ExtinctZoo - The Prehistoric Giants They Don't Teach You About In School

Episode Date: February 7, 2026

Whenever you watch a documentary about prehistoric life, you expect to see some giants. However, have you ever noticed that the giants your shown, are more or less always the same ones? Well, today your gonna learn about the giants that they don't show you.

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Monopoly is a trademark of Hasbro. Hasbro is not a sponsor of this promotion. Fierce, giant, and extinct. When I say those three words, what do people typically think of? Well, they first may picture a dinosaur of some sorts, perhaps a T-Rex or some kind of sarapod, but then if I say, no dinosaurs,

one then might move on to a giant pterosaur, mosaore, Crock, Mega Shark, a giant from the Ice Age, etc., etc. The point is, when we talk about giant prehistoric animals, there are a few that pretty much always come to mind, leading to documentaries and movies frequently featuring the same type of animals on repeat. However, because of this focus, certain giants on Earth throughout the years have been found, which simply have fallen to the sidelines,

overshadowed again by the quote-unquote fan favorites. And personally, I think these forgotten faces need a little love too, as if you really look through history, you'll find that there are many giants walking about that most people have never heard of, let alone seen. And I'm not talking about unknown animals that belong to groups that are already well known for being huge. Instead, we're going to be taking a look at animals that, hopefully, view didn't know existed in nearly any sense of the word, as seen with this specimen, now known as the Beast of Lesotho. If you have heard of this before, your paleo lore is king-like,

and perhaps you don't need even watch this video, but stick around anyway. Now, for everyone else, what exactly is the Beast of Lesotho? Well, An amphibian like no other, that's what. For hundreds and millions of years, from the Carboniferous all the way up to the Cretaceous, one could say that the realm of amphibians was pretty much dominated by just one group, the temnospondalai, who had been found all over the world and came in virtually every shape and size, with some being teeny tiny and others absolutely giant. And so this order was extremely diverse, with one way of thinking about them is that they're pretty much the mammal equivalent of the placentals.

So unsurprisingly, there were multiple large families that made up the temnospondalai, and one of them was the brachyopidae, a family which specifically emerged during the final days of the Permian, and were quite successful up until the Jurassic. The members of this group, just like the order, varied in size and location. But they were all carnivores, who are believed to have lived a lot like crocodiles, being opportunistic hunters, only restricted in diet by their size. And for many years, amphibians from this family were regarded as having been small to medium-sized, not massive, until that is a fragmentary piece of a jaw was found in South Africa that seems to have changed,

everything, as this mouthpiece was huge. Now, it has not been confirmed if it belonged to an already identified genus, or rather represents a brand new one, but either way it has been classified to have come from a brachiopidae. And when comparing this jaw piece to related members, we come to the conclusion that this guy might have reached seven meters or 23 feet long, which, for comparison, the largest amphibian alive today, the Chinese giant salamander, is only 1.8 meters or 5.6 feet long, so not even a third of the length. And the beast of Alistu, as it was aptly named, wasn't just long, but also ridiculously chunky and robust, having had a whopper of a mouth that could possibly swallow even a human-sized prey whole,

and also weighed multiple tons, the body, that is, not the mouth. Currently, it's believed to have lived in the waterways of the Elliott Formation during the very early stages of the Jurassic, where it there might have terrorized numerous kinds of animals in need of a drink, including multiple theropods, smaller cyropodomorphs, and ornithicians, among others. And so far, it's actually the largest known carnivore from the entire formation, dinosaurs included. So, so much so for this being the age of dinosaurs. But with this said, I will mention that obviously the jaw piece is fragmentary, so it remains to be seen just how accurate its body size estimate is. However, even if the beast of Lesotho does turn out to be a bust,

it's still fine because we actually have other obscure giant amphibians too, such as the possibly longer, albeit lighter built, Pranusucas, which hailed from Permian Brazil, or the alligator-headed mastodon-saurus from Triassic Europe, which could have exceeded six meters or 20 feet and also held a more robust build and made a great living by feeding a large fish as well as others of its own kind, seeing that evidence for cannibalism amongst this two-ton plus creature is very much known of. So the next time a show or documentary wants to make a certain area come off as a bit horrifying, I say we go with a giant amphibian. They're just that dang cool.

And you know what else is cool? A giant animal that looks like a dinosaur, but wasn't. And it's something most people have never heard it before. And so, what am I talking about? Well, none other than the Silasukas, of course. Now, if you're an avid watcher, you might remember this guy, but I still feel like this is a relatively unknown creature on the grand scale of things, which is honestly shocking when you realize that this was the largest animal to ever stand on two legs

that was not a dinosaur. And yes, it can be hard to believe that this was, in fact, not a dinosaur, but it really wasn't. Instead, what you're looking at is a type of popsauroid, who were essentially in advanced cladisudosukians that were one of the Earth's most abundant animals during various parts of the Triassic, and are generally known for having been a bit unusual, with some having sails, others being robust quadrupeds, and then some, like the Silasukas, walking around on two legs. The Silasukas specifically belonged to the Papasaur family, the Shuvosauridae, and, perhaps not shockingly, it was its largest member, as well as being one of the largest non-dinosaur

of all time, as specimens show signs of getting up to 10 meters or 33 feet in length, which, by the way, is longer than your average fully grown allosaurus. And again, just to reiterate, this was not a theropod. And what makes this animal even more unusual is that despite resembling a megatherapod, which would thus make you assume that ate meat, was really just a friendly giant, well, as far as taste buds go, as it was a beaked, toothless herbivore that grazed from trees, sort of like a two-legged sarapod. And coincidentally, it actually lived, lived alongside Sarapods 2, or at least Sarapodomorphs, as this beast hailed from the Triassic Istiguelasto formation of Argentina, which was home to multiple dinosaurs, yet none were absolute giants

just yet, leading to the Silasukas likely being the largest animal within the environment. And though much more famous, I should mention that its more carnivorous relatives could also be equally massive, as you did have pseudosukians like the Solosuchus, which were just as long, but a tad bit more toothy and angry, probably specializing and feeding and on multi-toned sarapotomorphs. In fact, it even seems that the Solosucas might have been the biggest terrestrial predator ever discounting dinosaurs, and the largest fully land predator to walk on four legs. And so, given its attributes, it's not that surprising that it recently even got its own

Hollywood debut in the movie 65, but I should mention that it didn't actually really live 65 million years ago as the movie title would have you believe. Rather, like the Solosucas, it lived during the late Triassic. But you know what is still waiting for a shot to being a movie big bad, a creature that I think would make for a great jaw's replacement, the Nothosaurus. This was just one member of the often forgotten about order of marine reptiles, which were aptly named the Nothosaurus, and who lived all across the world's oceans for much of the Triassic period. And they were in many ways superficially similar to the Pleasiosaurus,

having long body plans, elongated necks, fore limbs, and grass-out builds. And typically they even shared a similar diet, with many members using needle-like teeth to catch fish, amongst other similar animals. Yet, for the most part, they've remained much more unknown to the general public than their distant relatives. And I think this has something to do with the pleasiosaurus being much larger, as typically Nothosaurs weren't that big, usually maxing out to 2 meters or 6.5 feet. So, large enough to give you a heart attack in the water, but probably not large enough to the point that it would have actually bothered you.

However, this notion about their size has slowly started to change, after the discovery massive specimens which hailed from Triassic China and Europe. And these new specimens, often made up a portions of the fate, and varying teeth show that two species, no the story as gigantes and jengi, could measure up to 7 meters or 23 feet long, and were structurally much more robust than their fellow kin. Leading researchers believe that fish wasn't the only grub that these species were restricted to. In the case of the Zhang Gees specimen, it's even thought that the current estimates are too low, and that it really might have been able to reach greater lengths.

Now, admittedly, we have been kind of spoiled in the realm of marine giants, thanks to the likes of the Megalodon or predatory whales. But don't forget, even as 7 meters, the Nothosaurus is one of the largest marine predators that wasn't a whale, mosesaur, pleasaur, ectheosaur, or shark. And that might sound like quite the list of exclusions, but remember just how many groups have lived in the ocean. And what makes the Nothosaurus a little bit more crazy is that unlike its lookalike, the pleasiosaurus, it was apparently a semi-aquatic creature that you could find not only in the water, but also lurking on the beaches. So, if you don't mind sharing the sand with a predator longer than a tiger shark,

which also is a face like this, then the Nothosaurus might just be the animal for you. And like I said, the Nothosaurus hailed from the Triassic period, which, just like a few others talked about so far. And so, I would say that the Triassic as a whole has gone somewhat under the radar when it comes to giants. Is it had more than just a few? And amongst the lot, there was one terrestrial tank that is almost never talked about, despite it possibly being the largest land animal ever, once you exclude dinosaurs, proboscideans, and rhinos. And again, almost no one knows about it. And this was the Liso Vicha. Now, a partial reason to why it's so unknown is that relative to many other genera, it was only recently discovered, or at least only

described, with that happening only in 2019. However, the bones belonging to it were actually unearthed a bit earlier back in 2006, after researchers in Poland found a variety of different bones outside the village of Lysavitsa. And these bones were massive, and were of such stature that at first the scientists assumed that they could only have once belonged to a large sarapotomorph. Yet after they found over a thousand more bones, this time with pieces of skull material, they understood that in reality they'd assembled upon a new kind of disinodont, making it a member of the extinct animadante acclade. And, by the way, non-mammalian synapsed at that.

With this said, this group had been a long-known staple of the Triassic, and large gener already known from it, such as the Istrogolostia, a genus, unsurprisingly from the Istrioloste formation of Argentina. which I previously mentioned. And this genus could weigh up to one ton and stand nearly as tall as a person. Yet the Lisa Vicha was on a completely different level, making all those before it appear small, with their hips alone standing at over 2.6 meters or 8.5 feet tall,

while its body stretched out for over 4.5 meters or 15 feet. And that's the actual body, by the way, not including the tail, saying that, well, it almost didn't have one, being just pretty much pure mass. And since it was essentially an oversized blob, its bones were absurdly robust in construction as well, which altogether put the Liso Vichia at possibly nine tons in weight, making it on par with modern-day elephants, and even heavier than some of the most famous dinosaurs, such as the psychosaurus, and chalosaurus, and obviously

more. And remember, this guy was from the Triassic, and so, given its size, it's also considered by some to open the largest animal to ever walk up until the evolution of large sarapotomorphs, so pretty metal. But fret not any would-be time travelers, as this guy was not a the carnivorous. As like its fellow obscure giant, the Silasuccus, Lisovica was a toothless beaked herbivore that used its beak to snip and chew vegetation. And we know from located coprolites, i.e. fossilized dung pieces, that most of its diet was composed as softer plants and conifers, while some of its snacks could then also be made up of woody material. But despite being a green lover, I would still recommend some heavy caution around the sky, as it was, once again,

built like a literal tank, and had one thick bony head that I'm sure could dish out some pretty impressive damage if it got a hold of you. I mean, if a camel is able to essentially bite someone's head off, I certainly don't want to know what this dicinidon could do. But with that said, its massive size was not a foolproof defense during the Triassic, as there are in fact signs this animal's preyed upon, with bones showing bite marks that seem to have come from another somewhat obscure giant, the Smok Vavelsky, which yes is its actual name. Now this was a decently sized archaosaur from late Triassic that looked like once again it could have been a dinosaur or perhaps an unusual Rawi Sukkid. But for now we don't know which of these it actually was,

only that it was quite big for the time, measuring six meters or 20 feet long, which when you need to build up your team to handle the growing chaos at work, use indeed sponsored jobs. It gives your job post the boost it needs to be seen and helps reach people with the right skills, certifications, and more. Spend less time searching and more time actually interviewing candidates who check all your boxes. Listeners of this show will get a $75 sponsored job credit at Indeed.com slash podcast.

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It matters where you stay. Hilton, for the stay. In fact, makes it the largest known predatory arc of store from Europe during not only the late Triassic, but all the way up until the early Jurassic, too. At this point, everything I've talked about has not been something that we are. And that would be a mammal. And so this could have you feeling a bit left out.

And truthfully, I do think finding some obscure mammalian giants is a bit tricky, as many tend to be the same old same old. I mean, I guess you could say that the Parasarotherium or the Paleoaxedonomaticus are both somewhat obscure giants, being 10 plus tonned behemoths, but one was a proboscidian and the other a rhinocerotoid, two groups which are not obscure and are very well known for being big. So, at least to me, I wouldn't say that they're that obscure. Then there are also some other groups that I would say it compose of obscure genera, but as a whole are, well-known, which includes many groups from the Ice Age, like the giant ground sloths, armadillos, and so forth. Yet, with all of this said, there was one group that did stick out to me, as they aren't as famous as the Ice Age animals and reach sizes that, frankly, even I, wasn't aware of.

And that would be the Brontothairnay. If I could sum up this group of extinct paracetyl in just a few words, it'd be the rhinos of old. However, in reality, they only superficially looked like rhinos, not being close relatives at all, instead being slightly more related to horses, where their shared appearance simply coming down to convergent evolution. I guess a tank-like body, dense hide, and a large bony nose horn that you can ram things with is a pretty useful combo no matter when you evolve. And as a whole, just like the rhinos, this group became highly successful, existing for over 20 million years during the Eocene period and expanding throughout large portions of Europe, North America, and Asia, where it's believed they lived in large herds and inhabited warm,

moist, wooded, and forested areas. Now, those who've actually researched these animals have long known that they harbored giants, and for a good duration of time, the known top dog, or Brontophir, was believed to have been the Megasarops, an obscure giant amongst its own kind that stood 2.5 meters or 8.2 feet tall at the shoulder, and was over 15 feet long when you include its albeit short tail. It specifically hailed from North America during the late Eocene, and was actually one of the first terrestrial animals in the planet to reach five tons following. the demise of the dinosaurs. And at this size, plus, given the predators that were around, it's thought that adults might have been untouchable, having no natural predator. And I'm sure

it certainly helped that they also look quite menacing thanks to their very distinctive double horns. But here's the real crazy part, because despite being absolutely giant for a mammal, the mega serops might not even have been the largest prontothere, and it's possible that it wasn't even close, as the lesser-known genera could have it beat, and that is the Ambelotherium. This was in fact a very closely related genus that was actually slightly older than the Megasarops, having lived in EOT Mongolia about 3 million years before the megacerops would evolve. And this guy isn't exactly new, and in fact, it's always been suspected that the embellotherium was a larger brontothera.

However, the talk about it being the largest ever only started happening after the discovery of a Titanic skull back in the mid-70s, as the partial skull was found that alone was over four feet or 1.2 meters long, possibly even a bit longer. making it not only greater in length than the skull of modern-day elephants, but also comparable to certain kinds of large theropods. So, it was obviously clear to the researchers that they had a monster on their hands. And though it's nigh impossible to tell just how big the specimen was without the rest of the body, some estimates have speculated that this Noggin belonged to a nearly nine-ton individual that was anywhere from 18 to 20 feet long or 5.4 to 6 meters,

while standing tall enough that if you're right next to one, you'd have to look up straight into the sky to see its face. And besides being absurdly large, another interesting trait about this brontefeer that was a bit unique, was its horn, as it had evolved into one large structure that more resembled a battering ram than anything else. And this originally led to the notion that, like a ram, the emblemotherium would use this structure to bash not only any threats, but also each other during interspecific competition. However, when actually analyzing their rams, paleontologists noted that compared to relatives, theirs was actually much thinner and hollower, leading to the new idea that they were, weren't used as weapons, but rather means to communicate, possibly even helping to resonate

certain sounds, whilst their absolutely gigantic size was likely more than enough defense by its lonesome. So there you have it, one obscure mammalian giant. But funny enough, the Ambulotherium, or even the Brontotheras as a whole, are not the only ones. There are others. And if we switch specifically to the realm of carnivores, one that is quite shocking is a species that actually is a decent shot in the title for the largest mammalian predator of all time. Well, that isn't a whale. And this mystery animal is somewhat tied to what I consider an actual living obscure giant. And that would be walruses.

Now, obviously, most people have heard of walruses, I'd hope at least, but many don't know just how big they truly are. And so, to put their size into perspective, large males are often twice or three times the size of freaking polar bears and have megatusks that can each measure up to 100 centimeters or 3.3 feet long. And yet, despite being this massive, living walruses are actually pretty much the littlest of bros, so you could say. As in reality, there was a much larger, now extinct kind of walrus that once thrived, which didn't just outsize extinct walruses, but again is also a contender for the largest carnivoran to ever live. And its name, Pontolus Magnus.

To find this beast, you'd have to travel back to the Miacin period some 12 million years ago, a time when prehistoric oceans in general were much scarier than current. housing not only iconic extinct giants such as the Megalodon, but also similarly sized predatory whales that belonged to the ficotorodia, amongst others. And included in these others was our protagonist, the Pontilus Magnus, which was an absolute giant in its own right, having a body that extended for over four meters or 13 feet long, while also weighing up to four tons, the same as a male Asian elephant, whilst the larger specimens might have even exceeded this.

However, let me emphasize, this was not an elephant, but rather a walrus. a four-ton freaking walrus. Additionally, while Asian elephants like their greens, Pontolus Magnus was pretty much Ron Swanson, meat only, having been an active predator. Yet, as opposed to living walruses that have their tusks, the Pontolus actually lacked these features, having traded them out for a Titanic skull

that was twice the size of the head of extant walruses. And within the Pontolas school, you would have found them filled with large, powerful teeth that were designed to pierce and crush megafaunal prey. So, this is all to say, that Pontolus Magnus was one pinnipid that might have taken a very unwelcome interest to a human, assuming obviously

if we had been around during its heyday. And if the Pontolus Magnus was still alive, it probably would be an actual problem. As unlike extant walruses that inhabit more remote regions of the world, the magnus preferred areas that today are quite densely populated, having been found mainly along the western coast of the U.S.,

from California, all the way up to Oregon. And in these areas, it's thought that it likely hunted other penipids, such as seals, while crabs, birds, smaller cetaceans, large fish, including, by the way, Megalodon Pups, and possibly members of the only extinct Marine Order, the Desmostalians, who I've actually made a video about, so if you haven't seen that, go check it out. And definitely do not think that just because it was chunky, that you would have been able to out swim this creature. Because remember, the walrus also looks like it wouldn't swim that well.

And yet, despite appearing morbidly obese, are capable of swimming in bursts up to 35 kilometers per hour or 22 miles per hour, which is more than three times faster than Michael Phelps at his highest recorded swim speed, and quicker than the average person can sprint. And we're not talking about Jesus, so on land that is. And so, it's animals like the Pontolus Magnus, who really reinforced the idea that large open expanses of water, i.e. seas and oceans, are no-bueno. However, freshwater also has harbored its fair share of obscure giants, multiple, in fact.

I mean, have you ever seen the show river monsters? And one prehistoric fish that exemplifies this point pretty well is the rise of it. Now, I would say this creature somewhat teeter than the line between obscure and somewhat known. However, its case is still pretty interesting as we are talking about a predatory freshwater fish that was larger than a freaking great white, and not, I repeat, not a shark. Instead, it was a wait for it, rhizodont, a group of lobefinned fish, of which the rhizodot was the largest member, and by a decent margin at that, with some specimens of this giant fish, apparently measuring up to seven meters or 23 feet long, while weighing potentially one point

making it a contender for the largest freshwater fish of all time. And perhaps not surprisingly, it was during the Carboniferous, the age of amphibians and creepy crawlies, when this fish lived, inhabiting the dense woodlocked rivers and streams of North America, England, and Russia. And given its size, it likely hunted fair-sized fish and tetrapods, and would have done so with the help with some pretty narrowly teeth, as each risadus came equipped with enlarged tusks or fang-like teeth that could grow to be longer than the tooth of a literal T-Rex, and implied that instead of being limited to swalling animals whole, the risadus could absolutely attack,

kill, and then rip prey apart into more bite-sized bites. And just to make this giant even scarier, paleontologists noticed that its frontal fins were, in fact, even more developed and powerful than its back ones, leading to the notion that even on the water edge, you would not be totally safe, with the idea being that much like a crocodile or alligator, the risadus could actually lunge the animals along the shoreline and surprise attacks. So, one second you're looking at your beautiful reflection in the water, and then the next there's a face as big as your body gobbling you up. So just one more thing that makes the Carboniferous an absolute nope for me. However, this was not the only time where freshwater harbored forgotten giants,

as if you traveled to the Cretaceous, you would have found an even lesser-known animal that was just as, or possibly even bigger than the risod is, and that would be the masonia. Statistically, chances are you've never heard this guy before, but you might know the group of fish it belongs to, the celicants, who made some buzz a few years back for quote-unquote reappearing after having been extinct since the late Cretaceous. And while we obviously know that it is now wrong to have called this group extinct, it is still accurate to say they were better off during the Cretaceous, as along with being more diverse, they were also more widespread.

And the Mawsonian particular is known to have come from both brackish and freshwater rivers found throughout South America, Eastern North America, and Africa, where it actually co-existed with the infamous Spinosaurus, who, statistically, you are likely to know, and was one of the largest theropods to ever live. However, we're obviously here for the fish, not the dinosaur, and while it wasn't as big of the spino, the masonia was still giant.

Measuring up to 5.48 meters, or nearly 18 feet long, which is longer than the average giraffe is tall. And while this is obviously not as long as the risadus, what might have given mosconia the edge in sheer size was its weight. As opposed to the former, masonia was much thicker all around, and the largest specimens might have cracked two tons.

And not to mention that some speculate, that given the size variation seen in celiacanths today, a six meter or nearly 20 footer might be out there too. And so this all begs the question of what is the celicant that weighs more than two polar bears smashed together, eat? And the answer is, we aren't so sure. As based on recovered teeth, it's possible this fish had a preference for some crunchy texture,

being durifagous and eating hard-shelled animals, such as large crabs, snails, and more. But then there is a bit more unnerving idea that Mawsonia fed like a Goliath grouper, which basically means that it was an oversight. Kirby, using powerful suction to gobble up pretty much anything that fit in its mouth. And considering that the much smaller groupers have been documented vacuuming up five-foot sharks, I shuddered to imagine what would happen if a person had swum too close to the masonia.

So, perhaps just best to stay far away. And ultimately, the masonia wasn't the only relatively unknown giant from its environment. There were plenty more where that came from. And so this is all to say that while we all have our fan favorites when it comes to giant prehistoric animals, they certainly were not the only ones. And if this video gets enough likes, there will certainly be a part two. Thanks for watching.

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