The Only Time In History That Blue Whales Weren t The Biggest

This is a blue whale, and by raw mass, this is the heaviest animal to ever have stepped fin on the planet. Or so we thought. At over 80 feet long and weighing 200 tons, the blue whale was supposed to be the largest possible animal that could exist. Not because evolution didn't get the chance to make anything bigger, but because there literally couldn't be a bigger body before the laws of physics would cause it to collapse under its own weight and die. The blue whale exists right on the edge of what is biologically possible, the absolute maximum capacity of animal. That was until we found this jawbone. This is, or was, the Ichthyotitan, and it is the only time in history that an animal grew large enough to actually challenge the blue whale for the title of largest animal ever. And strangely enough, this animal wasn't even a whale. So how big actually was this creature? And why did it go extinct? Well, to understand how large this thing was, let's first agree on what large actually means. Usually when people ask what's the biggest animal, they're talking about mass. Wait, the sheer amount of biological matter taking up space. Because if we were judging by length, the blue whale actually loses to a bunch of animals already. The Argentinosaurus was a dinosaur that measured around 115 feet long, easily beating the whale in a measuring contest. But a huge chunk of that length was just a skinny neck and a whip tail. It was basically a walking suspension bridge. It weighed maybe 80 or 90 tons max, which is still really heavy. The blue whale is double that. And if you want to get really technical, the bootlace worm can reach 180 feet long, but it weighs about as much as a wet sock. That's not actually giant, that's just a really long piece of string. The blue whale is the number one because it has a lot of whale in it. It is a solid 200 ton block of meat and blubber. So how big was the Ichthyotitan? Estimates put it at about 85 feet long, but it wasn't just a skinny noodle trying to win on a technicality. This thing was also thick, really, really thick, about 120 tons thick. But does this mean it's lighter than a blue whale? I know I said blue whales were 200 tons and we're going off mass, right? Well, yes, but actually no. Stay with me for a sec. If we look at the official numbers for Ichthyotitan, the estimates put it at roughly 120 tons, which don't get me wrong, is heavy. That's like 13 T-Rexes taped together. But this is the estimate for the largest specimen they found in the UK of the Ichthyotitan. The average estimate for the Ichthyotitan is about 80 tons, still ridiculously massive. But a blue whale is 200 tons, so the whale still wins easily, right? Well, no, because that 200 ton figure is also the upper limit of blue whales. The heaviest one ever found was 209 tons. The average blue whale is actually only 100 to 150 tons, which is the same range as the Ichthyotitan, being 120 tons. I promise I'm not just trying to bait you guys towards a super close match between these sizes. These animals have pushed the limits of evolution and we literally don't know enough about the Ichthyotitan to give a true definitive answer. There's just not that much evidence of them. With blue whales, we have measured thousands of them because, well, they're alive and they're not really the best at hiding. For Ichthyotitan, we have found two, two jawbones. What are the mathematical odds that out of millions of these things that lived over millions of years, we just happened to find the single largest individual to ever exist? Basically zero. But there's another factor that suggests these sea monsters were actually way, way bigger than this 80 ton average. First, there's Aust Colossus. Years ago, before Ichthyotitan was officially named, scientists found a different, much older jawbone in a place called Aust. And for the longest time, this bone was just a mystery. It was clearly from an Ichthyosaur, but it was so comically large that people were hesitant to even classify it. It sat in a sort of paleontological limbo because no one wanted to be the guy who claimed he found a sea monster and turned out to be wrong. But now that we have the Ichthyotitan diagnosis, we can look back at the Aust Colossus and realize, wait, these are likely the same animal or at least the same type of giant and the Aust bone is bigger. This isn't confirmed, but it is the likely guess. If you run the math on the standard Ichthyotitan bones, you get that 80 ton estimate. But if you plug Aust Colossus into the equation, the size jumps to nearly 29 meters long and the weight skyrockets to around 175 tons. Okay, but that's still less than the 209 tons for the biggest blue whale. But again, Aust Colossus isn't, or at least likely isn't the maximum size. So if we take that 175 ton estimate and we treat it like an average large adult, just like 120 ton blue whale, and then we scale it up to see what the maximum version would look like, the math gets stupid. If an Ichthyotitan followed the same growth curve as a whale, where the absolute limits of the species are about 60% heavier than the average adults, the theoretical maximum size for the species wouldn't be 175 tons. It would be closer to 280 tons. Of course, this is just speculation. It's not a proven fact, but it's not necessarily wrong either. Of course, this 280 ton blows away the 209 maximum we found in blue whales, but we don't know if Aust Colossus was actually the largest in the species. We don't know if it even was the same species as the Ichthyotitans. We don't actually know if its weight would actually be carried that way. I mean, what if that jawbone was the entire body and it was just a really big head? Well, we're pretty sure that didn't happen. But whatever the answer actually was, here's the real bottom line. This animal could have been bigger than the average estimates, definitely. And honestly, the most likely chances are that the largest members of the species was bigger than the biggest blue whales. The strange part is, this is actually a really weird case to find in nature, because usually mammals are the ones that get chunky chunky. See, being a whale is actually kind of hard. You're a mammal, which means you have lungs full of air and you're covered in a thick layer of blubber to stay warm. You are basically a giant fleshy balloon. If a whale didn't have a heavy skeleton, it would just bob around the surface like a rubber duck. To actually dive down and do whale things, they need incredibly dense, heavy bones to act as ballast. That's why they weigh so much. Reptiles, on the other hand, are usually built for speed or agility or snapping things in half. If you look at a mosasaur, it's terrifying, sure. But compared to a whale, it's practically athletic. It's long, it's lean, and it doesn't carry around 50 tons of insulation just to keep its internal organs cozy. And Ichthyotitan itself was an ichthyosaur, just a titanic one. But because of this, it was also a marine reptile. Now, I know you're looking at this picture and we're both thinking the same thing. That's clearly a dolphin on steroids, not a reptile. Nope, it's still a reptile, but it's actually not a complete coincidence they look similar. This is just convergent evolution doing that thing where it finds a shape that works and copies it for everyone. Dolphins, sharks, ichthyosaurus all use the same torpedo blueprint because physics basically demands it if you want to swim fast. So why is this reptile so heavy if it's shaped like it wants to be fast? Well, realistically, this reptile's build is actually not very good. I mean, clearly since it's, well, extinct. But in the open ocean, being heavy is how you get fast or at least how you get efficient. See, Ichthyotitan didn't live near the beach. It was fully pelagic, meaning it lived in the deep ocean water far away from land. And when you have to swim thousands of miles across a global ocean, being small is actually a waste of energy. Physics dictates that the larger you are, the less drag you experience relative to your body mass. It's the same reason why a massive cruise ship is actually incredibly efficient at moving across the ocean compared to a speedboat. By becoming a giant 80-foot torpedo or maybe a 200-foot torpedo, Ichthyotitan could cruise for huge distances without burning through its energy reserves. It's the exact same strategy blue whales use today. But getting massive also solves another problem, the cold. Even in Triassic, the deep ocean is freezing and reptiles usually hate the cold. But if you get big enough, you unlock a cheat code called gigantothermy. Basically, you are so huge that your body heat literally cannot escape fast enough. You become a living thermal battery. This allowed them to dive deeper and hunt in colder water. Of course, none of this matters if gravity crushes you. But fortunately, gravity doesn't really work the same way underwater. On land, the structural limit for an animal is around 100 tons. Any heavier and your legs will snap. But in the water, the buoyancy supports the weight. You don't need legs, you just need to float. This is why the biggest land animals capped out at the Argentinosaurus level while marine animals like the blue whale and ichthyotitan could push past 200 tons. But there is one final requirement and the most important requirement for getting big. You can have the perfect body for getting huge, but if there's nothing to eat, you are just going to starve. Luckily, the late Triassic ocean was an absolute buffet. The seas were packed with massive cephalopods, giant fish, and plenty of other marine reptiles. The sheer amount of biomass, just raw food floating around, was high enough to support a predator of this size. And the best part, the penthouse was empty. There were no whales yet. There were no megalodons. There were no mosasaurs. Once ichthyotitan got past a certain size, it had literally zero rivals. Natural selection looked at them and said, get bigger and you win the game. So they did. They became the kings of the ocean. And then they vanished. About 201 million years ago, the Triassic period ended and it didn't end peacefully. It ended with the Central Atlantic Magnetic Prominence, which is basically a fancy name for the earth cracked open and vomited lava everywhere for thousands of years. This released massive amounts of CO2, which caused global warmings, which acidified the oceans. This didn't actually kill them instantly, but what it did kill was the things they ate. And this is where the strategy of being a 200-ton biological submarine backfires. Being huge is great when the buffet is open, but when the buffet closes, also known as getting covered in copious amounts of carbon dioxide, being huge is a death sentence. The ichthyotitan needed millions of calories a day just to keep the lights on. When the ecosystem crashed, the giant starved first. And if you watched our video on the Livyatan and the Meg, you'll notice that you start seeing these patterns for all the extinct giants. They're tough, but they still need to eat. They unfortunately can't break the laws of thermodynamics no matter how big and cool they are. Now, Ichthyosaurus as a group didn't die out completely. They actually survived into the Jurassic, but they changed. They got smaller, they got faster, they stopped trying to be cargo ships and started trying to be fighter jets. And strangely enough, the ocean never made another monster this big again. For the next 200 million years, marine reptiles like Pleiosaurus and Mosasaurs took over. And while they were terrifying and they were big, they weren't Titan big. A Mosasaur tops out at maybe 10 or 20 tons, which is a rounding error for an Ichthyotitan. The niche of Titan at the sea sat completely empty for 200 million years. It wasn't until the mammals decided to return to the water, evolve into whales around 50 million years ago and figure out how to filter feed on krill that the ocean finally saw the true giants of this scale again. The Ichthyotitan was a one-time experiment, a brief moment in history where a reptile reached the limits of physics and proved the blue whales wasn't the only animal to reach 200 tons. It was just the second. Unfortunately, these same reasons mean the Ichthyotitan wouldn't be able to come back today. It would die instantly if it ever came to our oceans because while there are still giant squids and things like that today that they used to eat, they're way harder to find. They're much more rare and they're also buried hundreds of meters deep into the water. Sperm whales have effectively stolen their niche of munching down on the big cephalopods. Honestly, even if food was there, it still wouldn't happen. The harsh reality is that the specific conditions that allowed a reptile to break the game 200 million years ago are gone and they probably aren't coming back. The Triassic was a unique window where the oxygen cycles were unstable, the waters were warmer and the ecosystem was recovering from a wipeout. You also didn't have to compete with orcas or even worse, humans. We are the ultimate glass ceiling for Megafauna. Historically, as soon as humans arrive, the biggest animals disappear. We hunt them, we fish their food or we change their habitats. If a reptile actually managed to start growing to the size of a submarine today, we wouldn't let it rule the ocean. We'd probably just accidentally hit it with cargo ships or hit whatever it eats with cargo ships. But before the ocean turned into what it is today, could there have been something even bigger than the Ichthyotitan that might have not even been a reptile or a whale? Honestly, it's possible. We have found exactly two examples of Ichthyotitan jawbones and one example of the Ors Colossus. That's it, three bones. In the grand scheme of paleontology, that is a statistical error. We estimate that less than 0.01% of all animal life that has ever existed actually became a fossil and we have found an even smaller fraction of that fraction. We are essentially trying to reconstruct the entire history of a library by reading three torn pages we found in the trash. And the fact we did find those bones is actually kind of suspicious. If 200-ton animals were incredibly rare, one in a billion freaks of nature, the odds of us stumbling across their fossils in a random beach in England should be basically zero. The fact that we found them implies they might not have been rare at all. But if we barely found them, what did we miss? Is 200 tons actually the biological limit or is it just the limit of what we've dug up so far? It is entirely possible that buried somewhere under a mile of rock or eroded away by time, there was something else. A creature that lived during a peak of oxygen and food abundance could have been in the perfect conditions to get so big and grow to a size dwarfing even these giants. And then it might have vanished completely without leaving a trace. But for our standards today, whatever this Ichthyotitan creature used to be, it wasn't just a big animal. It was a lost experiment. It was the only time in the history of this planet that evolution not only was able to reach true giant size, much bigger than any megalodons or sperm whales, but also put it into a reptile. The blue whales rule over an ocean that the Ichthyotitan had already conquered over 200 million years ago. We won't see any giant reptiles of this scale anymore, at least not in our lifetime. But maybe it's good that animals of this size today aren't predators. I'm fine with the giants today only going after plankton. Thank you for watching. And if you'd like to see a video on the deadliest whale of all time, meaning it ate other whales and even megalodons, check out this video here.