Camels have three eyelids. This is a random fact I was given today by a friend who knows that I enjoy learning about weird and little-known things.

"Camels come equipped with 3 eyelids and this is predominantly for protection against sandstorms which can occur frequently in the geographical areas where camels are normally found.

The first 2 lids have very long eyelashes and these are used to keep sand from entering the eyes. The third eyelid is transparent and this allows the camel to see during a storm even when the eyelid is closed. Additionally, the third eyelid blinks in a sideways fashion (similar to windshield wipers) and this will clear away any sand currently on or around the lid." --http://askville.amazon.com/eyelids-camel/AnswerViewer.do?requestId=17394523

a duck also has three sets of eyelids.
"The reason ducks have 3 eye lids, In ducks the upper and lower eyelids have small bristle feathers that resemble eyelashes. They use the third eyelid for blinking."--http://www.chacha.com/question/why-do-ducks-have-3-eyelids