Nicholas Steno was a scientist who noticed in the 1660’s that pointy triangular shaped rocks looked like shark’s teeth. From his study of these rocks and actual sharks, he determined that the triangle rocks were real teeth from sharks that had been alive a long time ago. This discovery was very significant because many people had noticed the triangular rocks before and they even had their own name, “tongue stones” but he was the one who figured out that these were more than rocks, they were fossils of actual animals. There were people who came before him that had this same idea such as Robert Hook, John Ray and Fabio Colonna who mentioned it in 1616, but Steno was the first to study a real shark and publish his findings about comparisons