Astrum Space - The Giant Creatures Lurking Deep in the Ocean | Astrum Earth

Episode Date: June 24, 2026

Earth’s deepest oceans are full of real-life monsters: colossal squids, crabs the size of cars, and sharks with catapulting jaws. In this video, we’re exploring the giants of the deep sea. Find out what scientists have discovered, and why the most extreme depths breed the ocean's biggest creatures.▀▀▀▀▀▀🔒Remove your personal information from the web at https://joindeleteme.com/ASTRUMEARTH and use code ASTRUMEARTH for 20% off DeleteMe international Plans.▀▀▀▀▀▀Astrum's newsletter has launched! Want to know what's happening in space? Sign up here: ⁠https://astrumspace.kit.com⁠A huge thanks to our Patreons who help make these videos possible. Sign-up here: ⁠https://bit.ly/4aiJZNF

The most hostile place on the planet doesn't destroy life, but grows it into giants. Right now, in total darkness, six kilometres below the surface of the ocean, there's a jellyfish trailing tentacles the length of a London bus, and it's not alone. There are squids with eyes the size of basketballs, crabs the size of cars, a six-meter shark that catapults its entire jaw clean out of its face. And that's not to mention one of the largest active predators on the planet that can grow up to 500 kilograms in just two years. This might sound like the stuff of nightmares,

and in many ways, the bottom of the ocean is. Down past the midnight zone, amongst near freezing temperatures and crushing pressures, resources are scarce. Less than 1% of the food from the surface ever makes it down to the ocean floor. There simply shouldn't be enough energy to build something big. And yet there is, and not just big, gigantic. So why do the deepest, darkest, most hostile parts of our ocean

produce the largest creatures on Earth? This mystery has baffled scientists for more than a century. But in 2025, that all changed, and we finally found the answers we were looking for. I'm James Stewart, and you're watching. Astrum Earth. Join me as we descend into the darkness to reveal monsters of the deep and the astonishing science of their abyssal gigantism, each one more enormous than the last. We'll find out not just why they exist, but how secrets written into their DNA might even affect you.

Deep Sea giants may sound like this stuff of fiction and in many cases they are. The Hydra, the Cracken, the Leviathan. But as with many myths and legend, they're also rooted in truth. Now, finding these deep sea giants has never really been the problem. The history books are packed with tales of these beasts, their bodies washed up dead and degraded on beaches. But without seeing them alive and well in their natural habitats, we never truly understood how they grew so large, until now.

In 2025, we finally filled in those huge gaps in our scientific knowledge. ROVs probe deeper in some places than ever before. 4K cameras captured these creatures alive for the first time. And genomic sequencing of their DNA revealed something mind-blowing. As soon as you enter the ocean and go down past 200 metres, sunlight fades. Past 1,000 metres, it's gone entirely. Welcome to the Midnight Zone. The home of a creature that looks like it's crawled in from a,

galaxy far, far away. Its species name is Vadery, because when the scientists who first described it in January 2025 saw its helmet-shaped heads, they thought of one person, Darth Vader. This Sith Lord is actually a super-giant isopods, or if you prefer the nightmare version, a wood louse the size of a soccer ball. Pick one up, and people have when they've caught them in nets, and you're holding 33 centimetres and nearly a kilogram of armour-plated deep-sea tank. Flip it over and there are 14 legs. Two compound eyes built from roughly 4,000 lenders each, pat's like honeycomb,

and a mouth made of four jagged plates that close inward. Giant isopods can live as deep as the Barthiel zone, the deep continental slope, somewhere around 2,000 metres down, pitch black, near freezing, crushing pressure and almost nothing to eat. So how do they survive? When a dead whale carcass or dead tuna does drift down, these isopods gorge themselves so heavily that they can't move afterwards. Scientists politely call it post-feeding immobility,

although you and I might just call it a food coma. This can keep Barthenamus Vedery full for an incredibly long time. In fact, one individual in a Japanese aquarium went five years and 43 days without eating. Not because it was sick, it just wasn't hungry. But here's the paradox. In a world with almost no food, you'd expect tiny, hyper-efficient scavengers, right? As a basic principle of evolutionary biology, when food is scarce, being small is an advantage. Smaller bodies need less energy to survive.

But in the deep ocean, you get an armored giant. that treats half a decade without a meal as a minor inconvenience. Down here, being big isn't excess. It's strategy. The deep ocean is cold. Below 1,000 metres, temperatures hover between 2 and 4 degrees Celsius, just above freezing. Now, Barthenamus Vaderie is cold-blooded, and you would therefore be forgiven for assuming that it doesn't generate its own heat,

but it does. Even cold-blooded animals lose energy to their environment. Chemical reactions in cells produce heat as a byproduct. And in cold water, a larger body retains that energy more efficiently. They might not have warm blood, but they don't want to freeze. This idea that a larger body stores more energy and burns it more slowly is called Bergman's rule, and it dates back to 1847, when German biologist Carl Bergman noticed something simple. Animals in colder places are bigger.

It's about the ratio of surface area to volume. Let's break this down for a second. So a cube with size of one centimetre has six centimetres squared of surface area and one centimetre cubed of volume. Make it two centimetres on each side. The volume goes up eight times, but the surface area only goes up four times. The bigger you get, the more inside you have relative to your outside. Bartholomus's giant body holds more energy than a small one, but crucially, it burns through that energy far more slowly.

Less surface area relative to its mass means less heat escapes, which means its metabolism can drop to almost nothing and stay there. It's not waiting for food. It's barely noticing food is gone. This explains why this creature has grown so large on such little food. But a big question still remains about how they evolved to be like this. And it turns out the answer lies even deeper into the ocean with an even bigger monster, so extreme that when scientists sequenced its DNA, they had to check the results twice. You'll know already about the Mariana Trench. In fact, we made a video on it.

In this place, seven kilometers under the ocean's surface, so dark and crushing we barely visited it, scientists found a super giant. Ali-Chella gigante is the world's largest amphipod at 34 centimetres long. Now, that might not sound enormous until you realise its shallow water equivalent is the size of a grain of rice. This deep sea beast is actually 50 times the size of its cousins. It's the equivalent of a can of beer scaled up for the size of a T-Rex. Alley-Cella is built to live in what's called the Aphotic Zone, below 1,000 metres where less than one percent of sunlight makes it through.

Most deep sea amphipods here are red or orange, and there's a really good reason for that. Camouflage. Red light has a longer wavelength compared to other colours, and is usually absorbed within the first hundred metres or so of the ocean. So essentially no red light makes it to the aphotic zone. Here, red animals appear completely black, the perfect disguise. But Ali Chella isn't red. It's almost a translucent white.

Why? Well, down here it has virtually no predators. It's too big and it's armoured exterior too tough to make it a worthwhile meal for other inhabitants of the deep. The fact that it's not camouflage also suggests that visual hunting isn't a big thing at this depth. In other words, it doesn't need to hide. Now, as interesting as all of that was, it doesn't tell us how this thing became a giant. This was something scientists only discovered in 2019, when they sequenced in. its genome. Every living thing runs on a genome. It's like a master instruction manual. Humans, mice, dogs, virtually all creatures have roughly the same number of genes, somewhere around 20,000. When researchers measure the nuclear genome sizes of 13 deep-sea amphipods,

Ali Chellas dwarfed everything else in the study by a factor of nearly nine. At 34-gigabases, it is one of the largest crustacean genomes ever recorded. And crucial, in this case, the animals with the biggest genomes had the biggest bodies. Size is written into the blueprint before the animal even begins to grow. Then in 2021, researcher Wen Hao Li and his team at Shanghai Ocean University went deeper. They compared the transcriptomes of Ali Cheller against a much smaller Hidal relative and found something striking. If you needed a quick refresh on transcriptomes, by the way, here's how I think

of them. So the genome in my head is sort of a library of every book ever written, and the transcriptomes are the sort of list of books currently open on the reading desk. Essentially, the transcriptome tells us which instructions the body is actually using at that exact moment. Now, Ali Chella carries genes that regulate how cells multiply and how bodies accumulate mass, that show clear signs of positive selection. Genes that are not just present, but actively being pushed by evolution. The signal, it seems, never fully stops. Most animals reach adult size and the instruction to grow goes quiet. In Alicela, something keeps the dial turned up, year after year, decade after decade with no hard ceiling. Scientists call this indeterminate growth, and Alichella's

genome appears built for exactly that. This is the molecular machinery that allows gigantism to happen. At the surface, a giant genome would be a liability. It's slow and inefficient to copy and uses up lots of energy. You'd lose to faster, leaner competitors. But 7,000 meters down, where life moves slowly and predators are scarce, that massive genome is now an advantage. So food scarcity and sub-zero temperatures make it pay for creatures to be big.

And a huge genome that never gets the signal to stop growing is how deep sea giants grow so huge. So that's it, I guess. End of video, thanks for watching and we'll see you in the next one. If only things were that simple. Because our next giant takes things even further. And to find it, we have to go somewhere that shouldn't support life at all. To meet an animal so strange, it forced sciences to rethink what an animal even is. Most starfish have five arms, but as you descend 500 metres down, something strange happens.

They suddenly get 50. This is the Antarctic Sun Starfish, 60 centimetres across, living in water so cold that it sits a fraction of a degree above freezing. It uses those arms like fishing rods, writhing through the water, snatching anything that drifts past, which is why it's often referred to as the wolftrap starfish. But before we get into why this starfish is so supersized, a quick word on how deeply strange starfish already are. They have no brain and no bloods, and to eat, they eject their stomachs out of their mouth to engulf the food, digest it and then slide it back inside. It's both awesome and disgusting in equal measure.

But anyway, in 2023, Stanford researchers were mapping the master genes that tell every animal cell what part of the body it belongs to, whether that's a tail, a lung, a fin, or something else. But when they got round to the starfish, their results were astonishing. Because the starfish is just a head. A head that at some point evolved the ability to walk around on the sea floor, eating things by ejecting its own stomach. And if you thought that was cool, by the way, it's not until you zoom into the cellular level that the magic really begins. You see, there are two ways to build a bigger animal.

One is to pack in more cells, which is what elephants do. An elephant cell is roughly the same size as a mouse cell. there are just trillions more of them. Or another option would be to make each individual cell bigger. Inside every living cell, two processes are constantly racing. The cell building itself up, making proteins, accumulating mass, and the cell copying its DNA, then dividing it into two, which keeps it nice and small.

In warm water, these two processes run at roughly the same speed, copy, divide, copy, divide. But here's the thing. In near freezing water, the chemistry, of cell growth changes. Protein synthesis, the building part, keeps going, but the signal to divide, slows down. The cell keeps accumulating mass,

but the trigger to split is delayed. By the time the vision finally happens, the cell is already far larger than it would be in warm water. And if every brick in the wall is oversized, the wall is oversized too. The Antarctic Sun Starfish lives in water that sits a fraction of a degree above freezing all year round, exactly the conditions where this mechanism runs at full power.

50 arms, 60 centimeters across. The coal didn't just allow this animal to grow. It built it from the inside out. Now, don't get me wrong, these animals are pretty cool, quite literally in the case of the starfish, but we promise you deep sea giants, the really big stuff. And I am ready to deliver. From here on out, these things are going to get bigger and bigger and bigger.

Let's start with a creature with, Legs nearly four metres long, with the same basic body plant as every insect that ever lived. Made absolutely massive by an invisible ingredient, almost everything on Earth needs to survive. Every arthropod, that's every insect, spider and crab, shares the same design floor. No veins. Their blood doesn't travel through a closed system, but instead sloshes around loose inside the body cavity, bathing the organs directly. Scientists, perhaps rather kindly,

call it an open circulatory system, but really it's a terrible way to deliver oxygen at scale. On land, this puts a hard limit on size. The largest insect alive today, New Zealand's giant wetter cricket, weighs barely more than a golf ball. But 300 million years ago, atmospheric oxygen was nearly double what it is today,

allowing creatures to grow much larger. Dragonflies had wingspans of 70 centimetres with the same body plan as a regular dragonfly, just supercharged by oxygen. Back to today off the coast of Japan, cold water sweeps down from the north in powerful deep currents. At 10 degrees Celsius, this seawater dissolves roughly 40% more oxygen than warm surface water. And that oxygen-rich current has been flowing over the same stretch of seafloor for millions of water. of years, long enough for evolution to take advantage. A few hundred meters down, we find the Japanese spider crab, locally known as Takarashi Gani, meaning tall legs crab, with legs stretching to almost four meters tip to tip, wider than

a VW beetle. Weighing up to 19 kilograms, this is the largest living arthropod on Earth. That same open circulatory system that stops insects growing large on land is now a crucial advantage. Cold water doesn't just carry more dissolved oxygen. It dramatically slows the metabolic rate of every cell in the animal's body, reducing how much oxygen it actually needs. The demand drops, and larger bodies in cold water are better at regulating oxygen uptake

than smaller ones. As a crab grows, its body volume increases fast. than the surface area of its gills. In warm water, that creates a problem. There's not enough gills surface to supply enough oxygen to all of that tissue, but cold water changes the equation in two ways. Firstly, it slows down the metabolism of every cell,

meaning the body needs less oxygen to keep running. Secondly, it holds more dissolved oxygen per litre, so the demand drops and the supply rises simultaneously. A body size that would slowly suffocate in the tropics, freeze comfortably in cold water. Like most long-lived decapore crustaceans, there is no final instruction to stop growing. The legs keep lengthening year after year for as long as the animal survives. With a lifespan that can reach 100 years, that's a lot of leg.

So if their legs never stop growing, why don't we find crabs with 10, 20, 100 meter long legs? Well, there's still a hard limit on the total energy available, and although they keep growing, happens very slowly. In most cases they die before the growth stops. Every year the Japanese spider crab mults its shell and grows a new one, spending days as a completely defenceless, soft-bodied, four-meter target. And often that spells the end of the road for this crab. But some other giants do far better. Before we go on, there's actually one other giant problem I need to get off my chest. Data brokers. Those annoying people that are more than happy to sell my personal info to the highest bidder. Things like my email address, home address and even family information.

I mean, why can't they disappear to the bottom of the ocean and join these guys? The good news is this year I've been fighting back because I'm using Delete Me. It removes my personal information from those websites and honestly it's been a total game changer. When I first started using it at the start of the year, I have more data breaches than a spider crab's leg, which put my data at significant risk. Luckily, thanks to delete me, I now have zero. Even when the odd spam email does slip through the net, all I have to do is simply make a request via the online portal, they look into it and sort it out really quickly, and it's very satisfying to shut down the spammers, I must admit. So, if you like to disappear beneath your own digital

deep sea void, why not join Delete Me? There's no deep sea giants like MIR, but they are giving our viewers an awesome deal. 20% off with my link, join delete me.com slash astrum earth and use code Astrum Earth at checkout. Thanks to Delete Me for sponsoring this video. The link is in the description if you want your digital life a bit more private, as we head back to the Giants of the Deep. Dropping down to 1,000 meters deep into the twilight zone of the Pacific Ocean, lives a giant that has remembered. essentially unchanged for millions of years. Yet we only identified one out in the wild for the first time in 2026, the Goblin Shark.

It has a flabby body, a soft and barely calcified skeleton, weak muscles and poor eyesight. In any reef documentary, this thing would be lunch before the opening credits are even finished. And yet, here it is, six metres long, 200 kilograms, with a lineage stretching back a 125 million years into the Cretaceous period. This species has survived mass extinctions, ice ages, and the collapse of entire ecosystems. So either the deep sea is extraordinarily forgiving, or this shark plays a completely different game. It doesn't chase, it doesn't cruise. Instead, it hangs suspended in the darkness, virtually motionless, waiting for a signal.

Every living animal produces a faint electrical field, when its muscles fire, a heartbeat, a twitch, anything. And the goblin shark reads those signals through a snout packed with hundreds of electro receptors. It doesn't need eyes down here. It sees in electricity. When a signal is detected, it deploys its one extraordinary trick. Two pairs of elastic ligaments hold the jaw assembly locks under the skull,

preloaded like a crossbow. And when triggered, the entire jaw fires forward. at more than three meters per second. This strike was first filmed in 2016 by Professor Nikaya, and it was over in less than a quarter of a second. Quite literally blink, and you'd miss it. And that matters at 1,000 meters. Food is so scarce that every calorie has to be accounted for.

Every predator runs a sort of energy budget. You spend calories hunting, and you need to recover more than you spent from whatever you catch. In shallow water where prey is abundant, an active hunting strategy pays off. But down here, the sums don't work that way. A sustained chase at this depth would burn far more energy than the meal at the end could ever replace. The goblin shark solved this problem by eliminating the hunts almost entirely. It burns almost nothing waiting.

It burns almost nothing striking. The jaw does the work in a third of a second, and then the shark goes back to doing nothing. an approach that's proved more reliable than speed, strength or stamina ever could. But how does it get away with being, well, so bad at everything else? On a coral reef being big and slow as a death sentence. Predators keep animals fast, sharp and small, and that evolutionary pressure shapes everything about how life looks in shallow water. At 1,000 metres, that pressure almost disappears.

It's cold, it's dark, and food is genuinely scarce. but danger is rarer still. That's the goblin sharks secret. It didn't survive by being the best predator in the ocean. It survived by finding the one place on earth where being slow, soft and half blind is absolutely fine, provided you can do one thing faster than anything else alive. But yet again, there is so much more to this tale of deep sea giants.

Go deeper, 3,000 meters deeper, and the monsters get even bigger, even we're talking about a giant trailing arms 10 metres long through the darkness. Meet Stigio Medusa Gigantia, the giant phantom jelly that lurks in the midnight zone. It's named after the river sticks in Greek mythology. The cold, dark river that connected the living world to Hades, the realm of the dead. It's bell, the umbrella-shaped body we might call her head, is about a meter across. From it, trail four vast ribbon-like arms,

each roughly the length of a double-decker bus. These are not tentacles, not fine stinging threads. They are thick, muscular curtains of flesh, drifting through total darkness, covered in mucus that traps anything that drifts into them. When prey makes contact, those ribbons curl inward, and the bell itself stretches to nearly five times its resting

size to engulf it. This footage comes from an expedition to the Gulf of California, where the Monterey Bay Aquarium Research Institute, Embari's ROV, saw its predatory tactics firsthand. This animal competes with squid, deep-sea fish, and with whales for food, and it does so without a brain, without a central nervous system, and without anything we would recognize as a control system at all. But leave one on a beach and it would almost evaporate. Try to haul one up in a trawl net and it turns to goo,

which is actually a clue into its giant existence. Here's where this stops being spectacle and starts being physics. At sea level, roughly one kilogram of pressure pushes down on every square centimetre of your skin. Go underwater and you add another kilogram for every 10 metres of depth. At 1,000 metres, that's 100 kilograms per square centimetre. to bearing down on everything. At the deepest confirmed sightings of this animal,

somewhere beyond 6,000 meters, the pressure is equivalent to 620 kilograms focus on an area the size of your thumbnail. At similar depths, submersibles have imploded fast than the human brain can even process sound. So how does a 10-meter brainless curtain of jelly survive where engineering doesn't?

Well, by having nothing to crush. pressure destroys air pockets, rigid skeletons and sealed chambers. It finds the gaps in it squeezes. But Sidgio Medusa has none of those. Its body is roughly 95% water and waterler is virtually incompressible. The pressure inside its tissues equalizes instantly with the pressure outside. There is no air pocket to collapse, no rigid structure to buckle, no sealed chamber to implode.

There is nothing to crush. to crush. Other deep sea creatures have the same problem. They can't rely on gas-filled spaces for buoyancy, structure or breathing. Instead, everything that lives here is either mostly water or other chemical alternatives. Cold water pushes growth. Low predation allows it. Extreme pressure eliminates anything rigid enough to snap. And what's left, what survives all three forces simultaneously, is something the shallow world simply cannot produce. Now so far up to this point, each giant we've encountered has been shaped by one force or two. But what comes next is shaped by all of them, at once and turned up to full power.

A creature that also looms large in mythology. In Japanese folklore, the orfish has a name, Ryugu no Tsukai, the messenger from the sea god's palace. In the west, we call it something less poetic, the doomsday fish. The legend tells that when these animals surface, it's a sign of danger from the deep, a foreboding alarm signal for an earthquake, a tsunami, something catastrophic from below. And this isn't a fringe belief. It's a century's old superstition in a country that sits on the Pacific Ring of Fire and has learned the hard way to look out for patterns in nature.

And the data, if you squint, is uncomfortable. In 2009 and 2010, around 20 oarfish washed ashore on Japanese beaches. In March 2011, the Tohoku earthquake and tsunami killed nearly 18,000 people. A 2019 scientific study examined the correlation and concluded it was almost certainly coincidental. The sample sizes were just too small, the timeframes were too loose, but it's not being completely ruled out. The oarfish lives at depths of 200 to 1000 metres, right at the level where seismic activity disturbs the water column most severely. Some researchers have suggested that pre-earthquake geological stress releases gases and changes pressure gradients at depth, potentially disorientating deep-sea animals and driving them upwards.

They are blade thin and silver from head to tail, with a crimson fin running their entire length. This creature has no scales, no teeth, and is the longest bony fish alive. The largest specimen ever properly measured came in at 8 metres, but we don't actually know how big it can get. There are credible reports of 11, even some accounts, of 17 metres. So why can't we be more precise? Well, almost every orefish we've ever found was already dead or dying when we reached it. They're so fragile on the surface that their bodies deteriorate within hours of.

surfacing and their skin is so soft it falls apart on contact. And crucially, as we'll see in a moment, most specimens arrive already missing their tails. So up to this point, we've only be measuring stumps. Some scientists actually managed to film a living orfish in its natural habitat in 2010, just off the Gulf of Mexico, by a remotely operated vehicle that happened to just be in the right place at the right time. Scientists estimated the individual was around 10 meters, but it could grow considerably longer, and we would have no way of knowing. All fish hang vertically in the water column, tail pointing straight down perfectly still, like a silver exclamation point in total darkness.

They filter feed on krill. In fact, one specimen found off the coast of California had 10,000 krills in its stomach. That's two small cereal bowls full of tiny shrimp for a creature twice as tall as a giraffe. Three quarters of the oarfish is tail. Everything vital to life, heart, organs, reproductive system is crammed into the front quarter and the rest is in a very real biological sense expendable. Orfish regularly and deliberately amputate their own tails. Sometimes just the tip goes, sometimes more than half.

Sciences call it auto-tummy or self-cutting, and they don't fully understand why this happens. With no confirmed predators, it's unlikely the or off-o-tummitter. is borrowing the same trick lizards used to escape a predator's grip, for example. But unlike lizards, the tail doesn't regenerate. Whatever is lost is gone permanently. And yet, the oarfish keeps gaining mass regardless. As a teleost fished, it carries the same open-ended growth biology shared by most of its relatives.

No programmed ceiling, no instruction to stop. Nobody has ever found the upper limit. The Orfish is a textbook case of everything we've learned so far about deep sea gigantism. Cold water slow cell division. Pressure eliminates anything rigid. Scarcity demands maximum energy efficiency and the near total absence of predators removes the one force that keeps everything else small. Every condition that makes the deep sea hostile to life has in this animal been flipped into a growth advantage.

It gave up warmth, food and light for something the surface could never. offer, the freedom to just keep going. And there is one last mega giant that evaded science for more than a century. An animal so elusive that everything we know about it came from fragments pulled from the stomachs of whales. It was only in 2025 that a team of scientists finally saw one alive for the first time. And what that footage showed stopped them in their tracks. March 9th, 2025.

A remotely operated vehicle called Sebastian is 600 metres down in the South Atlantic, near the South Sandwich Islands. The cameras pick up something nobody on board had dared to hope for, a living colossal squid. We first encountered this animal, the heaviest invertebrate on the planet, in 1925. Well, a piece of it anyway. A pair of arms were found inside a commercially hunted sperm whale. Over the following century, only eight adult specimens were identified, almost all within other animals caught accidentally in fishing nets. Yet, despite that, we still know a remarkable amount.

The colossal squid has the largest eyes of any living creature, up to 27 centimetres across, and roughly the size of a soccer ball, evolved to detect the faintest traces of light in the permanent darkness of the deep. Its blood runs blue. Because where our blood uses iron to carry oxygen, the colossal squid uses copper, a molecule called hemacionin that works more effectively in cold, low-oxygen water. But perhaps the most surprising feature is its brain. It's shaped like a donut, a ring of neural tissue with a 10-millimeter hole punched through the center.

But that hole is not a design floor. The esophagus, the food pipe, passes directly through the middle of the brain on its way to the stomach, which means every mouth of the food the squid swallows has to fit through that 10mm gap. When the fully grown 500 kilogram colossal squid gets its prey wrong and swallows something too large, the food physically compresses the brain on its way through. Too big a mouthful isn't just indigestion, it's neurological damage. Dr. Kat Bollstad of Auckland University of Technology had spent over two decades studying the

colossal squid, but had had to be a lot of the colossal squid. never seen it in its natural habitat until March 9th 2025 when her team's remotely operated vehicle Sebastian caught the first living sighting of the squid in the deep ocean and one thing in particular stood out chromatophores now certain cephalopods like this short fin squid for example have large rusty red-brown structures scattered across their mantle these are chromatophores chromatophores or colour-changing cells. These animal, which for a long time we thought were simply transparent, can switch at will from being a perfect ghost in the water column to being completely opaque. In the total darkness of the deep ocean, where bioluminescent flashes are the only light source,

the ability to appear and disappear on command may be how these animals hunt and survive. So far the colossal squid fits in quite well amongst its fellow deep sea giants, but there's one factor that throws a major spanner in the works, and it's its lifespan. Many deep sea giants live for a long time, tens or even hundreds of years, but the colossal squid is different. Scientists calculate the age of a squid by reading growth rings inside its statoliths, tiny balance organs inside the squid's head, roughly the size of a grain of sand that lay down one microscopic,

layer every single day, a bit like tree rings. Based on this method and the phenomenal growth rate it implies, scientists believe the colossal squid lives for only around one to two years. Yes, that means it grows from 30 centimetres to more than half a ton in roughly the same time it takes a human child to learn how to walk. So what's driving this explosive growth? Well, to find out, scientists had to go sideways, because the colossal squid's own genome has never been sequenced. What we do know comes from its relatives, the cephalopods. Think of DNA as a master recipe book. Locked in a vault, never changed. Now, before any recipe gets used, the cell makes a working copy. That copy is called messenger RNA, and in almost every animal on earth, that copy is exact. What the DNA says,

the RNA delivers. Cephalopods, though, do see. something different. They edit the copy. Not randomly, not accidentally, but in response to whatever conditions they're currently facing, whether that's freezing temperatures, crushing pressure or total darkness. No matter what it is, the RNA gets adjusted and the protein it builds changes with it. In humans, less than 1% of the brain's genetic instructions are rewritten before the cell acts on them. In cephalopods, over 60% are. Whether the colossal squid uses this same trick to drive its explosive growth rate is one of the big questions scientists still don't have the answer to. But one day, I'm sure they will, and I for one, can't wait to find out.

So why does this all matter? Well, firstly, it's cool to look at weird and wonderful creatures. Yeah, but secondly, because every single one of us is in a race against time. Our cells divide, our telomeres, the tiny protective caps on our DNA, like the sort of plastic tips on your shoelaces are slowly wearing down. Damage builds as we age and eventually systems fail, whether through cancer or other diseases. And for all the brilliance of modern medicine, we are still largely fighting these battles with tools developed from organisms that live, as we do, at the surface. But down in the deep, evolution has been running different experiments for hundreds of millions of years and we were only just starting to read the results. Take the

squid's RNA editing. Cancer is at its core a disease of uncontrolled cell division, cells receiving corrupted instructions and then acting on them. So an animal that can edit those instructions in real time, switching protein structures on and off in response to its environment, points to a completely new way of thinking about cellular control. Scientists right now are actively investigating whether similar RNA editing mechanisms could be harnessed to correct the corrupted molecular signs that drive tumour growth. Or think about what the deep sea has already delivered. In 1990, researchers at the Scripps Institution of Oceanography scooped sediment from the ocean floor off the Bahamas and found a previously unknown deep sea bacterium called salinospora.

From it, they isolated a compound now called marizanib that can do something no existing brain cancer drug can. It crosses the blood-brain barrier. It's currently in the final stages of clinical trials for glioblastoma, one of the most untreatable cancers known to medicine, and it's not alone. Twelve marine-derived compounds have already received FDA approval as cancer treatments, with 34 more in clinical trials. Giant isopods, the animals that can survive five years without food by dropping their metabolism to almost nothing, have the potential to inform research into metabolic disorders, organ

preservation, and potentially the psychological challenges of. long duration space travel, where the human body must be sustained with minimal resources for extended periods. We came looking for monsters in the dark, but what we found were biological breakthroughs, animals that push back against aging, resist disease and grow to impossible sizes using molecular tricks, we are only just beginning to understand. The deep ocean isn't just the last frontier for exploration, it may well be the last frontier for biology too, too, and I personally can't wait to keep exploring. Let me know in the comments down below. Which of these creatures do you love the most? Did we miss any from this list? And perhaps most

importantly, which ones you think might still be out there waiting to be found?