The Atlantic Torpedo, Tetranarce occidentalis, and the Pacific Torpedo, Tetranarce californica, possess powerful electric organs that are strong enough to knock a man off his feet in certain circumstances.
At the New York Aquarium, we measured the electrical discharges of a large local specimen and found them to be about two hundred volts and 1600 watts. There is no doubt that such electrical powers are an excellent means of defense.
It is believed that torpedoes also use their electricity to obtain food, by stunning fishes and other creatures before eating them, because relatively large fish have been found in their stomachs without a single mark on their bodies. Only by shocking them into insensibility could the torpedoes have overpowered these fish without damaging them in any way. Moreover, a Neapolitan species of electric ray has been observed shocking mullet into insensibility and then swallowing them whole.
In appearance torpedoes are distinguished from other rays by their round, disklike body, large tail fin, and soft naked skin. Some of them are said to attain weights of two hundred pounds, but the average Atlantic torpedo weighs about thirty pounds. Weights of more than fifty pounds have been recorded for the Pacific torpedo. Torpedoes are born alive and are capable of producing electricity even before birth. There are quite a number of different kinds of electric rays, most of them found in tropical seas.