Aquila Children's Magazine The Electric Issue - Page 12

SHOCKING SPECIES Electricity is a naturally occurring form of energy, so it comes as no surprise that animals have been using it to their advantage for millions of years. Lots of different species have evolved to use electricity, but how did that happen? All muscles and nerve endings have the potential to create an electrical charge. This is how messages are transported back and forth from the brain. Every movement your body makes generates a small amount of electricity. Around 100-200 million years ago, some fish began to evolve this potential and developed specialised cells called electrocytes from their normal muscle cells. These are able to generate a much higher voltage than is needed for simple muscle movement. Depending on the species, these cells can be used for communication, navigation, as a method of defence, or to bag themselves a tasty meal! Electric ray In addition to being able to detect the electrical fields of their prey, some rays can also produce and use their own electricity. There are 69 species of electric ray living across the world’s oceans, generating anywhere between 10 and 220 volts – but not all of these rays use their power for hunting. Instead, species like the lesser electric ray (Narcine bancroftii) use it only to defend themselves against predators. Electric rays will also use their electric abilities to find mates and communicate with each other. IN THE OCEAN Sharks and stingrays Positively charged sodium ions are found in every cell in the body. They are the key ingredient for transmitting nerve impulses and sending messages to the brain. The sea, being so salty, is full of sodium chloride (sodium and chlorine – aka table salt) as well as other essential minerals and ions. This extra salty environment has allowed sharks and stingrays to develop a super sixth sense called electroreception. All animals have their own electrical field. Sharks and stingrays have hundreds of special pores around their faces. Filled with electrically charged jelly, they act as homing beacons, locking onto their prey with precision even in the darkest of waters. These pores are called Ampullae of Lorenzini and they look like black specks dotted around the mouth and nose, helping to locate even the trickiest of prey – even when it is hidden under the sand! (TOUGH SCALE) 12