ExtinctZoo - The Deadliest Sea Animal From Every Single Period

Episode Date: July 13, 2026

The oceans and seas of earth have long been home to some of the most nightmarish creatures, and when you include every aquatic animal ever, the list of thalassophobia inducing animals is pretty long, which made me wonder, what just was the deadliest sea animal from each of earth’s periods?

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I didn't know you could get that big. Spider-Man, brand-new day in theaters, July 31st. One of the toughest and realist bars ever dropped by an honorary paleontologist is no matter how bad things get on land, never get into the water. And what this essentially means is that no matter how horrifying the land animals are, those below the surface are almost always worse. And I'd say this holds up pretty well. I mean, there ain't no chance of winning against a tiger or a lion, but frankly I'm still choosing them over a shark or crocodile any day of the week. And I am for 100% absolute certainty choosing to be dropped in a random place on land, if I had to, versus a random place in the water.

No thanks. And when you dial back the clock, this rule works just as well, if not better, as pretty much every time in Earth's history, no matter when, seems to have had marine animals that were miles worse than the terrestrial predators above. And just like on land, it wasn't only one or two predators lurking beneath the waves. It was a whole lot. And over time, they changed a whole lot. lot too, which got me thinking, if one was sent back through every geological period since the

Cambrian, as that's usually when we consider the first apex predators to have appeared, what exactly would be the worst thing you could swim into from each time? Now, naturally, the answers are all bad, but at first it might not have been as bad as you think, as during the Cambrian which took place over half a billion years ago, life was still gearing up and had not yet reached crack in sizes, let's In fact, during this time, when the world seemed prime for thalasophobia, given the vast amounts of water and fragmented land, most aquatic life was actually much smaller than even a puck. So though there were plenty of creepy-looking things, they would have been essentially harmless to human-sized animals.

Historically, the most well-known apex predator and quote-unquote large animal from this period has been the anomalacharis, a highly strange radiodont arthropod, which at its maximum was around 1.68 feet or 51 centimeters long, and is thought to have to have a very large. have weighed about the same as a chihuahua, but being distinguished by said chihuahua, by compound eyes, two large frontal appendages that were claw-like, and lined with comb rows of spines, allowing it to sweep and grasp or prey. However, with this said, in reality, this weird, shrimp-looking thing was not the real nightmare of the Cambrian, as that distinguishment likely went to an animal far less famous, which for

now is also the largest free-living animal known from this period, the omnidens, meaning large, all-tooth. Perhaps surprisingly, given how Lovecrafty in this creature looked, it too was actually an arthropod, and even belonged to the same class as the anomalacharis, being a dyno-corridida. However, it was not a radiodont, and in some ways we still don't know what it truly was, with one hypothesis being that it was a gild lobopod. On the surface, the omnidens was a soft-bodied organism that was worm-like, fairly flat and heavily sclerotized, a process that occurs when tissue becomes hardened, rigid, and darkened,

forming an exoskeleton of sorts that protected it from other predators and the elements. Now like the anomalacharis, the omnidins also sported two proportionally large frontal appendages that were lined with various spikes, and as a whole formed this extremely useful biological tool that let it both feel its environment and grass prey, with those spines becoming inescapable traps when interlocked. And once within its clutches, the omnidons could then maneuver the victim into its waiting mouth, which, wait for it, was at the bottom of its body, and was full of large tooth plates, that formed columns of razor-sharp edges, just waiting to shred anything that entered. And let me tell you, no Cambrian animal was safe.

As for the time, it was an absolute giant, measuring 1.5 meters or 4.9 feet from tip to tip, allowing it to be the undisputed apex predator of its environment, which was primarily the warm coastal waters off of prehistoric China. For the time, the Omnodens was the real deal, you could say. But as far as this list goes, it is our smallest contender, as the animals would only get bigger and bigger from here on out. Even the very next period, the Ordovician, which began about 486 million years ago, produced predators quite a bit larger than anything seen during the Cambrian.

During this period, the Earth was very much still island forward, with much of the land being surrounded by the super-pandalisic ocean, which now stretched across half the globe. And in these waters, there was a new group that was ruling, which actually, since those days, have never gained as much power as they had back then. and that would be the cephalopods, the very same group that today have given us the likes of octopuses, or octopi, and squid. During the Ordovician, they were king, and their diversity was unparalleled, but not all of them were equally voracious, let's say, as some were tiny and pretty helpless, while then others evolved into highly efficient predators.

And amongst them all, the baddest of the bunch was arguably the endoceras, meaning inside horn. This creature would have been found throughout large parts of the world in its heyday, and was quite different. in the cephalpods we are familiar with now, not just because of its big size, but also because it had an outer cone-shaped shell that jutted out for a serious amount of distance. In this kind of cone was a hallmark trait of the order it belonged to, the endocerida, and likely played numerous roles in its life, offering buoyancy control, balance, protection, and of course an intimidating appearance. As thanks to its shape and then its actual body, an endoceros can measure up to 5.7 meters

or 18.8 feet. So, just as long as the giraffe is tall. And there's even some reports, albeit skeptical ones, that giant specimens were pushing much more than these measurements, potentially 9.1 meters or 30 feet, based off of a shell discovered in 1955. And mind you, that was just the shell. And at this size, these guys would have looked like some sort of moving tree. Only these trees were active and, uh, interested in eating others.

As we currently think the endoceros was a predator, armed with immensely powerful tentacles possibly secreted sticky adhesive substances that agripped a prey and allowed it to manipulate large animals. They also possessed a very sharp beak that would break down food before it would enter an inner ridula that was lined with tiny teeth. Unsurprisingly, because of its relatively large size, the endosarous would have been untouchable to pretty much all, and able to tackle most, if not all, their prey, as no other animal during its time was even close to its stature. Now it's believed to have stuck mainly to the sea floor where it feasted on other floor-dwelling animals, which back then consisted of trilobites, mollusks, brachio pods, and jawless fish.

Now one thing that did nerf it was that it did not have the best vision out of everything out there, based upon its pinhole-like eyes. So to get around this problem in the dim-lit waters, it's thought to have instead had an excellent sense of smell, like its living relative, the Nautilus, and thus used that in order to find food. So for now, there's no doubt it was the deadliest thing the Ordovician had to offer. But still, if you were swimming back then, you would likely be fine, likely. As despite its impressive length and being far larger than the Omnodens, the endoceros was kind of light,

as its shell was narrow and mostly hollow, resulting in a weight of about 100 kilos or 220 pounds. So while it was heavier than most humans, it likely would not have bothered trying to eat us. I would not test that hypothesis, though. But even if I did try, I still would much rather deal with one of these guys than what's coming up next. Because as the Ordovician ended, the world was plunged into a deep ice age, weakening the reign of the cephalopods and allowing a new group to rise during the following Silurian period. And that was the Euryptorids, commonly nicknamed sea scorpions. Like the Anomalacharis and Omnodens, these sea scorpions were in fact arthropods, only they were far more evolved and deadlier.

Fun fact, these guys had first appeared in the late Ordovician, and while they did make impressive progress, they were not the Earth's most dominant predatory group back then. But now is a very different story, and during the Silurian they maintained a worldwide range that extended from marine environments all the way to freshwater ones, while then both shallow and deep waters were both options too. Now, despite their nickname, Sea Scorpions were in fact not true scorpions, although in some ways they did look a lot like them, having similar, albeit supersized body shapes, frontal appendages that could feature pincers,

just like scorpions have today, and in some cases, a Europe to read could even have switched out their tail for a tailson that highly resembled a stinger, with some of the stingers being longer than knives, and I don't think I have to explain what they were likely used for, with the only silver lining here being that these stingers do not appear to have been venomous. And again, not all of them had stingers, and ultimately these guys were coming in every shape and size, given their vast amount of diversity. So naturally, some were more tame, and others more on the nightmare fuel side. But there is one in particular that it was just slightly more terrifying than the rest, and who I would call the king of sea scorpions. And that would be the giant galopterus. Found across Silurian Euramira, the Giacalopterus was an active and powerful predator

that seems to have been so fearsome than not even other sea scorpions seem to be safe. And frankly, there was no point trying to resist an attack from one of these guys. With the Giacalopterus being the largest sea scorpion that we know of, even when considering those outside of the Silurian, with some species of this genus measuring 2.6 meters or 8.5 feet from head to tail, which also means it's the largest arthropod to have ever lived. And for comparison, not even the tallest NBA player ever has it beat in length. Naturally, given this length and the fact that it was armored by layers of chitin, it was pretty hefty too, weighing over 200 kilos or 440 pounds,

with them weighing possibly even double this in giant specimens. And even in its lower end, good luck fighting this thing, as just like its body, its two frontal pincers were oversized too, with each being likely longer than your arm. Only instead of hands, the giant acylopterus had mega pincers, used to not only grip prey within iron. and vice, but also Terrence dripped them apart, as each were lined with sharp teeth-like structures that would have sunk straight through flesh. Like some living arthropods, they also had gnatha bases, which were modified sections of some of their limbs that were used to process food further by crushing and treading, so that it could then fit in their relatively tiny mouths. So, I know

what you might be thinking, which is that given its size, you might harbor the belief that you could have outpaced a gyclycolopterus, with it being essentially too slow to catch you. But that would be a very fatal belief, as its tail, so to speak, was so long and expanded that the tell sun itself is essentially modified into a rudder of swords, making it an excellent swimmer that had a high degree of maneuverability. And this might also been particularly useful for freshwater, as fossils do show that this guy was perhaps also a freshwater creature that was found in areas with lots of debris and tight areas. And if this is the case, it also means that the giant Galopterus is the first and only freshwater animal on our list. And while it is also the only sea scorpion to make the cut,

don't feel too bad for these guys, as they would continue to exist and thrive for hundreds of millions of years. So far we've had arthropods and cephalopods being the worst things the water could offer. But as the Silurian ended and the Devonian rolled in, a new animal joined the fray, who already existed, it was only now rising to the very top. And that would be fish. Yes, it was 419 million years ago when our ancestral lineage took the reign of thylacophobia, with this period even being dubbed the age of fish, as they underwent many ancient. evolutionary changes, lots of which made them a lot deadlier too. And amongst the array of fins, one group in particular that was making a lot of progress

were the placoderms, and now extinct class of fish, thankfully, who were distinctive for their armored plates, hence their name, which means plate skin. Like the sea scorpions, these fish were highly diverse, with some being bottom feeders, others herbivores, and of course there were also those that adapted a taste for flesh. And most notable amongst the meat lovers was undoubtedly a genus that you might have heard of, the Dunkley Austias. Now, this isn't just the first fish on the list, but also the first really famous animal, as like I said, I am sure many of you have heard of it, and perhaps you've also heard about its size

reduction over the years. And yes, unfortunately, the allegations are true. The dunkliosteus is not as big as we once believed. But don't be fooled into thinking the dunk has sunk. Get it? Because it's still the worst animal that a Vonian had to offer, and it would absolutely destroy any person underwater, which is thanks to a face that only a mother could love, as it was equipped with one oversized skull and jaw that opened wide enough for a person to literally swim through. And said swim would only end in a bloody mist, as their so-called teeth were even more gnarly than that. And I say so-called, as their teeth weren't really teeth. Instead, its jaws were literally giant self-sharpening plates made of solid bone that operated like a homemade guillotine,

slicing and chopping anything caught inside. And based on biomechanical models, avoiding this was almost impossible, as it could open and close its jaws with enough speed to form a powerful suction effect, meaning one moment you're swimming, then acts during two pieces. It also would not have helped if you were wearing any armor, despite armor also not being a thing that people wear while swimming. As the study found that the tips of these giant blades were coming down at about 7,495 newtons in force, which is, for perspective, over five times stronger than the bite of a jaguar, who is known to bite straight through skulls. Obviously, such a devastating weapon alone made this one fish you'd want to avoid. But it also certainly helped, or hurt, that it was a giant

for its time. And yes, again, it's no longer the 10-meter or 33-foot behemoth that we once thought it was, but it was still plenty big enough to kill, with the largest specimen suggesting a length of 4.1 meters or 13 feet, maybe even slightly longer than this. So, in other words, we are still talking about a predator the length of your typical male-grade white, and it was actually far heavier than them, too, with larger individuals clocking in at 1.7 tons, making it quite a bit heavier than a arc of the same length. And this mostly comes down to the dunk's body, being wider and more robust, but then it also had another thing weighing it down too, and that was an immense defense. The dunk was, as I said, a placoderm, meaning it was armored, and its armor was tough, being solid dermal bone

which covered its entire head in half of its trunk, with some of the plates being uber thick, like 25 times thicker than a knight's armor kind of thick, making the dunk not just the deadliest predator of the time, but also the hardest to kill. And given these features, it's no surprise that the dunk was able to expand through open waters within multiple regions of the planet, with fossils being known from the United States to Canada, Poland, Belgium, and Morocco. It would also end up dominating these waters for an extended amount of time, over 20 million years to be specific, all the way to the end of the Devonian in the beginning of the Carboniferous, 358 million years ago. However, as the Carboniferous started, the dunks'

rain ended. And while a fish would continue to be the deadliest animal in the ocean, it would no longer be a placoderm, as they had in fact gone extinct, with the new terrors in the water instead being primitive sharks. And just like how the Devonian is regarded as the age of fish, the Carboniferous, while generally being known for its swamps and insects, is also known as the Golden Age of Sharks, due to their immense diversity with there being at least 45 different families at the time. Now, each family was successful in their own right, but like always, only one was at the very tippity top, and that was Thugia Neodontida, a group that are now fully extinct, and were unlike any shark known today, possessing incredibly unusual jaws and dentition,

referred to as teethwurls. Many different kinds existed, and they had a global range at the time. And while each looked a bit off-putting, so you could say, the king of Carbonifer's Eugenioidants and the ocean in general was the one known as Adestis. Being an unusually large animal for the time, it could be up to 22 feet in length or 6.7 meters, and probably weighs similar to the largest great whites of today, making it unsurprisingly the biggest marine predator up until the Carboniferous. So, obviously, this is clearly one impressive feat, but what was really unique about it was

its tooth-wirl face, as I mentioned. As in the Indestis, it was pretty wild, which is saying something considering having a tooth whirl in general is already kind of weird. Specifically, both the upper and lower jaw only had a single row of large, serrated, and curved teeth that ran down the middle of the mouth and formed almost a giant scissors of sort, hence why it's been nicknamed the scissor-tooth shark. And when I say giant scissors, I really do mean giant, as we're talking about each side being longer than your torso. And so, given how strange this mouth was, there's of course a lot of interest

in just how it was used. And while there are many ideas, we're not 100% sure which is correct. The latest hypothesis suggests that the dust is actually implement what is essentially a two-gear system, thanks to a uniquely jointed bone that led it pull the bottom jaw towards the top on approaching prey, causing a simultaneous slicing and pulling effect. Sending the prey further down the mouth, will then also cutting it up more every second. The front teeth also seem to have evolved to grip prey. And while there has been the suggestion that it was an expert soft-bodied hunter, meaning it's specialized in hunting the rulers of old, i.e. cephalopods, and also perhaps

jellyfish, there has also been wear patterns found on a certain Edesta species, indicating that it fed on bigger game too, namely large armored fish. And that would align nicely considering that its calculated bite force was nearly 2,000 newtons. So a bit overkill for something soft. It also means that I, for one, am not going anywhere near this guy, which in turn means no beaches, unfortunately, as it was extensively found in tropical latitudes in very shallow marine waters, while also being known to inhabit estuarine habitats as well. So yeah, this primitive shark was truly the real deal, and it, or rather its family, were about to get more overpowered.

For when the Permian arrived, they remained large and in charge. And in fact, not only that, but they also produced a new genera that out the last of the last theododestis, if that's somehow possible, with the prime example of this being the parahecoprion. Now let it be known, I am not exaggerating when I say that this shark was the megalodon of the Paleozoic era, which by the way stretched from the Cambrian all the way to the Permian, as this thing was an absolute giant, dwarfing the vast majority of life during the Permian, be it on land or in the water, with some estimates putting it between 7 meters

or 26 feet and 13 meters or 43 feet long, which at the larger end makes it longer than any known shark alive today, bar the whale shark. And at this size, it's also feasible that the parahelicoprion was the largest animal to ever exist up until the following Triassic, with only its relative, the Helicoprian being somewhat comparable. But that's not even the craziest part, as there are those out there who think that Parahalicoprion was much larger than even these estimates, as one species, the peri helicopteron, Mario Suarezzi, seems to possess extremely giant teeth that outsized anything seen in its relatives,

leading to a few estimates of 100 feet in length or 30 meters. So yeah, we're going to need a bigger boat. Of course, though, this is a bit speculative, so you could say. As many people find this hypothesis a little bit hard to believe, considering that at this Titanic size, it would have had a very hard time feeding itself in a world where pretty much everything was levels below it in stature. But honestly, even at 13 meters or 43 feet,

it still is plenty inducing with classophobia already. Now, just like the Adestis, parahelicoprian was a fellow Eugenio Dantata, meaning that in conjunction to its giant size, it also had some pretty massive jaws, too, and weird ones, of course, at that. Only this time, instead of having scissor-like jaws, it possessed a literal buzzsaw for a mouth, as each individual came equipped with a giant tooth whirl positioned on their bottom mouth that was aligned with razor-sharp, flat, and serrated teeth, that formed a spiral about half the size of your body, while then the top of its mouth was composed

a tough cartilage, which would use to push these teeth against, causing catastrophic lacerations to normal prey, or just crush animals outright if they had hard shells or exoskeletons. Additionally, it should come as no surprise that, given the shape of its teeth, and its formidable size, it has often been suggested that the parahecoprion was the apex predator of its environment, an environment which seemed to be quite extensive, with its remains being known from both ends of the Pancheon continent. And based on the location of fossils, we assume that it was a pelagic shark, coasting shallow marine environments and hunting a large range of prey, including other sharks, fish, cephalopods, trilobites, and more.

But that said, even though the adults were pelagic, smaller individuals and juveniles might have frequently ventured into intertidal zones as well. So, really, your best bet to avoid this shark altogether is just to stay far away from any oceans and seas. And, uh, this advice is pretty much going to be the case going forward as well, as things are somehow only going to get worse and bigger. Yeah, if you thought para Helicoprione is big, just wait till the Triassic. Now, if you haven't heard, spoiler alert, but the end of the Permian was marked by the worst extinction

event of all time. And the waters of Earth were not spared by any means, with sharks being sent back millions of years in terms of diversity. So, it's going to be a bit until we hear from them again. But don't worry, because classophobia itself was doing just fine regardless, as during the Triassic, yet another new family had taken over, and this time, the first reptiles of the list. This episode is brought to you by Accenture. When your advertising operations fall out of sync, everything else follows. Spotify and Accenture are working together to reinvent the rhythm of ad sales, using automation, analytics, and smarter workflows to simplify campaign delivery and access better data across the business. The result? Less time spent on operations, more time

connecting brands with the moments and fandoms that matter most. Learn more at Accenture.com slash Spotify. Think theosaurs. First appearing in the early Triassic, this was a large order of marine reptiles that would go on to establish a massive dynasty, stretching all the way to the late Cretaceous. But it was the Triassic where their golden era started and ended. As in light of limited competition, this group spread across the world and diversified into many niches, including, of course, the apex predatory ones. Many ichthyosaurs looked a lot like dolphins, having shared a lot of similar traits due to convergent evolution. And while dolphins are surely successful creatures,

I wouldn't say they are all that terrifying. Ictheasors, on the other hand, were. at least a few of them, as they evolved into the metaphorical crackin of the oceans, and this resulted in a couple morphing into the world's largest hunters and animals of the entire period. In fact, there was even one of them, who was not only the apex predator of its time, but also possibly the largest reptilian predator to ever live, and that is the Ecteotitan. Known from only one species, the Severnensis, this giant of a hunter was first discovered in West England, and was immediately distinguished as being disgustingly big, somehow making even the parahelecoprion seem small, as the latest estimates based upon a located jawbone

suggests that individuals were nearly 25 meters or 82 feet long, which in other words is longer than a whole sperm whale. And because it had a big body construction, it was also extremely heavy, weighing between 35 to 80 tons, which of that weight is still on par with large whales, but there is a shot that it got even bigger. As one absurd specimen, dubbed the Ost specimen, might have been up to 35 meters or 115 feet long based off of certain models, which if was the case, would likely make it the largest aquatic animal of the entire Mesozoic. Whatever the case, though, the Ectheotitan was still a giant amongst giants, and it wasn't one of those big clunky types either, as the Ectheotitan had four massive fins, each several times longer than a human, while then it also flaunted a large tail

fluke, allowing it to swim scarily efficient for its large size. And it definitely needed this ability, since along with inhabiting archipelagos, it's also thought to have been common out in the open ocean, where it traversed large amounts of distance. And this was horrible news for all life at the time. As currently, the Ectheotitan is regarded as a Shastasaurid Ectheosaur, meaning it's part of a family of typically large genera that, for a long time, were thought to have been suction feeders. However, now, after studies on their jaw construction and locating teeth fragments, this is no longer thought to be the case, with the new idea being that they were truly killers. who relied on robust sectorial teeth to demolish things from mollusks all the way to other

megafaunal marine reptiles. And we know this as these quote-unquote food items have been found in their guts. And honestly, it seems the only thing that made in animals to the author menu was if they were larger than the ichthyosaur. In newsflash, that currently consists of nothing that we know of so far, and in other words suggesting that it was king and preyed upon pretty much everything else that came its way. Plus, since it was an ichthyosaur, that means it also also sported giant powerful eyes that gave it high visual acuity, and therefore the ability to scope prey in even the darkest of waters. So really, there was no point trying to hide from this kaiju.

Now the one caveat about the Icteotitan is that while we have found pieces of its jaws, we've yet to find actual teeth, so we aren't really sure if it did have teeth and if they did if they were sharp. It's simply a conclusion based off of its relatives, which does mean that technically there is a slight chance that this guy was not the deadliest animal around, at least from a predatory point. And while I am optimistic that we will one day find its actual teeth that would prove this hypothesis correct, if it for some reason was proved to be wrong, its replacement would still

just be another giant chastasaurid, likely the Shastasaurus himself, the namesake of the family. And if not it, then perhaps one of the ichthyosaurs that weren't as large, but had evolved to be macoraptorial, such as the Thelato Arcon, a 9 meter or 30 feet long Xthosaur to possess a long slender body, large skull, and robust teeth, that had two cutting edges. designed to tear through thick amounts of flesh, which is part of the reason why its name means ruler of the seas. And really, the moral of the story here is that the worst animal you could have swam into during the Triassic was going to be an Ictheasaur no matter what. But that said, while they might have had the Triassic on lockdown, Mother Nature doesn't really play favorites,

as at the end of the Triassic, the Earth, as its tradition, would be blindsided by an extinction event stemming from volcanic activities, which left the Ictheasors alive but hurt, and ultimately resulting the disappearance of the ultra-giant members, and therefore allowing a new group to sneak in. The Pleasosaurs. Just like the Ictheosaurs, Pleasiosaurus were marine reptiles too, yet they belonged to a different clade and were generally described as having big white bodies with four flippers and a relatively short tail, while then some had extremely long necks and others not so long. And those with the shorter necks actually tended to be a bit more toothy, as they belonged to a specific family known as the

the Pliasors, which evolved at the very end of the Tricac and spent very little time waiting to take over the oceans, experiencing a rapid ballooning in size and diversity during the early Jurassic, allowing them to soar all the way to the very top of the food chains. In general, Plyasaurus retained similar robust bodies and the Titanic flippers seen in their relatives, which helped propel them through the oceans and the seas of the power, but where they differed was that they had absurdly giant skulls

that were filled with some of the sharpest teeth of their time, allowing them to become extremely lethal killers in just about every big body of water on the planet. And through the years, there has been much debate on which Plysaur in particular was the deadliest, as there were just so many of them, sometimes dozens in a single environment. And it also seems they just kept getting bigger, with more remarkable specimens being found seemingly every few years. However, with this said, there is one genus that always seems to take part in the running, and may truly be the worst of them out there. And this was the famous Pliosaurus. first discovered in England, which, yes, is surprising I know, this pliosaur genus was always regarded

as an unusually large pliosaur. I mean, even before it was officially described, researchers who studied it were giving it various nicknames such as Predator X, simply due to the size of its jaw and bones. And though at one point in time it was regarded as a kaiju-sized animal, it has retained a large reputation, with some specimens suggesting lengths that exceeded 11 meters or 36 feet, while then weighing a whopping 11 tons, making it heavier than a killer whale. And then in 2023, a new study came out about a new specimen from the Kimmerich Clay formation that may have blown past these estimates, with a specimen potentially coming in at a staggering 14.4 meters or 47 feet long, which, for the record, is three times longer than a typical

Great Dwight. And not only is it beating it in length, the Plyosaurus has a bite that would put a great white to shame as well, as each one rocked a titanically oversized skull that was longer than your average NFL player. And these schools were not only extremely robust through bone alone, but they also had anchor points where giant muscles would have attached in real life, allowing for a devastating bite force of roughly 42,000 newtons, which is more than enough power to pulverize bone, especially when you consider the fact that the teeth doing the biting were knife-sized and trihedral. And that second word, trihedral, may sound a bit foreign to you, but it was a hallmarked trait to pliosaurus teeth. And what

meant was that their teeth interlocked at the sharp edges almost perfectly when the jaws clamped down, therefore turning its mouth into a giant continuous shear that allowed it to cleave through flesh and bone and diced giant megafauna's into itty, bitty pieces. And in fact, the bites of the pliosaurus were so deadly that unlike a crock that does a death roll or shark that bites and shakes, the pliosaurus likely killed by simply biting straight down. And well, that was it. 90-night. Astelauego. Sayonara. And armed with this weapon of mass prehistoric destruction, the pliosaurus became one of the most dominant animals of the entire Jurassic, be it water or even comparing on land, with numerous species evolving over time,

and it's spreading from the waters of Europe all the way to South America and being found in both shallow and deep environments, feeding on fish, cephalopods, sharks, marine reptiles, and even other pleasosaurs, where this diet often being described as generalistic. Which makes sense, because when you are as deadly as the pliosaurus, you don't really have any restrictions on what you can hunt. It also helped that the skin of the pliosaurus seem to at least in some parts, hydrodynamic, likely resembling the skin of leatherbacked turtles to help it swim faster, while then all its senses were also fairly well developed, including eyesight, smell and hearing, something which you don't often see in large predators, and again makes the

pliosaurus something of a complete package, which makes it all the more crazy that somehow worse things were still on the horizon. As in a repeating trend, it seems like not even the the Pliosaurs could retain their title past the Jurassic, with the Cretaceous bringing on a whole new wave of horrors, which was yes, thanks to again, yet another extinction event, which led to the appearance of likely the most famous animal so far on our list. And that would be, of course, the infamous Mosasaurus. This genus was just one of the numerous that made up the overarching Mosasaur group, and was actually one of the later iterations. Yet, unlike with the Pliosaurs, there is no doubt that the Mosasaurus, explicitly the Hoffmanian species, was among, if not the most, dominant. predator of the mall. It was one of the most successful species of mosesaur in general,

being found across numerous continents and spanning a reign of millions of years. And so, shocker, it was also one of the largest mosasores that we know of. Plus, again, being one of the biggest marine reptiles in general, with large matured individuals measuring up to 39 feet or 12 meters and weighing over 10 tons, possibly 12. Making this thing essentially a swimming T-rex. And based on isolated remains, it could have been even bigger. As one specimen produced a quadrate bone, that was about 150% larger than the average. And if this scales to body size, then it would be like finding a human fossil

that pointed to said fossil being in life as big as Robert Wadlow, who is, by the way, the tallest person that we know of to have ever lived. And so while we don't know exactly how big this monster specimen was, if I was somehow given the opportunity to see it in real life to verify its size, I'm going to pass on the opportunity.

And no matter what, it and most of the sores in general, were comfortably at the size where it was the bully, and I nothing was bullying it. It definitely helped as well that even for a large mosaeusore, this species was extremely robust, possessing a barrel-shaped chest and extensive cartilage throughout its body. Its goal then further matched its impressive nature, being heavily constructed, and showing signs that tendons and muscles in this area were very dense in life,

and therefore all pointing to one heck of a monstrous bite. In keeping in fashion, the teeth too were extremely robust, while still retaining a scary ability to slice through large animals, with each tooth having highly prismatic surfaces and two opposite cutting edges. And just in case you were concerned that they might hurt themselves with their own strength? Well, no need to fret, because the teeth, even though they were sharp, were built to endure high stresses too. So ultimately, if you did get bit by one, it would kind of be like being crushed and sliced at the same time. So lovely picture. To go along with the physical prowess, this guy had the bronze, but he also had the speed, as it had a long streamlined body, powerful tail and large flippers,

indicative of a fast and maneuverable predator, that was likely much faster than the plysaurus, despite being of similar weight. And unlikely use that speed, stage ambushes, where it would use its explosive energy and power to catch and decimate prey. And then taking a page from the Icthosaurus, this species also boasted large eye sockets, which indicated a possessed binocular vision and an excellent ability to process two-d environments, such as near-surface water areas. It was also just one mean son of a gun, too, as along with being an apex predator who fed on basically everything, it wasn't scared to tussle with its own kind either, with evidence of competition amongst mostsosaurs being widely known of.

And this includes, by the way, fighting with perhaps with the only, the other Mosasaur that might have it acclaimed the Cretaceous, deadly as sea predator, crown, the Tylosaurus. Existing at the same time, the Tylosaurus was yet another giant Mosasaur that it was similar but built a little more streamlined than the Hoffmani, and added an elongated Rostrum that formed a battering ram of swords, while then its teeth were also more conical and slender versus the Mosasaurus as well. And honestly, I think a fight between these two would kind of be a coin flip depending on who took the initiative, with the Tylosaurus winning if they get the jump, and the Mosasaurus winning if he got the jump. But ultimately, they'd together to get the jump.

The other held the sway of the late Cretaceous waters and were by far the most dominant marine animals that Cretaceous had to offer, both having worldwide presences and existing for millions of years, with them also each meeting the exact same end. And no, it wasn't competition from each other, but rather a giant asteroid that rudely interrupted the Cretaceous and destroyed, well, a lot of things. And this effectively ruined the streak marine reptiles have been on, because while the entire Mesozoic's top threats were reptiles, we have not had one since, with the next period, the Paleogene, being home to the very first mammal on this list. As mentioned, in light of the extinction event, the oceans and seas were left fairly void, allowing mammals to fill in the gaps, including those that evolved a whole lot of phlasophobia-inducing features. And while there were still sharks and predatory fish around, one animal that sticks out amongst the paleogene like a sore thumb is one of the scariest whales

to have ever lived, the bacillosaurus. Ironically, while it is a mammal, it does seem like mother nature wasn't just ready yet to leave the moses swathes behind, as this creature, which appeared 41 million years ago, looked a whole lot like a moussaur, possessing a long serpent-like body, large tail, similar frontal limbs, and a superficially similar-shaped jaw, giving it an uncanny appearance to Cretaceous as kings, so much so, in fact, that a first paleontologist did think that it was a reptile, with its actual name, meaning king lizard. But alas, like I said, this was no lizard, but rather a whale, which was also, by the way, likely the first super apex predator to arise after the dinosaurs. Found within the shallow warm waters that were abundant during the earlier and mid-Palaeogene,

this was the planet's undisputed top predator, and was a super giant compared to pretty much all other life around, with large males measuring some 20 meters or 66 feet in length, and weighing in excess of 15 metric tons, making it larger than both the mosasaurus and pliosaurus, and also frankly just complete anomalies for the time, as in general, not even whales as a whole had yet to reach the giantess we are familiar with today. And so you could definitely call it pioneer in whale size. But this wasn't the only aspect it was taking to the next level, as it was doing the same thing in the tooth department as well, having evolved the most complex teeth of any of the animals talked about so far, with each being double-rooted

and varying overall in the types of teeth, as bacillosaurus were known of canines, incisors, and serrated molars. And this differentiation, if you will, allowed it to do a lot of nasty things to its prey, including chewing them into smaller pieces before swallowing, something whales are actually not able to do any longer. The bacillosaurus teeth were also seemingly designed to withstand immense pressures when biting, and is believed that its bite force is on par with that of alligators and crocodiles. A useful trait surely, as a bacillosaurus pretty much specialized in tough large prey, which namely consisted of sharks, fish, and then even other whales, such as the Dordon, all of which have been discovered in the stomachs of these guys.

Now, interestingly, despite being a whale, this predator did not seem to have room in its head for melon, and no, not a watermelon or cantaloupe, but rather the structure often linked to a location in cetaceans. and as such we don't think it possessed echolocation capabilities. However, what it did instead possess was excellent directional hearing. So, even in the abyss, this guy knew where you were if you were making noise. And if you're in the abyss not dead, you probably are. And regardless, echolocation or not, it was clearly a successful animal, being very abundant in the tethous ocean, paratethysts sea, and the Atlantic Ocean,

where it would rule for millions of years. However, unlike the other beasts talked about so far, this guy would not make it to the end of the period, instead going extinct in the mid-eocene epoch of the Paleogene, due to a minor extinction event, and thus opening up the floor to contenders once more. And among said contenders fighting for the throne, there was a genus of shark known as the Ododos that would soon find itself winning a Game of Thrones. And while the Paleo gene was not yet its golden era, it would not have to wait long,

as when the next period began, the neogene, a new Ododotus species was ready to essentially rule the entire period, and do so in ultra-glory, not just bringing sharks back into the race, but also being the largest shark and maybe largest active predator of all time. The Megalodon. A name that needs no introduction. This species is too many, the peak of the Thelasophobia mountain. And when it was actually alive, I'm sure many animals would have agreed with this. And honestly, it's not hard to see why, seeing that sharks in general are pretty intimidating, so then just imagine one far larger than anything currently alive. And unlike many extinct animals, where we first find it, assume it's big and then

It gets smaller over time with more accuracy. This guy seems to just keep getting bigger and bigger and bigger. Kenchushimata, our researcher at Nepal University, is one of the people with the most knowledge on this creature, having started studying it over 20 years ago. And then his most recent studies, he estimated the giant Megs were able to hit 24 meters or 80 feet in length, and weigh between 80 and 104 tons,

so literally twice the size of a sperm whale. This was though the max estimate, and the average shark wasn't going to be that big. with some tooth remains suggesting average sizes closer to 10.5 meters or 34 feet in length. Well then the large average seemed to lay around 15 meters or 50 feet, so still plenty big. Just like modern great whites, it's too with the laminaform, but there has been much debate on if it looked like a great white or something completely different, and historically it was thought to be quite stocky and often reconstructed in a way that it made it look like an absurdly large great white,

more or less, but now we think it was actually significantly more elongated than before, It might have appeared quite different than once portrayed. And this newer body plan likely played a big role in its ability to be so large, as the longer, narrower body meant to lower drag and more efficient cruising, allowing it to be ready to go when the moment came to strike at its prey. And I certainly did not need much prep, as Megalons came with the ultimate finishers, and that would be Jaws from Hell. If you thought a great white's mouth was bad, then get a load of this guy,

as Megalodon could have jaws taller than any known human ever, and they were completely filled with about 276 teeth at any given time. with every single one of these teeth being no joke, ranging between three and 7.5 inches long, and being about as wide as your palm. They were also extremely robust in construction, triangular, and had fine serrations, making them the perfect weapons to cleave their massive chunks of flesh, or bone. And so with all this said, it probably comes as no surprise that it had a ridiculously powerful bite force, that was as high as 182,000 newtons,

which, for comparison, would kind of be like getting struck by an axe traveling over 110 miles per hour. but just with 276 giant teeth doing this all at once. So yeah, it caused massive catastrophic damage, no surprise. And we have literally seen this in prehistoric giant whales, which was a favorite snack of its, as certain recovered specimens aboard massive skeletal injuries coming from the meg. With some of these attacks even showing that megalodons evolved to simply kill large prey by tearing straight through their rib cage into their hearts and lungs.

But over time, it had seemed like the shark refined interpretation techniques depending on the prey, with some specimens showing it to mobilize their flippers and tails first, well then other prey items, namely reptorial whales, seems to have had their heads targeted first. And ultimately, like the others we've talked about so far, this giant predator was a generalist that ate pretty much anything it could. It'd be like the living Great White, in fact. Only, the Meg took things to a whole different level,

being obviously a far more powerful for predator, but then also being two times higher up in the food chain than a Great White, something which I didn't even know is possible. And really, only the Leviathan from the Neogene may have been a worthy rival, a fellow predator that wasn't a shark, but rather another large macaraptorial whale, being about 17.5 meters or 57 feet long, and came equipped with the largest biting teeth of any known animal ever, excluding tusks. And really, this guy was no pushover, as the Leviathan has thought have actually occupied the same trophic level as the Megalon,

thus making them competitors instead of insubordinate. But, unfortunately, no direct fossil evidence of interactions between the two have been found yet. But I think I know what I want for Christmas. Santa Claus, take note. But the truly scary, nay terrifying aspect about the megalodon was that it lived virtually everywhere. Fossils belonging to it have been found in every continent, bar Antarctica, and in almost every marine environment possible, in offshore deep waters, lagoons, the torres, and even coastal updwellings. So yeah, if you swam, you were screwed. Thankfully, though, we can all heave a sigh of relief, because the Megalodon never made it out of the neogene, and thus into the current period, as the one extinct about 3.58,

million years ago. But honestly, it's pretty freaking ominous to imagine that something like that lived so close to us. And if all the sea animals created so far, it makes a pretty darn good king, a king, though, that I'd very much like to stay buried. And with the Meg out of the way, we now arrive to the quaternary, the current period, which is still ongoing. So it's kind of unfair to say which animal is the deadliest or scariest just yet, but to be honest, I'd have a feeling that if we surveyed the sea creatures, humans would come up pretty close to the top of the list. Thanks for watching, and until next time, on Extinct Zoo.