Science isn’t always just swanning around with test tubes in a shiny air-conditioned laboratory. Quite often, knowledge has to comes from suffering. For example, the entomologist who stings himself with insects to document their toxicity and pain.
Now, taking up this mantle, a biologist has let an electric eel shock him in order to document the sensation of the electrical jolt and understand the flow of electricity. His valiant efforts were made as part of a new study in the journal Current Biology. He also filmed the experiment (video below) for your viewing pleasure.
It turns out, it hurts a fair amount. The recordings showed that the eel can spark an electrical current of 40-50 milliamps. While that isn’t enough to kill a human or most animals, it’s enough to give them a pretty unpleasant zap, sufficient enough for them to back off.
"It's impressive that a little eel could deliver that much electricity," explains Kenneth Catania of Vanderbilt University in a statement. "We don't know the main driver of the behavior, but they need to deter predators, and I can tell you it's really good at that. I can't imagine an animal that had received this [jolt] sticking around."
Scientists have known for hundreds of years that electric eels leap out of the water to shock their enemies. Famed philosopher and scientist Alexander von Humboldt noted this behavior around 200 years ago, after witnessing a battle between electric eels and horses in the Amazon. Catania says that "no one really necessarily believed it, or if they did, they thought it was just kind of weird." Whatever they thought, it was more or less forgotten.
Catania has previously studied this leaping technique and showed how it helps keep the eels' electrical discharge nice and strong by ensuring it doesn’t dissipate through the water. His latest experiment was to try and learn more about the circuit of electricity that the eel creates by leaping out of the water. Unfortunately, he had to become part of that electrical circuit. He developed a specialized piece of equipment that accurately measures the strength of the electric current through his arm.
Through this interface, he is able to understand how powerful the shock will be based on the size of the eel and the circumstances of the shock.
"We've known these animals give off a huge amount of electricity, and everybody thought that was really amazing," Catania says. "But they aren't just simple animals that go around shocking stuff. They've evolved to produce stronger and stronger electrical discharges, and in concert they've evolved these behaviors to more efficiently use them."