The Insane Biology of: The Electric Eel

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They're at least A, if not S.

👍︎︎ 12 👤︎︎ u/According-Air6435 📅︎︎ Jul 31 2022 🗫︎ replies

As long as they stay restricted to the water realm I'm fine with them.

👍︎︎ 8 👤︎︎ u/SarpedonWasFramed 📅︎︎ Jul 31 2022 🗫︎ replies

Electric eels are easily S-tier. They have a broken sensory ability, hunt in both packs and as solitary critters, can punch way above their weight class if they have to.

But what moves them from high-A to low-S in my opinion is that they have two kinds of electrical pulses and are smart enough to use them in conjunction. The first stuns prey. The second one causes involuntarily muscle contractions. So even hiding in the soil or the surroundings doesn't work against a determined electric eel, they can just force you out of your hiding spot.

👍︎︎ 3 👤︎︎ u/Rofel_Wodring 📅︎︎ Aug 01 2022 🗫︎ replies

Tried out a knife fish build once and it’s not for me, but mad respect to the mad lads who turn a sensory upgrade into a deadly aoe

👍︎︎ 2 👤︎︎ u/Pallemand 📅︎︎ Jul 31 2022 🗫︎ replies
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In the rivers of the Amazon  rainforest is a fish like no other. A fish that you would not want to find  yourself wading in the water with. A specimen of this fish was brought to  Philadelphia from South America in 1773.   It was observed that: It had the extraordinary power of communicating  a painful sensation, like that of an electrical   shock, to people who touched it, and  of killing its prey at a distance.” It was a fish so unusual, that it would go on  to change the course of science - and in fact,   the course of modern society - forever. Electric eels are a genus of  freshwater fish from South America,   famous for their ability to stun their prey by  generating electricity, “Eel” is a misnomer, as   they are actually part of the knife fish family,  and are more closely related to catfish than eels.   And though they aren’t the only electric fish in  the world, they are by far, the most powerful.   Some individuals are able to deliver  shocks at up to 860 volts and 1 amp. The average shock from an electric eel  lasts about two thousandths of a second.   A single shock likely wouldn’t  kill a person, but it could   seriously stun one. If shocked,  your muscles would briefly contract,   and then you’d feel numb. If you were in the water  and got shocked, this could lead to drowning. It's one of only a few animals that can  kill its prey at a distance. And not   only can the eel use electricity to stun or  kill its prey - it can also use electricity   to control its target remotely - the  electricity coursing through the prey’s body,   making it act in a way detrimental to  itself, and beneficial for the eel. And as formidable a hunter as an electric eel is  on its own, recent studies have discovered that   they are not the solitary predators researchers  always believed them to be. They are in fact,   proficient and effective pack hunters,  ambushing schools of fish in terrifying unison. How is it possible for a fish to generate   so much electricity? And what has modern  science learned from this improbable creature? Electric eels live in streams, floodplains, and  swamps of the Amazon and Orinoco river basins   in South America. Such murky habitats can be  dangerously seasonal for a fish. During the dry   season, water levels drop, and oxygen availability  can plummet. But luckily for the electric eels,   they can breathe air, thanks to a special mucous  membrane in their mouth that can absorb oxygen. Electric eels are snake-like in  appearance, and they are pretty huge.   They can grow up to 8 feet,  or 2.5 meters in length,   and weigh as much as 44 pounds, or 20 kg. They  don’t have scales, and instead, have slimy,   dark gray or brown skin on the top of their body  and a yellow-orange color on the bottom side. And 80% of the eel's body,  by length and by weight,   is dedicated to one thing: generating  ridiculous amounts of electricity. The electric eel has three pairs  of electric organs that run through   the back portion of the its body: the Sach’s  organ, the Hunter’s organ and the Main organ. The Main and Hunters' organs are the high voltage  producers, used for protection and stunning prey.   The Sachs' organ is capable only of producing   low voltage pulses - its purpose is mainly  electro communication and navigation. These organs contain hundreds of  thousands of modified muscle cells   called electrocytes. These are flattened  disk-like cells that are stacked in about   70 columns on each side of the fish’s body.  Each column contains 5000–10 000 electrocytes. In their resting state, these  electrocytes maintain a negative charge   as the cells constantly work to pump positively  charged sodium and potassium ions out.   And each electrocyte is connected to the  nervous system - but on only one side. When the eel senses prey or a threat, it sends a  signal through the nerve endings causing an ion   channel on the electrocyte to open. Extracellular  positive ions can then flow back into the cell. The side without the nerve connection continues  to pump the positive ions out of the cell.   This gives the left side of the  cell a relatively positive charge,   and the right side a relatively negative charge. Voila, a dipole has been created, and the eel  can start zappin’. The electric charge flows   towards the eel’s head, which is the more  positively charged side of its body, and   is then discharged through the water towards prey. And the more cells that are stacked and lined  up, the more electricity they can generate.   Because incredibly, the eel is able to open all  of its membrane gates at exactly the same time,   creating a huge jolt of electricity. This seems like an extreme ability, but it's  an ability based on what typical muscle and   nerve cells already do. All muscle and  nerve cells have electrical potential   and a simple contraction of a muscle  will release a small amount of voltage.   The cells of an electric eel have  simply amplified that potential. An eel’s ability to make electricity is often  compared to a battery - and this comparison is   no coincidence. The very first battery, invented  in 1800, was inspired by the electric eel. Italian physicist Alessandro Volta observed that  electric eels had stacks of cells that looked   like a roll of coins. He figured if he could  mimic this arrangement, he too, might be able   to generate electricity. He cut coin-shaped disks  from various “dissimilar metals” and stacked them,   trying to find any combination of  them that would create electricity. Eventually, he tried copper and zinc disks,  and separated the stacked pairs with saltwater.   And lo and behold - electricity started  flowing. This came to be known as the   voltaic stack - and is considered to be  the first electric battery ever made. Before this discovery,  scientists barely understood   static electricity. And the electric eel  was only beginning to reveal its mysteries. Scientists soon realized that eels don’t have a   one-zap-fits-all policy. They instead  are able to use different charges for   different things - some for sensing their  environment, some for communicating,   some for stunning their prey, and even some  for controlling the movements of their prey. Electric eels can control  their electricity with finesse. In their dark and murky habitat, electric  eels can’t rely on eyesight for navigation.   In fact, their eyesight is extremely poor. They instead use weak electric discharges,  around 10 volts, to electrolocate.   This weak charge emanates from their body, and  the eel can detect distortions in the electric   field from objects either conducting or  resisting their electricity. This weak   electric discharge is created when the eel simply  activates only a subset of it’s electrocytes. Electric eels can even communicate  using low voltage electric pulses.   By varing the frequency that they produce  these pulses, researchers believe that eels   can convey information about their  sex and reproductive receptivity. And, of course, eels use  their electricity for hunting. Electric eels are mostly nocturnal. They will wait  for darkness, and then sneak up on their prey,   and unleash a series of high  frequency, high voltage pulses.   In this video, the red frames indicate  when the electric organs are discharging.   After just a few milliseconds the  prey is completely immobilized.   Such a high frequency, high voltage attack induces  massive whole-body muscle contractions in the prey   fish. The electric shock causes the prey fish’s  motor neurons, and thus their muscles, to become   simultaneously activated. The higher the voltage,  the more intense the muscle contraction - and at   600 volts or more, these attacks often cause  the the maximum possible muscle contraction,   causing the animal to completely seize  up. This is similar to how a TASER works.   Then, once it is immobilized, the eel can  feast. Electric eels don’t have upper teeth,   so they rely so on suction to pull the prey  into their mouth before swallowing them whole. For a long time, scientists thought that eels  implemented these two types of discharge - low   voltage for navigation and communication; high  voltage for immobilizing prey. But, they soon   learned, there is more to the story. And that eels  use their electricity in even more cunning ways. When looking at the timing of the electric pulses,  researchers noticed an interesting pattern. ‘‘Introduction of prey into the aquarium  arouses the eel, causing it to swim around,   but often stopping in a  particular corner of the aquarium.   During these stops, two high-voltage pulses  with an interval of about 2 ms are emitted.’’ After these two high voltage  pulses, the eel takes a pause,   and then proceeds with its usual  high-voltage, high frequency attack volley. These two high voltage pulses are  known as doublets - and at first,   their purpose wasn’t fully understood.  Why let out two quick pulses initially,   if the massive attack volley will be  more than enough to immobilize prey? Scientists carefully observed the eels’ behavior,   and noticed a few things. 1) a massive attack  volley would almost always come after the doublet;   and 2) the doublets themselves resulted in  a massive whole body twitch in nearby fish. Perhaps the purpose of these  doublets was not to stun the prey,   but to force the prey to  reveal its location to the eel. To test this, scientists  set up a clever experiment.   On one side of an agar barrier they placed an  electric eel. On the other side of the barrier,   they placed a dead fish, and connected  it to a electrical stimulator.   The fish was then sealed in a bag, and  electrically isolated from the eel. The scientists   could electrically jolt the fish with their  stimulator, but the eel could not. The stimulator   was set up so that when the eel emitted a doublet,  it would send a similar shock to the dead fish. When the eels emitted its doublet, and the dead   fish received the simulated doublet -  the eels immediately responded to the   twitch with a high-voltage volley  and strike toward the dead fish. But when the investigators  turned off the stimulator,   and the eel emitted its doublet - no twitch was  produced in the dead fish, and the eel did not   attack. The eel would only attack the fish if  it first twitched in response to its doublet. This study shows that electric eels  can indeed remotely control their prey,   forcing them to reveal their location. The  doublet allows the eel to ask the question:   any fish out there I can eat? The  prey have no choice but to respond. But what if an eel finds itself near an entire  shoal of fish - a shoal that seems particularly   good at keeping its distance to avoid such  shocks? To deal with this, some electric eels   display a remarkable behavior - a behavior  unprecedented in the world of electric fish. Social predation - where groups of  animals coordinate to hunt and kill   prey - is a tactic commonly  seen in mammals like wolves,   orcas, or lions. In fish, this  behavior is almost unheard of. So when scientists travelling through  the Amazon river noticed groups of eels,   sometimes over 100 of them, seemingly  rounding up and attacking prey together,   they almost could not believe their eyes. And  these weren’t just any of the electric eels -   they were volta eels the most powerful of any of  the electric eels, with shocks up to 860 volts. At dawn and dusk, the scientists  noticed an increase in eel activity,   with many individuals leaving the murky  depths and swimming near the surface,   appearing to congregate. These groups of eels  would then swim together towards a shallow hunting   area that contained thousands of small fish. These  groups of sometimes 100s of eels would then start   to swim in circles, herding the fish into prey  balls, and pushing them to shallower water. Then, between 2 to 10 individual eels would  launch a joint predatory strike. In this   video you can recognize the attacking eels by  their synchronized sinusoidal body posture.   The fish hit with the electrical attack  spasm so hard that they jump out of the   water - and then return to the surface stunned and  motionless. The eels then quickly eat the fish. The eels would carry out this  attack sequence five to seven   times, and each time, a different subset of  eels would produce the electrical attack. Although the researchers weren’t able to measure  the voltage of the coordinated electric attacks,   they estimate that 10 Volta’s electric eels  working together could create 8600 volts. This hunting technique allows the eels to subdue   huge quantities of prey that would  normally be too evasive to capture. And it’s not just that these eels  were stuck together in a confined   area, forcing them to feed  on the same groups of fish.   These eels were congregating from far and  wide, to repeatedly forage together over time,   using communication in the form of low  voltage electric pulses and body posturing. It’s unknown if the eels have any  familial relationship to each other,   like is common with many other pack hunters.  But scientists are working to find that out.   Only 9 other species of fish have ever been  observed to hunt together - and the electric   eel’s tactics may be the most formidable. This  shows us that animals we think we understand   can have more than one survival strategy - that in  isolated regions and specific groups of animals,   predator prey interactions may  not be at all what we expect. One lingering question that may have come to your  mind is - how do the eels not shock each other? It’s believed that the electric organ  of an electric eel is padded with   adipose tissue that insulates the  fish from its own electric shock.   But how do they prevent getting  shocked from other eels? The likely answer is, that they don’t. Electric eels are probably pretty huge for exactly  this reason. They are much larger than their   prey - such that an eel’s current will easily  incapacitate their target, but won’t do much to   their larger bodies, similarly to how a single  electric eel shock to us would hurt for a sec,   but not kill us. To an eel, getting shocked  is likely just part of doing business. An eel’s entire world revolves around its  electricity. And largely thanks to the electric   eel, so does ours. Next time you charge your phone  or stick some double As in your remote, you can   thank the electric eel for its contribution to our  understanding of electricity. And we continue to   be inspired by them. Researchers are currently  working on an entirely new type of battery   inspired by eels - a soft and flexible battery  that can power medical implants and soft robots.   We are likely just beginning to  understand these incredible creatures,   with many more of their mysteries still  lurking in the muddy waters of the Amazon. Understanding the electric eel has ignited  a curiosity in me about the electricity   in the world all around us. Its nearly  impossible to NOT take it for granted.   I know I certainly don’t often think  about how the lights in my kitchen work,   how my computer stays charged, or how the  grid in Texas is teetering on a knife edge   and is doomed to fail at any moment - ok maybe  I do think about that last one. But in general,   how electricity works is rarely on my mind. But  the more I learn, the more incredible it becomes. With Brilliant’s Electricity and Magnetism  course, you can discover the physical laws of   electricity and magnetism that are the backbone of  our modern world. It begins with simple analogies,   and walks you through step by step how electricity  was discovered, and slowly building to explain   some fundamental equations that look complicated,  but make total sense when every step is broken   down for you. It’s not overwhelming like college  classes can be, and rather than penalize you when   you get an answer wrong, it guides you to the  right one with a more in depth explanation. There are so many courses to dive into,   from neural networks to algorithms,  to the physics of every day. To get started for free, visit to  brilliant.org/realscience or click on the link in   the description, and the first 200 people will get  20% off Brilliant's annual premium subscription. And if you’re looking for  something else to watch right now,   you can watch our previous video about the  mysteries of deep sea gigantism - or watch   Real Engineering’s latest video  about self healing space suits.
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Channel: Real Science
Views: 717,488
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Length: 18min 27sec (1107 seconds)
Published: Sat Jul 30 2022
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