Dear Matthew Alice: Why don't fish have eyelids? — D.D., El Paso, TX
Well, we've got ’em to help keep our eyeballs moist. Fish certainly don’t have that problem. They don’t sleep the same way we do, and they don’t have problems with blowing dust or sand. In short, fish don’t need eyelids (though sharks, skates, and rays have a clear eyelid-like structure). So to achieve a streamlined contour, which fish do need, eyelids are eliminated from the basic body design. As are ears, noses, hair, side-view mirrors, radio antennas, and chrome trim.