Older Than Trees

Sharks were already hunting the oceans before the first tree grew, before dinosaurs, before any animal crawled onto land. Their 450-million-year lineage has survived all five of Earth's mass extinctions by repeatedly refining a body plan that works.

That design is built for efficiency: a skeleton of cartilage, lighter and more flexible than bone, plus skin covered in tiny tooth-like scales that cut drag as they swim.

There are over 500 species alive today, from the dwarf lantern shark that fits in your palm to the school-bus-sized whale shark that strains plankton from the water. Most are small, harmless to people, and quietly hold their ocean's food web together.