Sam and I know that we have a third eyelid and that humans don’t! However we did not know that there were quite a few animals that have a third eyelid! Animals such as the polar bear, shark and aardvark are just a few. Sam and I thought that you might understand how the third eyelid is used by our below examples of the bird, llama and camel.
Birds have three eyelids; one upper, one lower and a nictitating membrane between the two eyelids. This membrane is operates like our tear duct does. It cleans and protects the bird’s eye. It is transparent, so that the bird’s vision is not impaired. Some veterinarians think that the third eyelid covers the bird’s eye when they are flying. In other words it’s like they are wearing birdie goggles to prevent dry eyes!
Both the llama and the camel have a third eyelid. The membrane keeps the sand out, yet they are able to see through the lid. Therefore both the Llama and Camel can literally see through a sandstorm!
This informative link from Wikipedia will also show you some interesting insight and pictures of the third eyelid!
http://en.wikipedia.org/wiki/Nictitating_membrane
Remember to Hug your Animals,
Maggie & Sam
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