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)
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