Sharks are older than trees

The first trees worthy of the name — real trunks, deep roots, forests — appeared around 385 million years ago. Sharks had already been in the sea for tens of millions of years: their oldest fossil scales and teeth date back some 450 million years.

Do the maths: sharks predate forests, predate the dinosaurs (who would take more than 200 million years to show up), predate flowers, mammals and anything that walks on four legs.

And they didn't just arrive early: they stayed. They have survived all five great mass extinctions, including the Permian one, which wiped out more than 90% of marine species. Their basic design has changed so little that a Jurassic shark wouldn't look out of place in a documentary today.

The scale is dizzying even within a single individual: in Arctic waters there are Greenland sharks swimming today that, according to the dating of their eye lenses, may have been born before the French Revolution.