Featured Image Credit: AAAS
By: Alice Morris
Research out of Vanderbilt University has identified a new behavior in electric eels that may shock you. Literally.
While studying eels in his lab, biologist Kenneth Catania made a fascinating discovery as he was transporting individuals out of their tanks. Instead of dodging Catania’s nets, the eels attacked, jumping out of the water to lunge at the net handles and deliver high-voltage shocks directly to the perceived threat.
Catania was wearing rubber gloves at the time so he didn’t receive an electric shock, but after witnessing several similar attacks, he started digging to find out what the eels were doing.
As it turns out, this jumping behavior was observed over 200 years ago by the Prussian explorer and naturalist Alexander von Humboldt as he traveled through South America. Humboldt witnessed local fishermen collecting electric eels by herding horses into eel-infested waters and allowing the eels to shock the horses until they exhausted themselves and could easily be plucked from the stream.
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It was a disturbing tactic to say the least, but it was Humboldt’s tale of the eels leaping out of the water to attack that captivated the public and contributed to his subsequent fame.
Humboldt’s recount eventually lost credibility, as further sightings of these leaping eels went unrecorded. But with Catania’s recent observation came the opportunity to validate this centuries-old tale.
Using a voltmeter hooked up to an aluminum plate, Catania was able to measure the strength of the eels’ electric shocks. He found that, while submerged underwater, the power of the shocks dissipated quickly, but when the eels jumped out of the water to attack, they could deliver a far more powerful shock directly to the target. It’s an effective strategy, but what makes these animals choose fight over flight when confronted with a threat the size of a horse?
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The answer may lie in the seasonal changes that electric eels face in the Amazon. When water levels are low and eels are living in very shallow pools, it may become more beneficial to attack predators rather than risk being eaten. For many eels that breed during the dry season, this also serves as a proactive defense mechanism to protect their young.
The discovery is an exciting development for researchers and will hopefully lead to a greater understanding of these electrifying animals.