Why a Cat's Eyes Are so Fascinating

My cat likes to go out and play in the evening, before the household settles down for the night. If one of us hears a muffled "meow" at the door before we call Tweeters in; we open the door very carefully. We do this, because chances are that he has a mouse that he wants to share with us, and we don't particularly want him to share.

Have you ever wondered how it is that a cat can see so well at night, that he can catch prey? Or, have you ever walked into a dark room, only to have two eyes shining up at you; scaring the dickens out of you? Better yet, have you seen your cat leap large distances, to catch a prey, when you saw nothing move at all?

There are so many things about a cat's vision, and the way that their eyes work, that is absolutely fascinating. These attributes of a cat's vision will help you to understand how a cat's eyes work, and how their vision allows them to do such spectacular things.

1. Cats eyes have a Tapetum Lucidum

The tapetum lucidum is a layer of tissue that cats have in the back of their eyes, that reflects light back through their retina, increasing the amount of light that they have to see with. A cat's eyes see light that a humans eyes do not see. This tapetum lucidum is also what makes your cat's pupils appear to glow in the dark.

For a bit of trivia; the earliest patent, first used in "Catseye" brand raised pavement markers, was inspired by the tapetum lucidum of a cat's eye.

2. In cat's eyes, size makes a difference

Because a cat has such large eyes, and their retina is so large compared to the size of the eye, they have better vision; especially at night.

3. Cats have a great field of vision

The reason for this, is because a cat's eyes are not pointed straight forward like a humans are. Humans have approximately a 180º field of vision, where a cat's is approximately 200º.

4. Cats are not color blind

Cat's eyes do not have a "fovea," like a humans eyes have. The "fovea" is what enables us to have sharp, central vision; which we need for any detailed activity. Though cats do not have this, their eyes have a central band known as a "visual streak" which does allow them to see some color.

5. Cats have a third eye lid

This third eye lid, is called a nictitating membrane, which closes from the side. This membrane can be seen when a cat open its eyes. A lot of times you can see it when the cat is just lounging around, sleepy and contented. The nictitating membrane is either transparent or translucent, and is drawn over the eye for protection, and lubrication; yet, while doing this, the cat can still see. It is for this reason cats do not have to blink their eyes as often as humans do.

6. Cat's eyes have rod and cone receptors

Cats have these receptors in their retina. The rod receptors are what gives cats their night time vision, and their cone receptors give them their day time vision. Cats have more rod receptors than they do cone receptors, and that is why they have better night time vision.

These points will help one to understand why a cat's eyes work the way that they do, and how they can hunt so well.

Resources:
http://en.wikipedia.org-Tapetum.lucidum
http://en.wikipedia.org-Night.vision
http://en.wikipedia.org-Cat.senses