I don’t know about you, but looking at a cat’s eyes glow in the dark always looked kind of spooky to me. But have you ever wondered why do they shine? What is it that makes some animals’ eyes, such as cats, dogs, deers and horses glow in the dark?
Well, because I’m A Useless Info Junkie is here to give you the answers for all those overlook features of our everyday life, here’s how it goes.
Nocturnal animals (those who go out at night) have a white guanine compound called tapetum lucidum in the retina. This substance is actually reflective and provides a mirror-like surface that actually reflects incoming light back towards the front so that animals can have a second chance in seeing what’s happening in the dark in case the photoreceptor that’s responsible for transmitting the information to the brain was not hit the first time. This of course, helps these animals see better during the night when the light conditions are very low. But why not all animal’s eyes glow the same color? (the article continues after the ad)
According to Colorado State University’s ophthalmologist Dr. Cynthia Powell, this is due to different substances (such as zinc or riboflavin) in an animal’s tapetum, as well as varying amounts of pigment inside the retina. Age is also partly responsible for the glowing color and that’s why some animals. despite being of the same species, have eyes that may glow in different colors.
Tapetum lucidum can be found in a large number of animals, including cats, dogs, deers, ferrets, cattle and horses.