At the forefront of hit movies like “Jaws,” “47 Meters Down” and “Sharknado,” sharks are often represented as fearsome, dangerous creatures — despite posing a statistically low risk to humans.

One of the most sought-after fossils is a megalodon shark tooth. The megalodon was a shark the size of a school bus and many of the teeth fill up the palm of a grown man. Emily Warner found one ...