Per the BBC, researchers have demonstrated that sharks (in this case, lemon) learn from the behaviors of their fellows. It's the first study to demonstrate social learning in any cartilaginous fish.
"The results showed that sharks working with trained partners could complete tasks more quickly and successfully."
There's a cool embedded video that shows the experiment.
I'm reminded of a National Geographic article from the mid-2000s about breakthroughs in great white shark studies, where scientists were tagging them with satellite trackers and such. The neatest—and by "neatest", I mean "most absolutely terrifying"—thing was a little throwaway anecdote about how the sharks would stick their heads out of the water for extended periods of time, and just languidly...watch...as the scientists did their work.
Great whites would pop up.
For extended periods.
Serene as you please.
Then sink back beneath the waves.
And then appear later.
Over and over and over again.
WHAT ARE THEY LEARNING?!!! WHAT ARE THEY THINKING?!!! GAHHHHHH!!!