Sharks Are Older Than Trees

When you think of ancient creatures, dinosaurs probably come to mind. But sharks are far older. Sharks have been swimming through the world's oceans for approximately 450 million years — predating dinosaurs by more than 200 million years, and predating trees by nearly 100 million years.

The oldest known trees date back to around 385 million years ago. These early tree-like plants, such as Archaeopteris, began to spread across land during the Late Devonian period. Before that, the land was covered mostly with low-lying mosses, ferns, and small shrubs — nothing that could truly be called a tree.

Sharks, meanwhile, had already been evolving in the oceans for tens of millions of years by the time those first trees took root. Fossil evidence shows shark scales dating back to the Ordovician period, around 450 million years ago.

Over the course of Earth's history, there have been five major mass extinction events — catastrophic periods when a large proportion of all species on Earth were wiped out. The most famous of these is the event that killed the dinosaurs, around 66 million years ago.

Sharks survived all five of them. While countless other species were completely erased from the planet, sharks endured. They outlasted the dinosaurs, the woolly mammoth, and thousands of other creatures that no longer exist today.

Sharks are built for survival. Their bodies are remarkably efficient hunting machines. Unlike most fish, sharks have skeletons made of cartilage rather than bone — lighter, more flexible, and requiring fewer minerals to maintain. This makes them highly adaptable to changing ocean conditions.

Sharks also have extraordinary senses. They can detect electrical fields produced by other animals — a sense called electroreception — which allows them to locate prey even in complete darkness or murky water. Their sense of smell is legendary; some species can detect a single drop of blood in an Olympic-sized swimming pool.

Despite surviving every mass extinction the planet has thrown at them, sharks now face a threat unlike any before: humans. Overfishing, shark finning, and habitat destruction have caused shark populations to plummet dramatically. Scientists estimate that over 100 million sharks are killed by humans every year.

A creature that has outlasted dinosaurs and survived five extinction events may finally meet its match in the modern world. Whether sharks will survive this sixth and very human-made challenge remains to be seen.