Q1543Sharks have swum the oceans for more than 400 million years — appearing before the first trees grew, and possibly before Saturn's current rings formed.
Sharks arose over 400 million years ago, while the earliest true trees came later, around 380 million years ago. Saturn's bright rings may be younger still — some evidence suggests the current ring system is only a few hundred million years old, so dinosaurs might have looked up at a ringless Saturn. Sharks have outlasted several mass extinctions, quietly persisting while the world rearranged itself around them.





