Cats, our feline companions have an extra pair of eyelids which remains hidden but show up occasionally. Ever wondered what it is? Well, It is a white pinkish membrane located at the corner of the ...

A cat's third eyelid, or nictitating membrane, is typically not visible unless there is an issue. Common causes for the appearance of the third eyelid include sleepiness, sedation, or medical ...

Felines have a third eyelid (nictitating membrane, nictitans, haw) arising from the corner of the eye nearest the nose, which is a white to pale pink pliable, thin layer of conjunctival tissue located ...

The nictitating membrane of an American robin is revealed while eating cherries at E.T. Mahoney SP. Since fish have fluid constantly cleaning debris from their eyes, their use of eyelids for this ...

University of Bristol provides funding as a founding partner of The Conversation UK. Our family dog used to have a rather noticeable extra eyelid that became especially apparent when he dozed off, ...