dark areas, and cones, the color sensitive cells in the eye are what detect particular wavelengths of light thanks to the pigments they have. However where humans have three varieties of cones that help us distinguish over one hundred different hues of color, cats only have two kinds of cones that are most sensitive to green and light blue. It has been suggested that the inability in cats to distinguish between colors may have evolved due to the fact that they are night hunters and colors are not discernable in reduced light, nor do they really need to see in color in order to hunt well. A mouse or a bird is still dinner to a cat, no matter what color it is.
The way a cat’s eye is designed is very unique. They have good vision in both high and low levels of light. They may not be able to distinguish colors in the same way many humans do, but that isn’t to say that they can’t see well. In fact, A cat’s iris can open up very wide to let in a lot of light so that even when they are surrounded in darkness and there isn’t much light around, they can let in as much of the light as possible. Cats also have light sensitive structures in the makeup of their eyes and a mirror like layer (tapetum lucidum) located in the back of the eye which helps reflect any light available back towards the front of the cat’s eye when there otherwise wouldn’t be much light in the room. This reflective area is what makes cat’s eyes “glow” at night when headlights shine on them.