"Conching” is a method by which Indo-Pacific bottlenose dolphins are trapping small fish in conch shells, bringing the shells to the surface, and then shaking them with their rostrums to clear out the water and dump the fish into their mouths. More remarkably, the trend appears to be spreading throughout an entire population of dolphins, and fast.
The first isolated instances of conching were recorded in 2007 and 2009 among a small group of Shark Bay's dolphins. But other dolphins seem to be observing that behavior and learning the method for themselves--in the last four months alone, researchers have documented the behavior six or seven times--marking a very rapid horizontal spread of behavior.
Link via Popular Science