The electric eel employs a variety of highly charged tricks to track and subdue prey. Photo by Kenneth Catania/Vanderbilt
NASHVILLE, Oct. 29 (UPI) -- Prehistoric and one-dimensional -- that's the knock on electric eels. At least according to Kenneth Catania, a Vanderbilt biologist who says there are people who talk smack about eels.
"Historically, electric eels have been viewed as unsophisticated, primitive creatures that have a single play in their playbook: shocking their prey to death," Catania said in a recent news release.
According to Catania's latest research, electric eels use their charge in a variety of ways. When facing more formidable prey, like a large crayfish, the electric eel uses a more powerful shock maneuver.
With the prey in its mouth, the eel curls its body around so its tail is just inches from the prey. The horseshoe or circle-like shape, with two poles of the eel's charge now closer together, enables an electric charge twice as powerful.
Electricity acts on the prey's muscle-controlling nerves, not the muscles themselves -- but the muscles are what suffer. The super-shock technique generates enough electricity to overwork the prey's muscles to the point of exhaustion, all in a matter of seconds. Muscle fatigue leaves the prey helpless.
"The prey animals are completely paralyzed," said Catania. "The effect is comparable to administering a dose of a paralytic agent like curare."
Eels also use their electricity to scout territory in search of prey. Their eyesight is poor in the dark, muddy waters of the Amazon. By sending out slight pulses of electricity -- called doublets or triplets -- as they hunt, they can cause convulsions in nearby prey. Sensors in their head pick up the water movement as the prey briefly twitches.
When the eel finds prey, it then employs a high voltage discharge to track prey as they try to escape. Electrical feedback reveals the prey's trajectory.
"This dual use of the high-voltage system as both a weapon and a sensory system indicates that the eels' hunting behavior is far more sophisticated than we have thought," said Catania.
Catania's latest discoveries are detailed in a new paper published in the journal Current Biology.