The largest shark who ever lived.
This leviathan struck terror in the hearts of mammals for millions of years.
Its demise was as abrupt and left a huge niche in ocean ecosystems.
Could a new beast assume the role of giant killer?
This is the Megalodon.
Hi I’m Talia Lowi-Merri and you’re watching Paleologic. Megalodon is one
of the most fearsome predators of all time. If you think a great white shark is scary,
this submarine carnivore will give you nightmares.
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Megalodon was massive, big enough to eat whales.
Some estimates put them at around 18m,
though there’s some debate about that because all we have left of them is their teeth.
Like all sharks, megalodon’s skeleton was made of cartilage,which doesn’t fossilize.
Luckily, their teeth were made of calcium phosphate materials, which do fossilize,
so we have plenty of huge teeth to get an idea of megalodon’s monstrous size.
Their teeth are the largest of any shark ever found.
And they’re really, really, realllllyyyy big.
A mature great white shark’s teeth are up to 7 cm.
Megalodon’s larger known teeth are over 20 cm long.
Just a look at how tiny great white’s teeth look next to them.
Megalodon made the great white shark seem like the meh white shark. And it did for a long, long time.
Megalodon appear in the fossil record around 20 million years ago, a new time for earth
where grasslands and kelp forests had just developed and new species were thriving.
From then, they got gradually larger,
reaching their maximum size right before extinction, around 3 million years ago ago.
During their reign there was no safe haven in the ocean, especially if you were fat and delicious.
Megalodon, like their extant cousins, ate fatty marine mammals,
which to be fair, weren’t as massive as they are now.
We Know of this shark’s cetacean diet because we have found whale bones with
shark tooth marks that could only have been made by a Megalodon.
One of those mammalian snacks was piscobalaena which was about 5 meters long.
Not nearly as large as modern whales baleen whales but just slightly smaller than orcas.
That’s still nothing to scoff at. Killing something that
big required gigantic jaws and a powerful bite.
Their mouth could be up to 3 m wide, enough to eat you and a puma whole at the same time.
Not that they would have liked you, you’re probably too bony
compared to their favourite snacks. Their killing strategy seemed to have
been ambushing whales from below and biting off a big chunk of their guts.
Whales would die before they even knew what bit them.
With a body made for killing giants,
baby megalodons were under a lot of pressure to grow quickly.
Studies done at the fossil sites of megalodon nurseries show that they were born at about 2 m
of length, about the size of a sea lion, and could reach their full size at just 25 years of age.
It’s unclear what they ate in their youth, but like in most shark species,
the competition was likely intense and few would reach their full size.
Cannibalism is relatively common in sharks and for portions of their life,
their siblings would have been the most available source of food.
Its a dangerous business being a shark, and unfortunately for this species,
their chapter in the book of life came to an end pretty abruptly.
For such a formidable hunter to go extinct, it probably took
massive changes in their environment. Changes in ocean currents caused by
shifts in the tectonic plates caused major changes in the water temperatures.
This likely caused krill to become less abundant
in tropical waters. Several whale species went extinct
and many of those who survived moved to areas with better food supply such as colder polar waters.
Megalodon likely couldn’t survive, or at least breed, in those areas.
So with not enough whales in the tropics, and a huge body requiring lots of energy,
megalodon starved to oblivion.
This was the best day ever for cetaceans and they raved on for millions of years
until humans got involved and spoiled the party.
But in just those couple million years without megalodons whale populations exploded.
New species appeared including the amazingly huge blue whale.
Without a whale-eating apex predator there was little pressure to be nimble and their
bodies essentially become factories to turn tiny crustaceans into blubber reservoirs.
But this wasn’t truly the end to megalodon’s place in the human psyche.
Their amazing biology has fascinated people
for as long as their teeth have been discovered by beach goers.
Naturalists and scientists have been studying their teeth since at least the 1600s.
Of course, at the time most people assumed the teeth belonged to dragons or monsters.
But the similarity to great white teeth was quickly pointed out
and the myth of a living giant shark was born.
The name megalodon was coined back in 1843, and from those early teeth
analysis everyone could tell they were like nothing we’ve ever seen before or since.
Their teeth are still
being found and sold on the internet, so if you could own a piece of shark history too.
Though the larger teeth go for thousands of dollars, so maybe not the savviest investment.
And yet many people wonder if there could still be any megalodon alive in the depths of the oceans.
But don’t worry, something so big would have been spotted by now. They would have
to come closer to the surface to look for whales. (show peaceful footage of the ocean)
The ocean is a peaceful place where you can go and
relax and enjoy the beauty of the natural… *screams*
So what should we talk about next, please let us know in the comments
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Thanks for coming along on this journey through time, I'll see you later.