Possibly no other creatures are as mythologized — or as misunderstood — as sharks. Blockbuster thrillers and sensationalized media have fueled the belief that sharks are monsters: unthinking, bloodthirsty, vengeful, and primitive. While they are ancient creatures, having emerged long before the first dinosaurs, after 400 million years the 500 or so known shark species have adapted to their ecological role.
Sharks’ adaptations include light, flexible skeletons of cartilage, teeth replaced without limit, and skin covered by a hydrodynamic surface of tiny tooth-like structures. Their keen senses include one that detects electrical signals given off by prey and enables navigation by Earth’s magnetic field. Their nervous systems are also adapted to sense minuscule water movements, such as the struggles of a far-off fish.