Kim Mease, age 11, of Canton, N.C., for her question:
HOW DOES AN EEL GIVE OFF ELECTRICITY?
Eels are long, thin fish that look very much like snakes. Most of them live in oceans but many varieties spend a great deal of their time in fresh water. They usually grow to be about three feet long, but some can be found as long as six feet. Both the European eel and the American swim from fresh water streams to breeding grounds around the Bermuda Islands
Electric eels belong to a family called Gymnotidae and they are not true eels. They are actually related to the carp and catfish and are only called eels because they have snaky bodies. True fresh water eels belong to a family called Anguillidae.
A strong electric shock can be given by an electric eel. He usually lives in the muddy, shallow waters of the Orinoco and Amazon rivers in South America.
An electric eel's head is quite flat and his eyes are far forward and very close to his mouth. Most of his organs are in the front fifth of his body with the rear four fifths mainly holding the organs that make his electric current.
In the rear part of an electric eel's body are many layers of tissue, built one behind another very much like the plates in a storage battery. The current produced in these tissues flows from the head to the tail.
Scientists believe that a number of the swimming muscles in the electric eel's ancestors changed through the years into electric organs.
An electric eel has three pairs of electric organs. One pair, the longest, runs almost the full length of the body to the tip of the tail. Two shorter pairs are found under the long pair.
An electric shock is used to protect the fish from his enemies and is also used to catch food. The eel can also use the electricity to detect objects at a distance under water.
When an electric eel becomes excited, he can produce strong shocks in sets of three to five. Although each impulse lasts only a fraction of a second, an eel can keep them up for hours at a time. The electrical shock can reach between 200 or 300 volts, a jolt that could certainly stun a man if he came into contact with the fish.
Some eels have been known to discharge between 500 and 800 volts.
The electricity produced by an electric eel usually damages his own eyes, and then he uses a telegraph system to take the place of eyesight.
Often the weak shocks of an electric eel serve as a warning to his enemies, since they know that the weak shocks build to stronger ones.