We Were Wrong About Megalodon

0:01 Everything you think [music] you know about megalodon is wrong.

0:04 New 2025 research reveals it wasn't just a giant great white.

0:10 It was something far bigger.

0:13 For nearly 19 million years, this apex predator ruled the oceans.

0:18 The largest shark to ever exist.

0:22 Bigger even than a T-Rex.

0:24 With jaws so massive it could crush a whale in a single bite.

0:30 And then one day it just vanished,

0:34 leaving behind only teeth the size of your hands

0:38 and questions big enough to fill an ocean.

0:42 What happened to this nightmare of the deep?

0:45 Could it still be out there lurking?

0:48 Because more terrifying than the idea

0:50 of Megalodon surviving somewhere in the abyss,

0:53 is the possibility that we never truly understood it at all.

0:58 But new evidence is suggesting we were very, very wrong.

1:03 Could Megalodon not just have been faster, but far bigger than we thought?

1:10 I'm James Stewart, and you're watching Astram Earth.

1:13 Join me on this journey back to a time when Megalodon was at its peak.

1:17 We'll uncover the truth about this colossal predator and find

1:21 out how and why scientists got things so wrong.

1:27 Imagining our oceans patrolled by something three

1:34 times the size of a great white shark with jaws easily big enough to swallow

1:38 two people side by side is irresistible.

1:43 But is [music] it real?

1:45 To find out, we need to go back to a fateful day in 1666

1:51 when two fishermen caught a giant shark off the coast of Levono in Italy.

1:58 The locals were so shocked by their discovery that the Duke

2:01 at the time ordered that this curiosity be sent to Neil's Steinson,

2:06 better known as Stino, a Danish anatomist working in Florence.

2:11 Curiously, it wasn't the size of the shark that most interested Stino,

2:16 but rather its teeth.

2:18 He was struck by how much they resembled tongue stones,

2:22 triangular pieces of rock that since ancient times,

2:26 many thought to be petrified snake or dragon tongues.

2:31 Instead, Steno postulated that they were the remains of ancient sharks in rock.

2:38 He argued that rock layers formed slowly over time and that an object

2:43 like the teeth could give us a snapshot of a particular moment in history.

2:49 The significance of this observation would

2:51 change the course of paleontology forever.

2:55 He had discovered what fossils really were.

2:59 This was a revolutionary idea.

3:01 And whilst great for the future of paleontology, what's the link to megalodon?

3:07 Well, because sharks don't have bones,

3:09 their teeth are often the only part that survives, making them our best clues.

3:15 And Megalodon had a lot of teeth, 276 to be exact,

3:22 some of which were up to 18 [music] cm long.

3:25 Like modern sharks, Megalodon's teeth were being constantly replaced.

3:31 They were arranged so [music] that every time a tooth fell out,

3:34 one in the row behind would push forward.

3:37 One megalodon could get through 40,000 teeth in its lifetime.

3:42 In other words, over Megalodon's 19 million-year existence,

3:46 the sea floor became absolutely littered with old nashes.

3:51 And each one stood a chance of becoming a fossil.

3:54 And those fossilized teeth hold the key

3:56 to nearly everything we know about this enormous shark.

4:00 We even named it for them.

4:02 The word megalodon itself simply means big tooth.

4:05 So, in order to determine what Megalodon was, biologically speaking,

4:10 paleontologists have long tried to use these massive

4:13 teeth to [music] identify its closest living relatives.

4:16 Megalodon was first formally described in 1835 by Swissborn American naturist,

4:23 geologist, and teacher Louie Agassiz, who named the species Cararadon Megalodon.

4:30 It was placed here in the genus of sharks

4:33 within the lamniday family almost entirely because its

4:36 large triangular serrated teeth were pretty similar

4:40 to that of modern-day great whites known as carcarodon carcarius.

4:46 A skeletal reconstruction led by Mike Godfrieded in 1996 backed this up.

4:52 He gave Megalodon the look of the stockier

4:54 [music] great white we know and fear today.

4:58 extrapolating megalodon size from the dimensions of its teeth.

5:03 Which is all pretty handy, isn't it?

5:04 Case closed.

5:05 Giant great white shark incoming.

5:07 Jason Staithm's delighted and the Megres wres havoc in Hollywood.

5:12 Well, not quite.

5:16 In the early 2000s, distinct differences between the teeth and a closer

5:21 look at the fossil record suggested something a bit more complicated.

5:27 So during the mid 2000s, Kevin Nyberg and his colleagues conducted a series

5:32 of morphometric analysis between megalodon and great white sharks.

5:37 They found no overlap in shape variants of the teeth,

5:41 nor in the shape of their roots.

5:44 In simple terms, the serrations of white

5:46 shark teeth were irregular and triangular,

5:49 whereas those of megalodon were finer and rounder.

5:53 Essentially, it seemed very unlikely that the great white

5:57 evolved from Megalodon as originally thought, but something else.

6:03 In 2019, Donna J.

6:06 used this new evidence to officially allocate

6:08 megalodon [music] within the extinct Otodontday family,

6:12 aka the megatthed sharks.

6:15 Other sharks in this family include

6:17 Ottous obliquequis megalodon's earliest ancestor that lived

6:22 during the eosene times about 60 to 37 12 million years ago.

6:28 So today we arrive at the middle ground

6:30 of ootus megalodon the [music] scientific name megalodon now generally

6:35 goes by although it should be noted not everyone

6:38 agrees with this and some still prefer to use cararacles.

6:42 There's a bit more dental drama in amongst all of that to [music] be honest.

6:46 But I think that gives us a good overview of Megalodon's lineage.

6:50 But that's not the only thing scientists were mistaken about though.

6:54 And something even more sinister was about to come to [music] light.

6:59 Every depiction of this prehistoric shark you've seen in theaters,

7:03 online, and in your nightmares is very likely wrong.

7:09 Because the largest shark to have ever

7:11 lived was actually bigger than we first thought.

7:15 Much bigger.

7:17 For a long time, the estimates for how long Megalodon was were based

7:21 purely on lots of fossilized teeth

7:24 and the occasional very rare fossilized vertebrae.

7:28 No complete skeleton has ever been found.

7:31 Now, from that evidence we had,

7:33 we thought its body was between about 15 and 18 m in length at most until now.

7:41 Because this year in 2025,

7:43 a group of 28 international scientists led by paleobiologist Dr.

7:49 Kenshu Shimada reshaped how the world thinks about this prehistoric giant.

7:56 Central to this reimagining is one particularly

7:59 rare set of vertebrae discovered in Belgium

8:03 and now safely cataloged in the Royal

8:05 Belgian Institute of Natural Sciences Conservatories in Brussels.

8:10 It measures a whopping 11 m in length,

8:14 but that only represents the trunk of the shark.

8:17 Its head and tail are still missing.

8:21 So to try and fill in the gaps, Shimada's team compared it to the bodies

8:25 of 165 other living and extinct shark species.

8:30 This enabled them to extrapolate the animal's true size,

8:33 and they found that Megalodon's head likely made up about 16.6% of it,

8:38 while its tail accounted for around 32.6%.

8:43 Applying this to the Belgian vertebrae specimen,

8:46 the shark's total length would have been roughly 16.4 4

8:50 m with a 1.8 m head and a 3.6 m tail,

8:55 which was pretty much in line with what the current estimates were.

9:00 But here's where things get really interesting because there's

9:04 another even larger fossilized vertebrae from Denmark, 23 cm wide.

9:11 Now, that suggests that some individuals may have

9:14 been even larger than that 16.4 4 m.

9:18 Perhaps even reaching an astonishing 24.3 m,

9:24 nearly 10 m larger than we previously thought,

9:28 rivaling the size of a blue whale and weighing in at a mindblowing 94 tons.

9:35 But the revelations don't stop there.

9:38 Not only were megalodons bigger than we previously thought,

9:42 they also looked vastly different, too.

9:47 Whilst reviewing a paper from August 2022 in which

9:51 scientists built a digital 3D model of Megalodon,

9:54 Shimada and his team realized that some of the maths

9:57 behind the sharks proportions didn't seem to add up.

10:01 Using the same 145 species of living sharks and 20 ext,

10:07 they built a database logging the proportions of their heads, bodies, and tails.

10:12 The researchers then compared them to the parts

10:14 of Megalodon's body that have been found,

10:17 and what they found changed everything.

10:20 Megalodon was not a stout tankike great white shark at all,

10:26 but rather a more streamlined fish with a much

10:29 shorter nose when compared with the great white.

10:33 It had a flatter, almost squashed jaw equipped with extra-l

10:37 long pectoral fins to support its weight and size.

10:41 It was more like a lemon shock.

10:44 The same study also revealed something deeply disturbing.

10:48 Fossilized vertebrae suggested that baby megalodons were born huge,

10:52 measuring between 3.6 and 3.9 m long.

10:56 But that's not the gross part because like modern-day great whites,

11:00 they also likely practiced a form of inutro cannibalism

11:05 where embryos ate unfertilized eggs to fuel their early development.

11:11 Survival of the fit is personified.

11:16 We've seen what happens when we lose large predators.

11:19 The damage to ocean ecosystems is catastrophic.

11:23 And sadly, human activity today doesn't help

11:26 that with things like over fishing and bottom trolling.

11:29 But that's where our friends at Planet Wild come in.

11:32 They're a community-based nature protection organization fighting back.

11:37 Think of them like crowdfunding, but for nature.

11:40 Each month, their community funds a project

11:42 to restore nature around the world and then

11:44 documents it with a YouTube video report so

11:47 you can see the impact of your contribution.

11:50 It's actually their transparency that inspired us

11:52 to become members in the first place.

11:54 They had this amazing project recently where

11:55 an underwater sculpture museum had been created

11:59 to help combat bottom trolling in the Mediterranean

12:02 and of course restore the surrounding ocean.

12:04 And there's loads more projects just like that.

12:07 Actually, I'm so passionate about what they do,

12:10 I'm going to put my money where my mouth is here.

12:13 The first 100 people to sign up to Planet Wild using

12:17 my code Astramm 12 will get their first month paid for by me.

12:23 Yep, just scan the QR code on the screen

12:25 right now or click the link in the video description.

12:27 And the best part, you'll immediately have an impact

12:30 and see the results in less than 30 days.

12:33 As we head back to the video,

12:36 all of those revelations about Megalodon's shape also led

12:40 to Shimada's team stumbling upon a larger pattern in marine biology.

12:45 This new, more streamline,

12:47 more menacing shape makes sense as to why Megalodon was able

12:52 to grow to the whopping 24.3 [music] m his team had estimated.

12:58 Stocky bodies like that of the previous

13:00 iterations of megalodon create far more drag,

13:03 making it much harder to move efficiently through the water.

13:06 These constraints are why our current modern-day great white

13:10 sharks tend to cap out at around 7 m.

13:13 Any bigger and they would lose

13:14 the speed that makes them such dominant predators.

13:18 The same logic applies to other animals such as blue whales.

13:21 They can grow up to 30 meters long, owing to their sleeker,

13:25 more hydrodnamic shape,

13:26 [music] allowing them to traverse hundreds of thousands of miles of ocean.

13:31 Megalodon's new lightweight frame may also go some way to explain

13:36 why it was able to pop up all around the globe, too.

13:40 The species was so widespread that megalodon teeth

13:43 have been found on every continent except [music] Antarctica.

13:49 Based on what we've just discussed,

13:50 it seems very much like Megalodon was superior

13:53 to the great white shark in every single way.

13:56 Not only unrelated, but more refined, fitter, bigger, better.

14:02 It makes the fearsome great whites we have today feel pretty feeble.

14:07 But don't write off the great white shark just yet,

14:10 because it has one last card up its sleeve.

14:14 One that's about to deal a fatal blow.

14:19 So, now we finally know what this creature was.

14:22 How did something so dominant, so powerful, just disappear?

14:27 What went wrong for Megalodon?

14:29 How did the ocean's most fearsome predator just vanish from history?

14:35 We know when Megalodon went extinct because we've only ever found

14:38 teeth that are roughly between 20 million and 3.6 million years old.

14:44 But why Megalodon went extinct is not as straightforward.

14:49 It had [music] spent millions of years flourishing

14:51 in the nutrient-rich waters of the Meioene epoch,

14:54 and it certainly had a good run.

14:57 But all good things come to an end.

15:00 One theory that has popped up time and time again

15:03 is that as the planet got closer to the ice age,

15:06 it brought about colder water temperatures and it simply

15:08 became too cold for the giant shark to cope.

15:12 However, data from scientists Catalina Pimeento and Hberto G.

15:17 Feron seem to suggest otherwise.

15:20 When analyzing Megalodon's global distribution through time,

15:23 Pimento found that Megalodon was capable

15:26 of inhabiting colder latitudes and its distribution through

15:30 time did not correlate with any warming

15:32 or cooling temperature trends we know of.

15:35 These findings fit nicely into the work of Ference,

15:38 who has theorized that Megalodon was likely a mistherm,

15:42 a type of warm-blooded animal that keeps

15:44 its body temperature somewhat warmer than the surrounding

15:47 water and therefore able to cope quite well with a wide range of temperatures.

15:53 So, if the planet itself couldn't see Megalodon off, then what did?

16:01 Pimeento's research showed that Megalodon's global

16:04 abundance and distribution peaked in the middle

16:06 meioene roughly 11.6 to 16 million years ago before going into [music] decline.

16:13 Now, interestingly, this correlates with a huge loss of whales,

16:17 dolphins, and porpuses, i.e.

16:19 megalodon's favorite foods.

16:22 Extinction [music] rates of marine megapora,

16:24 the largest genus or species of a particular group of animals,

16:28 were incredibly high in the pioene.

16:31 Among those lost included 55% of large marine mammals, 43% of sea turtles,

16:38 and 9% of sharks with a total

16:41 of 36% of large marine species [music] going extinct.

16:47 Changes in sea level may have also impacted megalodon indirectly.

16:51 Fluctuations were common during the plyio [music]

16:53 scene and could have spelt bad news for a giant shark if coastal habitats where

16:58 there's a lot of food available were impacted.

17:01 As all of that occurred, Megalodon was likely forced to compete harder

17:05 for what remained [music] with guess who?

17:09 Jaws himself, the great white shark.

17:13 After all that, Megalodon's size could well have been its undoing.

17:18 The evolution of the great white,

17:20 [music] a smaller creature that needed less to eat,

17:23 meant megalodon never really stood a chance,

17:26 a deep sea version of David versus [music] Goliath.

17:30 So, how is it that 3.6 million years after it went extinct,

17:34 there are numerous eyewitness accounts

17:36 and documentaries suggesting it's still out there?

17:40 Could Megalodon really be seeking refuge in the dark depths of the ocean?

17:45 Is it possible even that it's hiding in the Mariana Trench,

17:48 waiting for the perfect time to reveal itself to the [music] world again?

17:53 Well, for a brief moment, they almost had us.

17:56 One of the best known fuelers of the Megalodon Alive Fire was a 2013

18:01 documentary which revolved around an investigation

18:04 into the huge shark's continued [music] existence.

18:08 Watched by millions, it was, I must admit, quite compelling.

18:12 It showed a blue whale carcass beed off the coast

18:15 of Hawaii that looked to have been brutally attacked.

18:19 A scientist in the program explained that the culprit

18:22 had to be the size of a megalodon.

18:25 And other scenes claim to show 6-ft tall fins

18:28 poking out of the ocean near similar blue whale attacks.

18:33 Unfortunately, or fortunately, depending on your view,

18:36 many people missed the disclaimer at the start of the show,

18:39 which [music] stated the potential return of the species was not based on fact.

18:45 As it transpired, the entire documentary was full of faked photos,

18:49 [music] footage, and even actors hired to portray scientists.

18:54 There have, of course, been other unconfirmed sightings of living megalodons.

18:59 In 1918, a fisherman off the eastern coast of Australia claimed [music] to have

19:04 seen a shark 31 to 95 meters long making off with some lobster pots.

19:10 And as recently [music] as 2022, NBC Boston led with the headline,

19:16 "Two megalodon sightings off New England." [music] Spoiler alert,

19:20 it was a basking shark.

19:22 Another common argument for megalodon being out

19:25 there somewhere points to the fact that some

19:27 large animals such as the giant squid took

19:30 [music] a while to be discovered by scientists.

19:33 However, their remains have been washing up on shore

19:36 and caught by fishermen for decades if not longer,

19:39 giving us real hard evidence that [music] they existed

19:42 before we had ever seen or recorded a full specimen.

19:46 By far and away the most common argument you'll see

19:49 for megalodon survival is we've only explored [music] 5% of the oceans.

19:53 Whilst that may be true thanks to science,

19:56 we don't really need to explore all that much

19:58 to know that a giant whale killing shark isn't in there.

20:03 Megalodon was an apex predator and if they were still out there,

20:07 orcas and great white sharks would never have taken up their mantle.

20:12 It's also no coincidence that from around the same time megalodon went extinct,

20:17 the size of whales exploded.

20:21 In the absence of large predators like megalodon,

20:24 whales in the plea scene were twice the size of those in the plyene.

20:28 [music] Hence the appearance of the blue whale.

20:31 But I've saved the best theory for last.

20:33 Don't you worry, I hadn't forgotten.

20:34 What if the megalodon is just hiding in the Mariana Trench?

20:38 Love this.

20:39 A theory popularized of course by Jason Staithm's film The Meg.

20:43 That story was actually based on the fact

20:45 that Megalodon teeth were discovered near the trench

20:47 by the HMS Challenger in 1873 and were

20:51 considered new because they were unusually white,

20:54 [music] dated to between 24,000 and 11,000 years old.

20:59 The reality though is much different.

21:02 Instead, it's likely the fresh pearly

21:05 whites were just uniquely [music] well preserved

21:07 by a thick mineral crust of manganese

21:10 dioxide that significantly reduced the decomposition rate.

21:14 Megalodon teeth absolutely recent.

21:18 No way.

21:21 There are other issues, too.

21:22 If we've learned nothing else from this video,

21:24 it's that Megalodon likes to eat and eat a lot.

21:28 We made a video on the Mariana Trench.

21:29 Please do check it out on the channel.

21:31 and we showed exactly what is there.

21:34 And the reality is there's not loads.

21:37 Certainly not enough food to sufficiently feed a 24 m mega shark.

21:42 Incidentally, snail fishes are the deepest dwelling fishes,

21:46 but we don't find them until much deeper than 8,000 m.

21:50 Quite possibly for the same reason.

21:52 They're just isn't enough to eat, and they're only 20 cm [music] long.

21:58 So, there we have it.

21:59 Our journey back in time to the true land of the giants and one

22:03 of the most gloriously monstrous beings ever

22:06 to exist comes to an almost anticlimactic end.

22:11 Something so mysterious and so powerful feels like

22:15 it deserves to bow out amongst fireworks and explosions.

22:19 But instead, the reality is rather meek.

22:22 Despite that, it doesn't make the megalodon any less intriguing.

22:26 It seems fitting that something so elusive

22:28 was able to keep a 19 millionyear-old secret.

22:31 And that leaves me feeling [music] very satisfied indeed.

22:34 Actually, yes, Megalodon is most definitely extinct.

22:38 But it's mystery still lives on.

22:40 There's just one way to know for certain what Megalodon was.

22:45 And like any good murder mystery cliffhanger, they've still never found a body.

22:50 So until then, giant lemon shark it is.

22:55 Let me know you've got this far in the video by leaving

22:57 a lemon emoji in the comments as a tribute to Megalodon's lemon shark makeover.

23:03 And I'll see you in the next one.