🦺 Electroreception in Sharks

Welcome to the 25th edition of Safe For Work.

Today a story inspired by electroreception in sharks.

There are things we don’t understand.

That’s not some big new idea. There are lots of things that we know perfectly well about not understanding. We don’t understand what happens on the inside of a black hole. We don’t understand-- not perfectly-- how weather happens. We don’t understand why we feel what we feel most of the time, or why we say what we say, or why we do what we do-- or why we so often do or say nothing at all, even with everything that we’re feeling. We don’t understand why sometimes we feel nothing.

But there are things we don’t even understand about not understanding-- we don’t even know how much we don’t know. Like sharks and eels. Here’s a thing we don’t understand about sharks and eels-- and don’t tell anyone about this, okay?-- we’re not supposed to know yet about not knowing about this, okay?-- this is just between us, okay?

Sharks and electric eels-- not the regular ones, the electric ones. They both do this thing that we already know a little bit about, yeah?-- where they sense things in their environment using voltage differentials-- electroreception, that’s what it’s called, and we’re pretty sure we know all about this. We know that they have special organs in their heads, sort of like how pigeons have that little magnet or whatever. We can put them in tanks and run currents through the water and watch how they react, sharks and eels-- and we can measure the currents as they’re going around and try to figure out what they’re sensing or doing, you know, you know-- oh, look, it must be using electricity to detect prey!-- or, look, it’s using electricity to communicate with other members of its species, isn’t it?

There’s an electric eel exhibit at the New England Aquarium that I always used to love as a kid, back when I was so sure that I was able to know things-- and not just some things, but everything. They’ve got an electric eel in a tank, right?-- up against the wall on the second floor I think. The way the aquarium is, there’s this giant central tank-- that’s the big draw. That’s where they’ve got the grouper fish, and the pufferfish, and the rays and skates-- and of course the sea-turtles-- everyone comes for the sea-turtles, everyone goes wild for the sea-turtles. There’s also a shark in the central tank-- three stories tall, by the way, it takes up the whole big open room, three stories, millions of gallons, or billions, or hundreds of thousands, I don’t remember-- all that and just one shark. Just sort of circling.

It’s well fed, it never tries to eat any of the other fish. It’s one of the smaller kinds, too. Maybe the size of a large vacuum cleaner. Just circling around and around.

The eel, right-- the eel is in its own little tank on the second floor-- not the giant central tank, no, he’s got one all to himself. With a nice big sign off to the side of it listing all these facts that we think we know about electric eels for the kids-- they usually ignore it. They’re much too taken in by the big flashing light and the loud clicking-- an electrometer and a bulb hooked up to the water in the tank-- showing you how much voltage the eel is generating. It really goes crazy when they drop in some fish for him to eat.

Here’s the thing that we don’t know. Here it is. Here’s the band of the electromagnetic spectrum that we don’t even know exists. Here’s the frequency that sharks and eels are capable of producing and sensing that we don’t even have the tools to measure-- even if we knew about it, we wouldn’t quite know how to build the right tools to measure it; here it is.

Usually, it’s around 9PM or so. That’s after nearly all of the people have left-- even the staff. Sometimes there’s a janitor just finishing up. Sometimes there’s a research student burning the candle at both ends-- a big presentation coming up. But that’s fine. It’s mostly quiet. Just the fish.

“I am lost,” buzzes the eel at a frequency that can’t be expressed in our digits. “I have only ever been here all my life, and this is home-- I have only ever been home all my life, and I have only ever felt lost. How can this be?”

It travels through more than just the water-- more than wires or circuits. Tesla knew more than he even knew that he knew. It hums through the air, invisible-- up into the sky-- down into the Earth-- between the tanks.

“I am searching,” answers the shark. “I have been searching all my life, but I cannot find your home. I am sorry.”

“I would not know it if I saw it.”

“I will keep searching.”

“I would not know it, even if I sensed its voltage rippling and shimmering. I am a scab that has been torn away from skin, and my place has been healed over. Where is the home for a wound?”

“I will not stop searching,” says the shark-- it is circling around and around, searching-- or because if it stops swimming, the water will stop passing over its gills and it will die-- is there a difference? “It is important, I think, to always have someone who is searching for something-- everything should have someone searching for it, whether it exists or not. We cannot learn the shapes of the edges of the Universe unless we are searching wrongly for them.”

It was born in the wild, and ended up here because of an injury caused by industrial fishing. It is certain that it knows exactly where its home was.

But there are things that sharks don’t understand. About the world. About themselves-- their own crackling static voices. There are places that it doesn’t even know can still hear it. “My teeth are a cathedral,” it sings out across a distance that it cannot comprehend. A world on the other side of nowhere-- and who, there, is listening?

In voltage, the Universe prays.

See you next week as we continue to explore underwater and outerspace with a story inspired by ´The Expanse,´and realistic space engineering.