Mulqueeny Eye Centers Friday Fun Fact

Why Do Animal's Eyes Glow In The Dark?

In some animals, especially those that go out at night, there is a reflective surface right behind the retina called the Tapetum Lucidum.  The purpose of this reflective tissue is to act like a mirror.  It reflects light as it enters the eye and allowing the rods and cones located in the retina another chance to pick up the limited amount of light available in dim lighting.

The Tapetum Lucidum is an adaptive feature that developed in animals who were hunters, primarily at night and early dawn when light is dim.  Dogs, cats, deer, cattle, horses are a few of the animals who possess this feature.  Humans (and some other animals) do not possess a Tapetum Lucidum because our retinas are designed for brighter light vision.

The other interesting fact about eye glow color or "eyeshine" as it is sometimes called, is that it is not the same for all species of animals and there are certain factors that can influence the color.  For example, age, color of the animal's coat and eye color as well as the amount of zinc and riboflavin present in the pigment cells with the Tapetum Lucidum can all play a part in the eyeshine color that we see at night.

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