Nature has created us in such a way that we can perform all our tasks with the given organs. Evolution has taken care of the fact that our changing requirements are met by our capabilities. Cats are nocturnal animals that prey when darkness falls. They need to see both in daylight and in dark nights. A cat’s eye glows in the dark or at night so that it can see its ways around and can catch a rat or hunt for food. Whether you possess a pet cat or not, you have probably noticed how the eyes of cats gleam and shine in the dark and felt curious.
The reason why cat’s eyes gleam and glow in the dark is their capability of reflecting light. The eyes of cats are larger than humans. They have a very special sort of cells at the back of their eyes known as tapetum lucidum. This special layer of cells combined with the large size of their eyes help them spot preys in darkness and they can also easily find their way in the dark. The tapetum lucidum is composed of a substance named guanine. This substance makes the reflective capacity of tapetum lucidum stronger.
The job of the tapetum lucidum is just the same as a reflective mirror. The light that falls on the eyes of the cats is reflected by this mirror like cells onto the surface of the retina. The retina then helps the cats see better even in apparent darkness. Humans do not have the layer of cells called tapetum lucidum and that’s why they cannot see as well as the cats in the dark. Cat’s can see 6 times better in dim light or darkness than humans. Being nocturnal by nature it is the only way they can survive and hunt.