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Long before humans sailed the oceans, a real-life sea serpent ruled the waves.
So massive, it made the great white shark look like bait.
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Imagine a world ruled by sea monsters. A
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planet where the oceans belonged to
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titans. This wasn't a movie script. It
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was our Earth 82 million years ago. And
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the king of this underwater realm, the
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Moasosaurus.
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Let's dive deep into the story of the
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real life sea king. A creature far more
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fascinating than any film could capture.
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Our story begins not in the deep ocean,
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but in a chro quarry near the city of
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Mr. in the Netherlands. Around the year
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1764,
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workers carving out stone stumbled upon
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something extraordinary, a massive
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fossilized skull armed with a terrifying
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set of teeth. They had no idea what they
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had found. Was it a whale? a giant
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crocodile. The local army surgeon, a man
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named Jean Leonard Hoffman, acquired the
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skull, believing it was a relic from the
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great biblical flood. He was an avid
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fossil collector, and this was the prize
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of his collection. But this incredible
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discovery soon became the center of a
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dramatic dispute. The owner of the land
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where the skull was found, a cannon
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named Gording, sued Hoffman to get it
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back and won. Gording then proudly
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displayed the magnificent skull in his
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home, but its fame had spread when
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French revolutionary forces besieged
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Mustri in 1794.
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The French were so determined to capture
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this scientific treasure that a reward
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of 600 bottles of wine was offered for
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its safe delivery. The skull was
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eventually found hidden in God's cellar
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and seized. It was taken to Paris as war
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booty where it remains to this day. It
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was in Paris that the skull finally met
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the man who would unlock its secrets.
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The great naturalist George's Cuvia, he
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studied the jaws and teeth, comparing
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them to modern animals. In 1808, Cuia
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concluded it was not a fish, whale, or
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crocodile. It was a giant extinct marine
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lizard, a new kind of animal science had
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never seen before. He named it the
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fossil animal from MRI. Later in 1822,
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it was given its official name,
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Moscasaurus Hoffman, meaning lizard of
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the Muse River, in honor of Hoffman, who
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first recognized its importance. This
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discovery was revolutionary. It provided
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concrete proof of extinction, the idea
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that entire species could vanish from
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the earth, which was a radical concept
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at the time. The Mosasaurus wasn't just
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a monster. It was a bombshell that
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changed our understanding of life's
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history. So, who was this creature that
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caused such a stir? The Mosasaurus
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wasn't a dinosaur. It was part of a
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group of marine reptiles called
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Mosasaurs, which were actually closely
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related to modern-day monitor lizards
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and snakes. Think of a Komodo dragon,
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but super sized with flippers instead of
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legs and a powerful tail fin. They
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evolved from land dwelling lizards that
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returned to the sea, undergoing a
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remarkable transformation over millions
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of years. Their legs became paddles,
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their bodies became streamlined, and
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they developed a second row of teeth on
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the roof of their mouths called tergoid
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teeth, which helped them grip struggling
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prey and pull it down their throats. By
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the late Cretaceous period, from about
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82 to 66 million years ago, the
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Mosasaurus had achieved something
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incredible. global domination. They were
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the undisputed apex predators of the
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world's oceans. Their fossils have been
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discovered on every single continent
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from the plains of North America to the
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frozen wastess of Antarctica. This tells
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us they were incredibly adaptable,
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thriving in a wide range of marine
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environments, from warm, shallow seas to
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cooler, deeper waters. Now, let's talk
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about size. The movies love to depict
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the mosasaurus as a leviathan capable of
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swallowing a great white shark hole and
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leaping out of the water to snatch
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dinosaurs from the shore. While that
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makes for great cinema, the reality is a
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little different but no less impressive.
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The largest known species, Mosasaurus
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Hoffman, one from Mosri reached lengths
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of about 56 ft, all around 17 to 18 m.
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To put that in perspective, that's
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longer than a school bus and
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significantly longer than a
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Tyrannosaurus Rex. It was one of the
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largest marine predators of all time, a
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true giant of the deep. But it wasn't
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the only one. The Mosasaur family was
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incredibly diverse with over 40
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different genre ranging from smaller 3-
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foot long species to the colossal
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Mosasaurus itself. What did a 56- ft
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long sea lizard eat? The short answer is
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pretty much anything it wanted.
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Mosasaurus was a versatile and
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opportunistic hunter. Fossil evidence,
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including stomach contents and bite
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marks on other fossils, gives us a clear
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picture of their diet. They devoured
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large fish, sharks, and giant sea
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turtles, whose shells they could crush
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with their powerful jaws. They also
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prayed on ammonites, the large coiled
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shell relatives of modern squids. And
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yes, they were cannibals. We have found
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fossils of smaller mosasaurs with bite
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marks that perfectly match the teeth of
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larger mosasaurus individuals. In their
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world, it was eat or be eaten. Their
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hunting technique was likely one of
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ambush and brute force. They weren't
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necessarily the fastest swimmers over
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long distances, but they could generate
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incredible bursts of speed. Using their
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powerful fruit-like tail, they would
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launch themselves at prey with
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devastating force. Their skulls were
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also uniquely designed. Unlike most
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reptiles, they had a flexible
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doublehinged jaw, much like a snakes,
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which allowed them to open their mouths
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incredibly wide and swallow very large
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prey hole. They were the ultimate
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oceanic terror. For a long time, we
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thought of mosasaurs as purely marine
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animals confined to the world's oceans
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and saltwater seas. But science is
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always full of surprises. In a
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groundbreaking study published in
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January 2026,
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researchers announced a stunning
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discovery. They found evidence that
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Samosasaur species had actually adapted
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to live in freshwater environments.
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Fossils found in ancient river systems
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showed that these particular mosasaurs
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were thriving in rivers and estuaries
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hunting alongside giant freshwater
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crocodiles and other riverini predators.
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This completely changed our view of
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their ecology. It showed they were even
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more adaptable than we ever imagined.
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capable of conquering not just the seas
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but the rivers too. They truly were
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masters of the aquatic world. So if they
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were so successful, so dominant, so
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widespread, where did they all go? The
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reign of the sea kings ended not with a
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whimper, but with a bang, a
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catastrophic,
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world altering bang. 66 million years
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ago, a massive asteroid estimated to be
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6 mi wide slammed into the planet in
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what is now the Yucatan Peninsula in
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Mexico. The impact was cataclysmic. It
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triggered global earthquakes, volcanic
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eruptions, and mega tsunamis that swept
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across the continents. A thick cloud of
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dust and soot was thrown into the
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atmosphere, blocking out the sun for
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months, maybe even years. This event,
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known as the Cretaceous Spale gene
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extinction event, is famous for wiping
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out the non-avian dinosaurs. But its
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effect on the oceans was just as
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devastating. The lack of sunlight caused
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a total collapse of marine ecosystems.
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The phytoer plankton, the tiny organisms
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at the very base of the food chain, died
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off. This meant the small animals that
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fed on them like ammonites and small
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fish also starved and disappeared. For a
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massive apex predator like Mosasaurus,
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this was a death sentence. Their entire
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food source vanished from beneath them.
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You can't be a 56- ft long carnivore if
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there's nothing to eat. Within a
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geologic blink of an eye, the mighty
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Mosasaurs, who had ruled the oceans for
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millions of years, were gone. They
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vanished from the fossil record, never
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to return. The age of the great marine
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reptiles was over, paving the way for
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the rise of a new group of oceanic
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rulers, the mammals, which would
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eventually evolve into the whales and
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dolphins we know today. And what of the
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fossil that started it all? That famous
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skull, the one bought for 600 bottles of
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wine, remains a masterpiece of
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paleontological history. You can see it
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today at the National Museum of Natural
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History in Paris, a testament to a lost
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world. From its humble discovery in a
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Dutch quarry to its dramatic journey to
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Paris and its central role in changing
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science, the story of the Mosasaurus is
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a powerful reminder. It teaches us that
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our planet as history is filled with
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creatures more inspiring than any myth
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or legend. The most terrifying and most
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magnificent monsters aren't born from
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human imagination. They are born of
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time, tide, and the incredible,
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everchanging story of life on Earth.
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Thanks for joining us on this journey
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back in time. If you enjoyed this deep
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dive into the world of the Mercasaurus,
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don't forget to like, subscribe, and hit
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that notification bell so you don't miss
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our next adventure into the prehistoric
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world. See you next time.
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