Nature Fact: Sea Turtles

Sea turtles have 3 eyelids. A lower eyelid, large upper eyelid, and a third clear eyelid called a nictitating membrane. This allows for protection of their eyes against sea water, scratches, and debris while allowing them to see clearly underwater. In addition, each eye contains a lachrymal gland, which secretes a clear substance similar to tears that helps clean the eyes, and allows the turtles to remove their systems of excess salt.