How Animals Produce Electricity
There is an organ which situated in the tail section of a fish called the ‘electric organ’. In this organ, there are cells that are called ‘electrocytes’. These cells receive signals from the brain and produce electricity. In strongly electric fishes, the electric organ contains huge amount of electrocytes. This allows them to discharge high voltage electricity, sometimes as high as 600 volts. For weaker electric fish, they simply have a smaller electric organ, therefore producing a lower voltage of electricity. These fishes use electricity to paralyze or electrocute their prey, for self protection, for communication and for navigation. Click here for an animation showing how a fish uses electricity to navigate.
There are two types of discharges, the pulse type and the wave type. All strong electric fishes are of the pulse type which means they discharge short but powerful electrical pules at irregular intervals. For most weak electric fishes, the EODs (electric organ discharge) are very constant and continuous. However, when two fish with similar frequencies meet, confusion occurs which causes problems in electrolocation. To solve this problem, they will alter frequencies until they are able to recognize only their own frequencies.
Not only can these fishes produce electricity, they can also sense electricity from other creatures. They have a very sensitive organ called an ‘electroreceptor’ which is embedded in their skin. This organ picks up the slightest change of electric field caused by nearby objects. This allows the fish to feel the surrounding environment. This process is called ‘electrolocation’.
Not all types of fish can produce electricity. Some fish can only sense electricity. Some examples of these types of fishes are, sharks, rays, skates, catfish, and paddle fish. These fishes sense weak electrical fields from their prey and accurately locate the prey. This type of electrolocation is known as ‘passive electrolocation'.