Do sharks have eyelids?

That’s one of the questions tossed about in a TV ad for a mobile phone that will not only make prank calls but will also tap into a wealth of internet information.

Only the ad never answers the shark question.

Ever curious, Pop Omnivore went to an expert to find out: Samuel Gruber, a shark biologist who teaches at the University of Miami's Rosential School for Marine and Atmospheric Science.

Here’s what he said: “Fish have no eyelids. Sharks have among the most elaborate eyelids and ocular adnexa in the animal kingdom. There are sharks that can close their eye in a way similar to ours. Others have a third eyelid. But some do not have eyelids. instead of closing eyes, they roll their eyes upward and backward to protect the delicate transparent cornea.”

Pop Omnivore was puzzled. But, um, aren’t sharks … fish?

Gruber was very kind about our ignorance. “Ah I see--you think sharks are fishes.  This is not so.”

Our eyelids are now fluttering like crazy. How can this be?

“Sharks are fish-like vertebrates but are as different from fishes as humans are from frogs,” says Gruber. “Sharks evolved from the jawless fishes as did the true bony fish about half a billion years ago but have been on an independent evolutionary track for lo these half billion years.  Thus sharks are in a different systematic order from fishes and are very different kinds of animals.

“So when I say fish have no eyelids I mean that bony fishes (Osteoichthyes) are lidless; in contrast sharks (Chondricthyes) have a variety of mobile lids not seen in the bony fishes.”

Now I don’t care how good a cell phone is. There is no way you are going to find out all that stuff by cruising the Internet!

Plus, Gruber totally made us feel better by adding: “I would hazard a guess that not one in 100,000 people knew that sharks are not true fishes!!”

-Marc Silver

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