David Barkalow, age 11, of Hobart, Ind., for his question:
WHERE DOES THE ELECTRIC EEL GET HIS POWER?
The electric eel is one of 50 or so gymnotid fishes of South America. None of them is a genuine eel, though most of them have shocking electric organs of some sort. The adult electric eel is a 6 foot whopper with a snakey body. His electric organ can generate a shock of 550 volts, which is powerful enough to stun a horse.
Electrical energy is carried in the tiny electrons that orbit the nucleus of the atom. They can be tempted to leave home by heat, friction, a magnetic field or the interaction of certain chemicals. And when they depart, they carry their fantastic energy along with them. All living cells are powered by electrochemical energy, generated when chemicals free orbiting electrons.
The large, snake shape electric eel adapts this system to run a special powerhouse that generates stunning electric shocks. His head and internal organs are crowded into the front 9 inches of his body. His fantastic batteries occupy the 62 inch tail section.
This powerhouse is made of fatty tissue, crowded with 5,000 or so tiny electroplates, arranged somewhat like the cells in a dry battery. Scientists suspect that these stubby little cells are adaptations of the long nerve fibers that normally carry electric signals between brain and muscle.
Long nerve fibers normally trigger muscles to contract. In the electric eel, they trigger the electroplates to send current from cell to cell. When large numbers release their charges together, they generate a jolt strong enough to stun a human swimmer. A few quick jolts may be fatal, and the electric eel can shoot off dozens of shocks in a second.
His three part powerhouse consists of a main battery and two smaller ones. One small battery continuously sends out weak shocks, which echo back from solid objects. They help the electric eel to form a picture of his surroundings in the muddy water. Scientists suspect that his high voltage shocks are generated by the second small battery. Their purpose is to stun fishes and other animals suitable for food.
The long, lazy electric eel is at home in the muddy streams of the Amazon basin. He is distantly related to the catfish of North America, though nobody knows much about his family life. At certain seasons, the super shockers disappear from their favorite streams. Later they return, guarding their broods of 6 inch youngsters.