Sharks Teeth
A shark often survives but only as fossils in its teeth! Sharks teeth fossils are sometimes as ancient as millions of years old. The most common of them are from the Cenozoic Era, i.e., around 65 million years ago, but rare ones have been found belonging to even 450 million years ago. Their teeth do not come out of their jaws, but are embedded in their flesh only, having multiple rows of them getting replaced every 8-10 days in some varieties of shark.
