Prussian explorer Alexander von Humboldt wrote about a strange Venezuelan hunt in 1800. Villagers drove horses into a pond and watched them be shocked by electric eels until the current was exhausted, then they collected the eels (actually knifefish) to eat. His account was dismissed as a fish story by other scientists because they did not believe the description of eels reaching far out of the water to shock horses. I found it hard to believe that gathering eels was worth losing a couple of horses, but what do I know? Vanderbilt University professor Kenneth Catania doesn't know how true the story is, but he has done the research and indeed, eels will launch themselves high out of the water to attack in order to increase the shock value, as in the above video.
He has found that the eels can deliver a more concentrated shock by projecting out of the water and pressing their chins against animals. "The eels may not be very good at shocking something that's not fully in the water so this behavior is the solution,” he says. "The higher [the eel] gets, the more of that power goes through what it's touching and the less goes back through the water from its tail. These eels have evolved to have remarkable output, and it turns out they have evolved pretty remarkable behavior to go along with that."