Electric eels have long been known to deliver low-voltage pulses as a form of natural sonar—but now researchers out of Vanderbilt University have discovered the eels also deliver high-voltage shocks, which they use to paralyze their prey—from a distance, with no physical contact—in just three milliseconds. It's the first known case of an animal remotely controlling another via electricity, reports National Geographic. "Apparently, eels invented the Taser long before humans," biologist Kenneth Catania, who published his findings in Science, tells Reuters.
Electric eels (which have a deceiving nickname—they're not eels at all but serpentine-bodied knifefish native to the Amazon and Orinoco Rivers in South America) can grow up to 8 feet in length. Their electric organs generate up to 600-volt charges that match the electric pulses from their prey's nervous systems, allowing the eels to remotely activate their prey's nerve cells, which in turn control muscles. When an eel sends out the quick, high-voltage pulses, the muscles of the fish it is targeting contract strongly, basically crippling the fish even though there is no physical contact with the eel. The eels can also use electric pulses to force the muscles of nearby fish to twitch, thus revealing their prey's location. (See how old the oldest known eel in the world was when it recently died in the bottom of a Swedish well.)