Watch this slow-motion video of attacking electric eels

Scientists have long known that electric eels can send out short pulses of electricity to sense their environment and also to paralyze their prey. But one researcher has recently discovered that eels can also use powerful electric pulses to attack or defend themselves while leaping out of the water. 

Neurobiologist Ken Catania has been studying eels for several years. In fact, he keeps at least two tanks of eels in his lab for observation. One day, while he was moving one of his larger eels — a three-foot eel — from one tank to another, the eel turned around and started aggressively swimming toward him and trying to leap up at him out of the water. 

This was behavior Catania hadn't ever seen before, so he decided to study it further. He gathered a series of props — a fake crocodile head, a fake human arm — and rigged the props with LEDs that would light up when the eels attacked. 

Video producer Emily Driscoll visited Catania’s lab to learn more, and filmed video of Catania’s eels attacking various props. 

“It’s very dramatic footage,” Driscoll says, “because the lights are going off and also the slow motion — you can really see how it climbs up. … One thing I was afraid about — I got to use the special Science Friday GoPro camera and we weren't sure if that would survive 600 volts of electricity.”

As Catania studied the phenomenon of attacking electric eels further, he uncovered some interesting historical precedent. 

In 1800, there is an account from German naturalist Alexander von Humboldt, who set out for an Amazonian lake to collect electric eels for his experiments, aided by a team of horses. As the animals entered the lake, Humboldt wrote the eels leapt up the legs of the horses to shock them. There were some 30 horses in the lake, and Humboldt said several of them were killed, likely after being stunned and then drowning. Humboldt wrote his account in 1807, and even then people didn't believe it. 

Now, Catania is able to prove the account was at least possibly true (and there's video to illustrate it.)

This article is based on an interview that aired on PRI's Science Friday.