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You Little Stunner

You Little Stunner

By Gavin Hammond

It is widely acknowledged that of the 40,000 species of fish residing in the seven seas, none have fingers, despite what certain frozen food companies would like you to believe. (The author can also confirm that chickens do not have nuggets). There are, however, some deep dwelling predators that prefer to fry their food before dining; one such culinary creature is Electrophorus electricus, otherwise known as the electric eel.

An electric eel is capable of producing one amp of current driven by up to 750 volts - enough to strike down eight people. This large electrical current is used for navigation, communication, attracting a mate and to stun or even kill prey.

"If an electric eel wanted a hot meal, it could generate enough electricity to power a microwave."
But how is this possible without the eel zapping itself in the process? Especially considering that the electricity is in direct contact with that well-known electrical conductor, water?

Along with electric catfish and electric rays, the electric eel, which is not actually an eel but a knifefish, possesses internal electric organs (slightly different from the dual-keyboard Hammond B-3 that your grandad used to play). These organs consist of a series of electric cells know as electroplaques, which are stacked in rows. (click for diagrams of the electric organs and electroplaques)

The current flowing through each row of electroplaques is just 1/7000 amps and the shock generated is only short lived. So individually each row doesn't produce enough current to cause the eel to hurt itself. Even its supper would to be a little rare. However, if an electric eel wanted a hot meal, by using all its 140 rows simultaneously it could generate enough electricity to power a microwave.

It's still unclear how the eels manage to survive their own shocks.  Two electric eels have been known to electrocute the same prey animal without shocking each other and some of the strongest bursts of electricity are released during mating, yet the eels remain unharmed. However, the same eels could fight to the death using identical shocks to those during the mating ritual.

How the fish are seemingly able to tolerate large currents at certain times and not at others is a mystery which still eludes research scientists. The answer may lie partly in a thick layer of fat which behaves as an electrical insulator, protecting the eels from their own shocks and, to some extent, the shocks of others.

When agitated, an electric eel can produce electric shocks intermittently over a period of at least an hour without showing any signs of tiring. A current of 0.93 amps driven by 750 volts provides around 698 watts of power, so just a couple of overwrought electric eels could boil your kettle.
Perhaps we should be farming them as a renewable energy source; then again, maybe they've got bigger fish to fry.


  • Studying electric eels helped Alessandro Volta to invent the electric battery in 1800.
  • Electric eels can swim forwards and backwards with equal ease, using their electric fields to navigate around.
  • Constant exposure to their own electrical fields causes the eels to go blind as they get older.
  • Since they live in very oxygen-poor waters, electric eels must regularly gulp air from the surface. An eel will drown if it doesn't surface at least once every twenty minutes.

For more from Gavin, visit his page.

And if you liked this, you might also want to try:

- Straight - Relativity works!
- Spoof - Scotland in whale bomb alert
- Reviews - The electric universe
- How does that work? - Batteries

For more information about electric eels try Melissa Ingalls' page here.

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05 Aug 2011
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