Secrets of electric eels’ shocks unlocked

New York Times : Electric eels inspired the creation of the first batteries 200 years ago. Researchers have been studying eels every since, but they have not fully understood how the eels use their electricity. Now Kenneth Catania of Vanderbilt University and his colleagues have revealed some of the details of the eels’ strikes. Using cameras that capture 1000 frames per second, they recorded the eels attacking fish. That allowed the researchers to see the effect of the shocks—up to 400 per second—that the eels generated. They found that instead of immediately killing the target, the shocks stun the fish, causing it to stop moving within 0.04 s. While the fish is stunned, the eel swallows it whole. Further testing revealed that the shocks target the nerves that connect a fish’s muscles to its spinal cord. The electrical pulse triggers all those nerves and causes an immediate contraction in the muscles. That finding helped Catania and his team determine why eels sometimes fire two distinct pulses: When an eel is in murky water and its pulses hit a potential fish, the eel uses waves caused by the contractions to locate its prey.