How Strong Is a Zap From an Electric Eel? Shockingly Strong

A biologist learns an eel’s power first hand, allowing himself to be repeatedly shocked in the name of science

Biologist reaches into electric eel tank, comes out with equation to measure shocks

Few people would consider willingly getting shocked by an electric eel, but one bold biologist subjected himself repeatedly to the zaps in the name of science.

"We've known these animals give off a huge amount of electricity, and everybody thought that was really amazing," Kenneth Catania of Vanderbilt University says in statement. "But they aren't just simple animals that go around shocking stuff."

In research published last year, Catania demonstrated how eels could leap out of the water to channel their shocking power into whatever they were attacking. The study made use of props like fake human arms or crocodile heads to inspire the leaps. But props wouldn't cut it for his latest work, published last week in the journal Current Biology. He wanted to measure just how powerful of a punch these creatures can pack with their jolts—and so he did so using his own arm.

Electrophorus electricus, which is technically an electric fish not an eel, creates its infamous electric charge with three large organs in its long body, notes Jake Buehler for Gizmodo. "Electrocyte" cells in these organs create charges by moving sodium and potassium around, and the eels can trigger these shifts at a moment's notice to send the charges from thousands of electrocytes pulsing out of their bodies into an object or creature.

Catania first measured the eel shocks with a metal plate connected to a probe that detects electric current, reports Nell Greenfieldboyce for NPR. He realized that the voltage delivered to the plate seemed to increase with the height of the eel attack.

Electric eels, however, aren't normally shocking metal plates in the wild, so to get a more accurate sense of the current delivered, Catania needed to measure the eel's punch through living flesh.

Catania held a device to measure each jolt and then allowed a relatively small, foot-long eel shock him multiple times. He was curious to see how intense the electric current could get and how it varied, reports Ben Guarino of the Washington Post. The eel was able to deliver up to 40 or 50 milliamps at its farthest out of the water, with the height on his arm above the surface acting like a switch that could raise or lower the power.

"It's impressive that a little eel could deliver that much electricity," Catania said in a statement. These shocks were nearly ten times as powerful as a taser, and electric eels can get much larger in size with even more powerful shocks that can be lethal to animals.

He's hoping now to learn more about these electrifying fish, including how they're able to shoot out so much electricity without zapping themselves, and what exactly causes them to leap and attack.

"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," Catania says in a statement. "I can't imagine an animal that had received this [jolt] sticking around."

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