Animal World


Why do cats’ eyes shine in the dark?

The function of a cat’s whiskers is not fully understood. They are thought to have something to do with the sense of touch. Removing them can disturb a cat for some time. Some people believe that the whiskers act as antennae in the dark, enabling the cat to identify things it cannot see. The whiskers may help the cat to pinpoint the direction from which an odor is coming. In addition, the cat is thought to point some of its whiskers downwards to guide it when jumping or running over uneven terrain at night.

A cat’s eyes contain a special light-conserving mechanism called the tapetum lucidum, which reflects any light not absorbed as it passes through the retina of each eye. The retina gets a second chance (so to speak) to receive the light, aiding the cat’s vision even more. In dim light, when the pupils of the cat’s eyes are opened the widest, this glowing or shining effect occurs when light hits them at certain angles. The tapetum lucidum, located behind the retina, is a membrane composed of 15 layers of special, glittering cells that all together act as a mirror. The color of the glow is usually greenish or golden, but the eyes of the Siamese cat reflect a luminous ruby red.


This is a web preview of the "The Handy Science Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App