How shocking: Electric eels are actually sophisticated hunters

When you think of nature’s greatest predators, the electric eel probably isn’t one of the species that typically comes to mind. But new research conducted by biologists at Vanderbilt University suggests that it may be time to give this remarkable hunter a little more credit.

Writing in the October 29 edition of the journal Current Biology, biological sciences professor Kenneth Catania revealed that the up-to-eight-foot long, 40-plus pound Electrophorus electricus possesses a secret weapon: a special technique that allows them to double their electrical shock simply by curling their bodies.

Catania, who has been studying this reclusive South American fish species over the past three years, explained that two thirds of the eels’ bodies are filled with electrocytes, a special type of cell that stores electricity. When threatened, these “biological batteries” can discharge at the same time, giving off at least 600 volts, or five times that of a standard US wall socket.

Typically, electric eels subdue feeder fish by firing off a series of Taser-like pulses which cause muscle contractions throughout the entire body, paralyzing them and making them easy prey. However, as the study author explained in a statement, they use a different plan of attack when faced with larger, more difficult prey.

Pulses can also be used to find and track prey

According to Catania, when pitted against something like a large crayfish, an eel will begin by biting its prey. Next, it will curl its tail around its victim’s body until the tail lies directly across the body from the eel’s head. This brings the positive poll of the electric organ in its head close to the negative pole in its tail, allowing it to increase the damage of its shocks.

Catania conducted several experiments and found that this technique more than doubled the strength of the electrical pulses delivered to the victim. Not only does this paralyze the larger prey similar to the feeder fish, but the increased power and higher pulse rate also caused their muscles to become fatigued, causing an effect similar to that of the paralytic agent curare.

“Historically, electric eels have been viewed as unsophisticated, primitive creatures that have a single play in their playbook: shocking their prey to death,” the VU professor said in a statement. “But it turns out that they can manipulate their electric fields in an intricate fashion that gives them a number of remarkable abilities.”

In addition, he found that eels use their electrical pulses to scan for potential victims in muddy waters, and utilizes their electric discharges like a precise radar system that allow them to track fast-moving prey. “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,” Catania said.

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