MadSci Network: Zoology

Re: electric eels - facts or fiction

Date: Mon Sep 10 11:24:44 2007
Posted By: David and John Free, Post-doc/Fellow, MFA, MFA
Area of science: Zoology
ID: 1187621837.Zo

Hello Tom
One of the best Electric Eel sites is the one run by National Geographic 
Here you can believe what is written.
These huge animals have special cells by the thousand that generate 
electrical voltages – up to 600 volts (which is 5 times the volts of a 
USA power socket.).
I think many people confuse volts with watts. 746 watts is the rate of 
doing work – and is actually one horsepower! A man, fully fit and trained 
might manage half a horsepower for a few minutes.. But no electric eel 
could manage 600 watts for over an hour. It is not a matter of “getting 
tired”, it is simply not having that much energy (work) to put out as 
electric energy or any other.  It would have to “eat like a horse!”

These animals live in fresh water – which is a poor conductor of 
electricity. So they can put out 600 volts without delivering much 
current (current times volts equals power, in watts). Also they have 
electric field  (volts per inch) sensors for strength and direction. So 
they can find their way around and locate friends, foes and mates 
electrically. For close-range work only a few volts are necessary and 
this works to let them “see” all around themselves in the muddiest water! 
It works because ANYTHING placed in the water alters the strength and 
direction of the local electric field.

To scare off a foe, or even kill them, the electricity must pass through 
a vital organ (say a heart or any such pumping device that is stimulated 
or triggered by the electrical signals of nerves). Thus an “eel fight” 
must be like a wrestling match; each struggling for body contact (as the 
bodies conduct well: the fresh water poorly).
When close enough (to get the water-resistance low enough) an eel can 
produce perhaps one ampere (in a pulse lasting say one second) . This is 
plenty enough to stop the heart or gills or lungs of its victim  (cardiac 
or respiratory failure and muscle paralysis).

A good book on Electric Eels and other creatures is:
Allen, Missy & Michael Peissel. Dangerous Water Creatures. New York: 
Chelsea House, 1992: 40.

And of course the Guinness Book of Records:-
Guinness Book of Records. New York: Bantam, 1992: 95.

I hope some of this has interested you: write back if you have other 

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