The electric eel has three abdominal pairs of organs that produce electricity. They are the Main organ, the Hunter's organ, and the Sachs organ. These organs comprise 4/5 of its body. Only the front 1/5 contains the vital organs.[1] These organs are made of electrocytes, lined up so that the current flows through them and produces an electrical charge. When the eel locates its prey, the brain sends a signal through the nervous system to the electric cells. This opens the ion channel, allowing positively-charged sodium to flow through, reversing the charges momentarily. By causing a sudden difference in voltage, it generates a current. The electric eel generates its characteristic electrical pulse in a manner similar to a battery, in which stacked plates produce an electrical charge. In the electric eel, some 5,000 to 6,000 stacked electroplaques are capable of producing a shock at up to 500 volts and 1 ampere of current (500 watts). The organs give the electric eel the ability to generate two types of electric organ discharges (EODs), low voltage and high voltage. The shock could be harmful for an adult human. The Sachs organ, not to be confused with the sex organ ;-), is associated with electrolocation. Inside the organ are many muscle-like cells, called electrocytes. Each cell can only produce 0.15V, though working together the organ transmits a signal of about 10V in amplitude at around 25 Hz. These signals are what is thought to be used for communication as well as orientation; useful not only for finding prey, but also in finding and choosing a mate. EODs are emitted by the main organ and the Hunter's organ that can be emitted at rates of several hundred Hz. These high voltage EODs may reach up to 650 volts. The electric eel is unique among the gymnotiforms in having large electric organs capable of producing lethal discharges that allows them to stun prey.[2] There are reports of animals producing larger voltages, but the typical output is sufficient to stun or deter virtually any other animal. Juveniles produce smaller voltages (about 100 volts). Electric eels are capable of varying the intensity of the electrical discharge, using lower discharges for "hunting" and higher intensities for stunning prey, or defending themselves. When agitated, it is capable of producing these intermittent electrical shocks over a period of at least an hour without signs of tiring. The species is of some interest to researchers, who make use of its acetylcholinesterase and ATP. The electric eel also possesses high-frequency sensitive tuberous receptors patchily distributed over the body that seem useful for hunting other Gymnotiformes. http://en.wikipedia.org/wiki/Electric_eel