The very idea of an electric fish seems like some outrageous science fiction creature dreamed up by... well, an author like myself. Even its scientific name sounds like science fiction: Electrophorus electricus. But, I assure you, this creature is real.
What the heck is an Electric Eel?
Well, for starters, it isn't an eel at all. The electric eel is actually a type of knifefish, which means it's more closely related to catfish than to eels. They live in dark, murky rivers in South America, including the Amazon.
These fish use their electrical superpowers in several fascinating ways, mostly for locating and then subduing their prey, typically smaller fish.
Electric eels are large fish, typically growing over six feet (2 m) long and weighing 44 pounds (20 kg). Like catfish, electric eels do not have scales.
Amazing Facts about Electric Eels
Obviously, we need to explore this whole electric thing, right? There's a lot here to consider, so I'll try to organize it logically.
First, how in the heck do these fish generate a voltage? Basically, the electric eel has an amazing nervous system. Its nervous system can synchronize the activity of a series of specialized, disc-shaped cells that produce electricity. These cells are contained within a specialized electric organ. Actually, there are three pairs of these organs, and the organs can make up to 80% of the animal's body!
The disc-shaped cells are called electrocytes, and they are lined up within the organs so that a current of ions can flow through them. When the fish's brain decides to generate a shock, it sends a signal through its nervous system to the organs. Without getting too technical, I'll just say that this signal causes a sudden switch in the organ's polarity, thus generating an electrical current. Think of the organ as a battery, which has a series of stacked discs that produce a current in a similar way.
You see, the eel must activate all the electrocytes at once for this to work. The problem is, these cells are at different distances from the brain. That's where the fish's amazing nervous system comes in... the system has a complex array of nerves that makes sure all the cells activate at the exact same time, no matter how far out they are! Mind boggling, if you ask me.
How powerful is the shock? An electric eel can generate up to 860 volts and up to 1 amp of current. Is that enough voltage to kill a person? Probably not, but it would be painful, and it could incapacitate a person long enough for them to drown. Such drownings have occurred, although they are rare.
To give you an idea of what the shock might be like, consider this story from Philip Stoddard, a zoologist at Florida International University in Miami. Philip had a five-foot-long electric eel as a pet in an aquarium. The eel's name was Sparky. One day Philip decided he wanted to reach into the aquarium and pet Sparky. Philip knew the risk, but he figured the fish was comfortable around him and wouldn't feel threatened (hmm... ).
So, he reached in and stroked the fish's back. You can guess what happened, right? The fish zapped him with 500 volts of electricity, more than four times the shock he would get by sticking his finger into a typical North American household socket (for various reasons, here in the US we use 110-volt outlets—actually they are closer to 120 volts these days—whereas many other countries use 220). Anyway, Philip got a powerful shock. His entire arm hurt for about an hour.
Check out this video about how electric eels can defend themselves with electricity.
Now that we've talked about HOW they produce electricity, let's explore WHY they do this.
Obviously, one reason is for defense against predators. An electric eel can actually kill an attacking caiman that is trying to eat it. Even if the predator isn't killed, it will immediately realize it has made a mistake and will back off. Or, it will be incapacitated long enough for the eel to escape (you might find this a little disturbing, but here is a video recorded by a fisherman who catches an electric eel, then a caiman tries to attack the eel as the guy is reeling it in... the caiman appears to be killed).
But the eel's use of electricity is much more complex than just predator defense. They use their electricity in multiple ways.
They use low voltages to sense their surroundings, kind of like an electrical version of sonar. Remember, these fish live in muddy, murky water, and they have poor eyesight, so this low-voltage sensory ability comes in handy.
They use high voltages in several ways.
High-voltage use #1: To detect prey. The eel can emit pairs of high-voltage pulses, 500 of these pulses per second. These pulses cause their hidden prey to involuntarily twitch. The eel can sense these twitches (remember that low voltage use described above?), allowing it to locate the prey animal.
High-voltage use #2: To stun or kill prey. Once the eel locates the prey, it emits even higher-voltage pulses at 400 pulses per second. This stuns the prey fish, and the eel can approach it and suck it into its mouth with one gulp.
One more interesting morsel about electric eels. An electric eel at the Tennessee Aquarium has its own Twitter account. Yes, you read that right. The fish's name is Miguel Wattson. The fish's tank is set up to constantly monitor its electrical output. Whenever Miguel Wattson gets excited and generates enough electricity, this activates a connected computer to send out a pre-written tweet, many of which are clever and fun. Here's an example:
You can follow Miguel's tweets here.
Here's an older one:
So, the Electric Eel deserves a place in the S.A.H.O.F.
(Stellar Animal Hall of Fame).
FUN FACT: The word stellar originated in the 1650s, as an adjective meaning "pertaining to stars or star-like." Beginning in 1883, it was used in a theatrical sense of the word star (as in the star of a play). In this sense, stellar meant "outstanding, leading." Eventually, people started broadening its use to refer to anything that was outstanding, such as, "The company thrived, due to stellar management."
So, stellar is another way to say awesome!
Everyone needs a creative outlet. That's why I write.