Buzz
Never corner an electric eel. These serpentine fish can lift themselves out of the water to deliver a stronger electric shock when they feel endangered. Kenneth Catania, a biologist at Vanderbilt University, details this behavior in a study published in the Proceedings of the National Academy of Sciences.
Reports of eels leaping from water aren’t new. In the early 19th century, naturalist Alexander von Humboldt documented a South American fishing method called 'fishing with horses.' Fishermen would drive horses into eel-infested waters, provoking the eels to jump out and shock the horses. This drained the eels' electric charge, allowing fishermen to easily collect them.
Image Credit: Robert H. Schomburgk // Public Domain
"When I first encountered von Humboldt's account, it struck me as utterly peculiar," Catania remarked in a press release. "Why would the eels target the horses instead of simply escaping?"
Many contemporary biologists shared this skepticism: They believed von Humboldt’s description of leaping eels was likely an exaggeration, much like other fantastical accounts from early naturalists.
However, the eels themselves debunked this assumption. Catania, who studies electric eels—despite them not being true eels—in his lab, was observing their hunting behavior. To examine an eel closely, he used a net with a metal rim to transfer it from its tank.
"In retrospect, using that net design with electric eels wasn’t the wisest decision," he admitted.
This oversight, however, led to a startling discovery: "Initially, the eels would retreat but then suddenly launch an aggressive attack as the net drew near," Catania notes in his study. "They would swiftly swim toward the net, follow the metal rim to the water’s surface, and leap upward along the rim and handle, maintaining contact with their chin while releasing high-voltage shocks. This behavior was both astonishing and electrifying." Thankfully, he was wearing insulated rubber gloves.
Despite his observations, Catania remained puzzled about why the eels chose to exit the water rather than flee. To investigate, he conducted experiments using two simulated threats: a plastic alligator head and a fake human arm equipped with electrical sensors to mimic human nerve responses.
You can witness the outcomes of these experiments here.
The findings revealed that the eels leverage natural principles to enhance their electric shock capabilities. By emerging from the water and pressing against their target, they redirect the electrical current, which typically disperses into the surrounding water, directly through the attacker.
"This adaptation enables the eels to deliver the strongest possible shocks to partially submerged land animals encroaching on their territory," Catania explained. "It also ensures that a larger portion of the intruder’s body is electrified."
But why do eels choose to shock rather than retreat when threatened? Catania proposes that escape is often impractical, particularly during the dry season when eels are confined to small pools. As he puts it in the video: "In essence, you’re dealing with a living, breathing electric fence."
