Fishes

Graphic of a shark pointing to different physical characteristics

What Makes a Shark a Shark?

Sharks seem to have it all figured out, evolution-wise. Fossils of prehistoric sharks go all the way back to 450 million years ago, and sharks like the ones we know today emerged about 200 million years ago. This means that they survived the mass extinction that took out the dinosaurs and lived long before early human ancestors evolved less than two million years ago. So, what makes a shark a shark? Here are just a few of its unique physical features:

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