Why We Can't Truly Explore Where Sperm Whales Go

We have satellites that can track a single tagged shark across the entire Pacific Ocean. We have drones that can follow a blue whale for weeks. But if you want to see what a sperm whale actually does all day, you can't. You literally cannot follow it. The second this animal takes a breath and dives, it vanishes. It takes the exact same air we breathe and carries it into a world so unbelievably hostile that if our most advanced military submarines tried to chase it, they would instantly implode we are sharing the planet with a mammal that spends its entire life commuting to an alien world so where exactly are they going and why is it physically impossible for us to just follow them hey guys you're watching let's go swimming a channel made by real people for real people join me as we explore the invisible vertical world where sperm whales spend their lives completely out of reach. Most mammals in the ocean operate on a horizontal plane. A great white shark or a tuna will swim hundreds of miles across the ocean, but they generally stay within the upper layers of the water. They move left, they move right, they go forward. Sperm whales don't do that. Their entire existence is based on going straight down. When a sperm whale dives, they're commuting to an entirely different world. They routinely plunge thousands of meters straight down, passing completely through the epipelagic zone, tearing through the twilight zone, and dropping directly into the bathypelagic and abyssopelagic zones. And this is a massive commitment. They'll stay down there for up to 90 minutes at a time on a single breath of air. Imagine taking a deep breath, jumping onto an elevator and riding it down past the height of the Empire State Building, then past the height of the Burj Khalifa, and then just keeping going into absolute darkness, all before you need to exhale. They spend the vast majority of their time in a place where we simply cannot follow them. Which begs the question, with all our modern technology, why don't we just chase them down? we have submarines we have deep-sea submersibles we send robots to the bottom of the Mariana Trench if a whale swims down we should just be able to get in a submersible and tail it right well no because human deep-sea technology is incredibly slow and frankly completely useless for a high-speed chase when humans go to the deep ocean we use submersibles that are essentially just just heavy metal elevators. They drop down very slowly to conserve battery, and once they're at the bottom, they maneuver using these tiny thrusters. A standard research submersible might max out at a top speed of 2 or 3 miles per hour. A sperm whale can usually cruise at much faster speeds than that, and when they actually want to move, they can hit bursts of over 20 miles per hour. If you tried to follow a sperm whale in a submarine, you'd be maxing out your thrusters just to watch it effortlessly vanish into the dark the whale can descend rapidly change directions in an absolute instant and completely outpace our most advanced deep sea vehicles with just a few flicks of its tail submersibles also have strictly limited battery supplies and life support systems we can only stay down for a few hours before we absolutely have to begin the agonizing ascent back to the surface the whale just does this all day every day without even thinking about it but speed isn't even the main reason we can't follow them the real issue is what happens to your body when you go that deep but even if we somehow manage to build a nuclear-powered submersible that could actually keep up with a diving sperm whale we immediately run into an even worse problem the pressure once you pass 1,000 meters deep and enter the midnight zone the physical weight of the ocean becomes genuinely terrifying. Water is incredibly heavy. For every 10 meters you go down, the pressure increases by one atmosphere. By the time a sperm whale reaches its hunting grounds, the pressure is over 100 times greater than it is at the surface. This is enough pressure to instantly crush basically anything we've ever built. To even survive down there, human submersibles have to be built out of extremely thick spheres of titanium. We basically have to build our vehicles to look like this, just to fight off the weight of the water. And because we have to build them this way, our windows have to be heavily reinforced, which completely ruins our field of vision. We're fighting a constant war against physics just to keep a human alive for a few hours in the deep ocean. So if the ocean can effortlessly crush military-grade titanium, how does a squishy animal survive it? Well, humans try to survive the deep by fighting the pressure. We build rigid boxes full of air the sperm whale survives by doing the exact opposite it just yields to it the biggest danger of deep sea pressure is what it does to air air is compressible if you take a balloon down to the abyss it shrinks into almost nothing if you take a human lung down there it collapses your ribs snap and the nitrogen in your blood becomes incredibly toxic but sperm whales have a completely different strategy when they dive they don't hold a massive amount of air in their lungs in fact their rib cages look like this they're actually hinged so that they can fold inward allowing their lungs to completely collapse on purpose they actually store their oxygen directly in their blood and their muscles they have massive concentrations of a protein called myoglobin which binds to oxygen and holds it inside the muscle tissue itself their bodies are essentially mostly incompressible liquids and dense solids since there are no giant pockets of air left in their body to be crushed the pressure of the deep ocean doesn't actually bother them they don't fight the ocean they just let the ocean compress them and their bodies are perfectly designed to handle it but surviving the pressure is only half the battle because once you get down there you still have to actually see okay so the whale can survive the pressure effortlessly but let's say we completely ignore the pressure problem let's pretend we have an indestructible submarine that can easily follow the whale down to 2,000 meters we still wouldn't be able to see a single thing they're doing humans are visual creatures we rely almost entirely on our eyes to understand the world around us but past 1 000 meters deep absolutely zero sunlight penetrates the water it's just dark to explore this human submersibles have to strap stadium level flood lights to their hulls we turn them on and we illuminate a tiny little cone of water in front of us. But the moment you turn on a massive floodlight in the deep ocean, you completely destroy the natural environment. The animals that live in the abyss have evolved for millions of years in total darkness. Many of them have oversized eyes designed to pick up the faintest traces of bioluminescence. If you blast them with a 10,000 lumen LED array, you permanently blind them. You scare off all the prey. You completely alter the behavior of every single animal in the vicinity. If we try to light up the sperm whale's hunting ground to see what they're doing, we instantly ruin the hunt. We cannot visually observe this environment without actively destroying the reality of it. So if eyes are completely useless down here, how is the whale actually hunting? They just use their heads. A sperm whale's head makes up about a third of its entire body length, and it looks like, well, this. It's basically just a giant rectangle. For a long time, people had no idea why their heads were shaped so weirdly. But it turns out that massive block of flesh is actually the most advanced sonar system on the planet. Inside their heads is a massive cavity filled with a waxy liquid called spermaceti. When the whale wants to see, it forces air through a pair of lips near its blowhole, creating a clicking sound. This sound bounces off the front of their skull, travels forward through the giant barrel of spermaceti oil, and is focused into a highly directional acoustic beam. They're projecting a highly concentrated blast of acoustic energy straight into the dark. When these sound waves hit an object, like a giant squid, they bounce back. The whale receives these echoes through its lower jaw, which conducts the sound directly to its inner ear. This echolocation is so precise that a sperm whale doesn't just know where an object is. They can tell exactly how big it is, how fast it's moving, and even what its internal organs look like. They're navigating and hunting in a completely different sensory dimension than we are. But this echolocation isn't just a harmless trick. It's an actual weapon. And I know echolocation sounds like a neat little trick, similar to how bats find moths in the dark. But sperm whale sonar is actually genuinely dangerous to be around. Sound travels about four and a half times faster in water than it does in air. And water is incredibly dense, which means acoustic energy hits much, much harder. Sperm whale sonar clicks are the loudest biological sounds ever recorded on Earth. And if you're watching this on the Let's Go Swimming channel right now, please don't turn your volume all the way up, because these clicks can reach up to 230 decibels. For context, a jet engine at takeoff is about 150 decibel. A sound at 230 decibels in the water is so powerful that it doesn't just hurt your ears. It actually impacts your physical body. If a human diver is in the water right next to a sperm whale when it fires off its loudest clicks, the experience is horrifying. Divers who have been pinged by sperm whales report feeling the sound physically heating up their bodies. The acoustic waves literally vibrate the water molecules inside human tissue. If you get hit by a full power click at close range, the sound waves can vibrate your internal organs so violently that you're probably going to die. This animal is projecting sheer concussive force into the water, and it proves, once again, that human bodies are completely out of their depth, anywhere near a hunting sperm whale. So if we can't physically be in the water with them, how do we even know what they're doing down there? We actually do have ways of knowing where these whales go. Researchers routinely attach acoustic tags and hydrophones to the backs of sperm whales when they're resting at the surface. These tags record depth, acceleration, and audio. When the whales come back up, the tag pops off, floats to the surface, and scientists download the data. So we know exactly how deep they dive. We know exactly how fast they swim. We can listen to the audio recordings of their clicks and echoes. But staring at a line graph on a computer screen completely ruins the magic of what's actually happening. We can track a dot on a grid, but we have absolutely zero visual context for what that dot is actually experiencing we can hear the clicks speeding up as the whale chases something but we can't see the environment they're moving through we can't see the prey dodging and we can't see the actual fight we get the raw data of the hunt but the actual reality of the deep ocean remains completely hidden and that's a shame because what they're actually hunting is genuinely terrifying they're going down there because that's where the largest invertebrates on the planet live sperm whales are the apex predators of the deep and their primary targets are giant squids and colossal squids these are creatures that can grow over 40 feet long and weigh hundreds sometimes over a thousand pounds because the ocean is so empty a sperm whale has to eat roughly a ton of food every single day just to survive they cannot survive by eating tiny shrimp or small fish they need massive meals and the only place to find those meals is thousands of meters below the surface this creates one of the most insane predator prey dynamics on earth every single day massive whales plunge into the abyss to wage war against sea monsters and the craziest part is that these massive deep water brawls happen thousands of times a day all over the world and no human has ever actually seen it happen but we know for an absolute fact that these battles happen because the whales literally wear the evidence when sperm whales are studied, or when they occasionally wash up on beaches, their massive heads look like this. They're covered in these perfectly circular scars wrecked across their skin. These are the exact dimensions of the suction cups from giant and colossal squids. And if the scars on the outside weren't enough proof, we also have the evidence from the inside. A squid's body is mostly soft tissue, which the whale easily digests. But a squid's mouth has a razor-sharp beak that looks like this. It's made of chitin, which means the whale literally cannot digest it. When scientists look inside the stomachs of deceased sperm whales, they routinely find thousands of these giant squid beaks just sitting there. Sometimes, the whale's digestive system coats these irritating beaks in a waxy substance to protect its stomach lining, which eventually gets passed out into the ocean as ambergris, a highly valuable substance used in perfumes. So we have the battle scars, and we have the undigested weapons of their prey. The physical proof of the hunt is undeniable, which naturally leads scientists to try the next most obvious solution to see it happen. Why not just stick a camera on a whale? We do this with great white sharks and sea turtles all the time. You suction cup a pressure-proof camera to the animal's back, and you just let it record. But when researchers actually do this to a sperm whale, the results are incredibly disappointing. Remember the light problem? The camera can't have a massive floodlight on it, or it will ruin the hunt. So the camera is essentially just recording in the dark. If you watch the footage from a sperm whale camera tag, it's mostly just hours of nothing. Occasionally, you might see a blurry flash of bioluminescence as the whale disturbs some deep-sea plankton. You might hear the audio of the whale clicking rapidly. You'll see the camera shaking violently as the whale twists and turns. And then, because they're swimming so fast and literally wrestling sea monsters, the camera almost always just gets ripped off and floats away. Even when we successfully hitch a ride on the predator, the sheer darkness and chaos of the environment render our visual technology completely useless. But just because we can't see the fight, doesn't mean that we don't know exactly how it goes down. Based on the acoustic data we've recovered, we actually know exactly how this hunt plays out. It's just a high-speed dogfight. The whale descends into the abyss, firing off rhythmic clicks. Click, click, click. It's scanning the void. Suddenly, the sound waves bounce off the soft tissue of a giant squid hanging in a water column. The whale instantly turns and dives. As it gets closer, the whale increases the speed of its clicks to get a higher-resolution acoustic image of the target. The clicks get faster and faster, turning into a rapid-fire sound called a creak or a terminal buzz. The squid, despite not having great hearing, can sense the pressure waves in the water. It knows something massive is coming. The squid fires its siphon, blasting a jet of water to rocket itself backward into the darkness. But the whale is locked on. It twists its massive body, snapping its jaws in the dark, trying to catch the squid before it can disappear into the abyss. It's a violent chase, governed entirely by sound and water pressure. But obviously, hunting a 40-foot squid isn't exactly a guaranteed victory. Sperm whales have the size of a sonar, but these squids are heavily armed. Giant squids have arms lined with serrated suckers, and colossal squids take it a step further. Their tentacles literally look like this. They're lined with razor-sharp hooks. When the whale finally manages to bite down on the squid, the squid fights back with everything it has. It wraps its tentacles around the whale's head, digging those hooks deep into the whale's skin. It uses its parrot-like beak to tear at the whale's flesh, and the squid has one major environmental advantage – time. The whale is holding its breath. Every sudden movement, every twist, every bite burns precious oxygen. If the squid can fight hard enough or wrap itself awkwardly around the whale's jaw, it can stall the fight. If the whale spends too much time wrestling in the dark, it risks running out of oxygen. Sometimes the whale realizes it's burning too much energy, gives up, and has to race back to the surface. The squids do escape. It's an incredibly dangerous arena, and the whales are risking their lives every single time they dive. But this ultra-violent hunting strategy completely overshadows the weirdest thing about these animals. Because, when they aren't hunting, they're actually incredibly social animals. Female sperm whales live in these massive pods with their families, and they stay together for their entire lives. raise their calves together they protect each other and they communicate constantly and because they live in an ocean where visual communication is useless their entire society is built on sound sperm whales use specific patterns of clicks called codas to talk to each other and scientists have discovered that these codas aren't just random noises different groups of sperm whales have entirely different regional dialects a pod of sperm whales in the Pacific Ocean uses completely different click patterns than a pod in the Atlantic. They have distinct clans, and they pass these specific dialects down from generation to generation. They can communicate across vast distances, using deep ocean channels to send acoustic messages to other pods miles away, and it goes way deeper than accents. In 2024, a team of researchers went through 8,719 recorded codas from about 60 sperm whales in the Caribbean, recordings that stretched all the way back to 2005, and they found that the whales weren't just repeating a fixed set of patterns. They were changing the rhythm. They were changing the tempo. They were stretching or squeezing a coda to match the whale they were talking to. And every now and then, they tacked one extra click onto the end. Mix all of those pieces together, and you get far more possible signals than anybody thought these animals had. The researchers compared it to a kind of phonetic alphabet, which sounds like we're about to crack the code. Except, nobody has any idea what a single one of these coders actually means. They're talking, we're recording all of it, and we can't read a word. We're completely missing out on an entire acoustic culture, a complex social network that exists entirely in the darkness of the abyss. And because they're so social, they do some genuinely bizarre things when they think nobody is watching. Start with the most obvious problem in this entire lifestyle. If your whole job is at the bottom of the ocean, what do you do with the baby? A young calf can't just tag along with its mother on a full hunting dive. So while mom is off working in the dark, the calf is stuck at the top. And a baby whale bobbing around alone at the surface is basically a free lunch for a passing pod of orcas. So the whales babysit. Researchers who followed these family groups noticed that the adults don't all dive at the same time. They stagger their dives, so that when one whale heads down, another one is still up there. and the calf always has somebody right next to it and it isn't only the mother doing the work the calf gets passed around between the other members of the group it's a daycare a daycare run by the largest toothed predators on earth on a rotating shift schedule mom gets to go eat the kid doesn't get eaten and everybody takes a turn and when something does show up to attack the whole family responds they pack into a tight circle with their heads in the middle and their tails pointing outwards, like the petals of a flower, with the younger whale protected by the group. Scientists call it a rosette. In March of 2024, people on a boat off the coast of Western Australia watched a pod of orcas go after a group of sperm whales doing exactly this. And then the sperm whales pulled out the backup plan. They pooped. All of them. Then they swished it around with their tails until the water turned into one giant reddish cloud. It's reddish because of all of the squid they eat, by the way. And it worked. The orcas backed off and left. An animal with a whole spoken culture saved its own life with a diarrhoea smokescreen. And their social life gets even weirder than that. In 2011, two researchers off the Azores found a group of sperm whales, calves and all, hanging out with an adult bottlenose dolphin. The dolphin had a curved, S-shaped spine. And over the next eight days, they kept finding it with the same whales, nuzzling them and rubbing up against them. And the whales just let it. The researchers suspected the dolphin's spying made it hard to keep up or fit in with its own kind, so it went and found a new crowd. Nobody had ever recorded sperm whales bonding with another species like that. But notice where every single one of those stories happened, at the surface. The one thin slice of their world where a human can actually be in the room. And because they have this complex social structure, they also have some incredibly weird communal behaviors. Behaviors that we only ever find out about through pure, dumb luck. A few years ago, a group of researchers and photographers were drifting in the open ocean when they stumbled across something completely bizarre. Below the surface, an entire pod of sperm whales was completely motionless, suspended perfectly vertically in the water column. Their noses were pointing straight up toward the surface, and they were completely silent. They were sleeping. Sperm whales, like a lot of marine mammals, actually shut down half of their brain at a time so they don't drown. But no one had ever seen them sleep like this, hanging in the water like giant monoliths. This was literally only discovered because a boat just happened to drift into the exact right spot at the exact right time. If one of their most basic daily behaviors was only caught by pure accident, it proves that there are likely countless other behaviors, rituals, and habits that we have never seen and probably never will see. Because trying to study them creates a massive scientific paradox. And the best example of that paradox isn't even the whale. It's the whale's lunch. Think about the giant squid for a second. Dead ones have been washing up on beaches and floating at the surface for centuries. We've pulled their beaks out of whale stomachs by the thousands. And yet, For almost all of human history, nobody had ever seen a living one down where it actually lives. The first photos of a live giant squid in its natural habitat didn't come until September of 2004. A Japanese team spent three years trying, lowering a baited line with a camera attached, and at 900 meters down, a squid finally grabbed it. It got snagged on the hook, fought for more than four hours, and eventually tore off its own tentacle to get away. set of photos isn't video and a scientist named Edith Widder had a theory about why nobody could get any maybe we weren't failing to find the squid maybe the squid was finding us first and leaving so in 2012 off the coast of Japan her team did everything backwards they took a camera system called the Medusa hung it from a buoy about 2,300 feet down and just left it there for hours no No engine, no pilot. And instead of white floodlights, it used red light, which most deep-sea animals can't see. And for the bait, it had a fake electronic jellyfish. It copied the glowing display a real jellyfish uses as a defense, which to a big predator can mean there's a meal nearby. And it worked. A giant squid came out of the dark to check the lure, and for the first time ever, we had video of one alive in its own home. In 2019, the same camera system did it again in the Gulf of Mexico, at 759 meters. That squid was at least 10 feet long. It came in for the fake jellyfish, realized it wasn't food, and vanished. And the colossal squid took even longer. Nobody filmed a live one in its natural habitat until March of 2025, a full hundred years after the species was first named, from pieces found in the stomach of a sperm whale. And the one they filmed was a baby, about a foot long. So why not just hang a quiet camera down there and wait for a whale to show up? Because that camera sits in one spot looking at a tiny patch of water in an ocean that covers most of the planet. You'd need a whale to catch a squid directly in front of the lens. You'd have better odds of leaving a doorbell camera in the middle of the Serengeti and hoping to film one specific lion. So look at the scoreboard. Two species of sea monster and a tiny handful of sightings on camera. one of them is a squid on its own, in the dark, minding its business. Not one of them has a whale in it. And we only got to see the giant squid at all once we stopped lighting up the water, stopped making noise, and basically stopped being there. And that, right there, is the core problem with trying to explore the deep ocean. In physics, there's a concept called the observer effect, which basically just means that the second you try to watch something happen, you change the where it happens. Nowhere on Earth is this more true than in the Bathypelagic Zone. The moment humans enter their world, we ruin it. We bring grinding mechanical thrusters that drown out their acoustic communication. We bring blinding floodlights that permanently damage the eyesight of the deep-sea ecosystem. We bring clunky metal boxes that disturb the water pressure and scare away the prey. We can never observe a sperm whale acting completely naturally in the deep ocean because just by being there, we ruin it. The environment only functions the way it does when it's completely dark completely silent and completely untouched by human engineering the very tools we need to explore their world are the exact same tools that destroy the reality of it leaving us with one uncomfortable truth humans are incredibly used to conquering every single environment on this planet if a mountain is too high we climb it if a jungle is too dense we clear it we're used to the idea that with enough money and enough technology we can go anywhere and see anything but the sperm whale's domain is the one place we're permanently locked out of it's an environment so extreme so heavy and so dark that we simply cannot exist there without completely ruining it we can track their data we can listen to their clicks and we can find the scars on their skin but the actual experience of the deep ocean the high speed hunts the acoustic culture the reality of the abyss belongs exclusively to the animals that were built for it and no matter how advanced our submarines get the sperm whale will always be the ultimate gatekeeper of a world we can never truly see but anyways thank you guys for watching and i hope you enjoyed this one if you have any suggestions for what ocean topic you want to see next let me know in the comments because i do actually read them and if And if you want to see another video like this, check this one out here.