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Electric eels use remote control on their prey

Electric eel (Electrophorus electricus).
[Credit: Kenneth Catania]

When an electric eel charges all its biological batteries, it can send out a 600 volt zap through the water. Impressed? What if we told you that it uses that power in a way that is even more...ahem...shocking? It turns out that the eels are using those zaps to remotely control the muscles of fish that they want to eat.

Kenneth Catania of Vanderbilt University put together a bunch of fish tanks, some hungry eels and some snack-able fish to figure this out. When the eels saw fish they wanted to eat, they released pulses of electricity that seemed to stun the fish in place and keep them from escaping. Catania wondered how the eels were forcing the fish to stay frozen. He discovered that the eel's electric pulses were sending a message to the nerves that control muscles in the fish, telling them to keep their muscles still. The eel's zap appears to copy the normal electrical pulses that fish nerves use to tell fish muscles what to do.

The eels can work a different kind of remote control on the fish as well, using a separate zap that made nearby fish have twitchy muscles. Those twitches could help hunting eels spot fish that might be hiding, Catania writes in the 5 December issue of Science. The eels also use low-voltage pulses as a kind of sonar to sense what else might be around them in the water.