cat cats logo
Celebrating Felines
Save Up To 50% Everyday!
home   Home
Crazy for Kitties (Cats and Kittens!)
your cats   Your Cats
All our previous Kitty Stars of the Week. Contact us to have your cat be the star!
t-shirts   Cat T-Shirts
T-Shirts and Sweatshirts for you or your favorite cat-ophile.
names   Cat Names
Need a suggestion? Vote for your favorite name!
contact   Contact Us
Drop us an email
stories   Crazy Cat Stories
Because every cat has a story... Whitney
tales   Cat Tails
Share a cute story about your kitty. (Moderated)
articles   Features
Our feature articles...
books   Books and Music
Informative books,books of photos, books for kids. Plus music for your kitty.
facts   Kitty Facts
Do you know your kitties? Check out these cat facts.
quotations   Quotations
Celebrating cats through words.
gallery   Photo Gallery
Some great cat photographs to enjoy.
friends   Cat Friends
Gus, Kitty Baby Gram, plus kittens... and the Crazy for Kitties Mailbox
glossary   Meow!
Glossary of cat-related terms
links   Cat Links
Search our directory -- suggest a site! (Will open in new window.)
ricki   Ricki at 17
A little slideshow in memory of the Rick cat.

Copyright 1999-2018 by crazyforKITTIES (SM) Privacy

Why do cats' eyes contract to a vertical slit?:

Cats evolved to be nocturnal hunters, and they can see well in very dim light. Because their eyes are so sensitive to light, cats need precise control over the amount of light reaching their eyes.

Being able to reduce the pupils to slits rather than tiny circles gives the cat greater and more accurate control of how much light enters their eyes; this ability is particularly important in bright sunlight.

Vertical slits also have an advantage over horizontal slits. Because the cat's eyelids close at right angles to the vertical pupil, the cat can reduce the amount of light even further by bringing its eyelids closer and closer together. This combination of the vertical slits of the pupils and the horizontal slits of the eyelids, allows the cat to make the most delicate adjustments of the light reaching its eye compared to any other animal.

The pupils of the lion are an interesting comparison. The lion hunts by day, not by night as the cat does. The lion does not have the same sensitivity to light as the cat. And the lion's eyes contract -- like ours do -- to tiny circles, not vertical slits.

Source: Catwatching, by Desmond Morris, Crown Publishers, Inc., New York, 1986, p. 85.