Megalodon a prehistoric scene 3D-illustration (Credit: iStock)
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Not sharks scary enough? The biggest of them all — the megalodon — is dead, three million years. And yes, if they were alive now, paleontologists would say — get out of the water, now!
Huge. Insatiable. Don’t stop.
There is no doubt that the megalodon was great.
No one is suggesting that the new action movie of The Meg– which burst to the top of the international box offices at the weekend – is even remotely scientifically accurate. It is a racing, pounding, frightening yarn.
But there are few things more fascinating than sharks.
As the largest and most powerful of them all, the megalodon has a special place in the nightmares of many. And because the smaller cousins still by the waters (if you call white hands are small), they seem so much more … real.
And that is the point.
There is actually an external reality, we can become a confused shark’s lunch. But a Predator his prey, or a Stranger’s nest? Not so much.
So sharks, even extinct, real fear, the power.
Carcharocles megalodon roamed the world coasts for a very long time. Evidence shows them that about as far back as 16 million years ago, and as recently as 2.6 million years ago.
And, yes: they had a very large teeth.
That is what megalodon means huge tooth).
The largest found so far measures approximately 18cm.
They are not really rare. Fossil examples have been found from all over the world.
“The teeth are often all over the world in marine deposits,” Flinders University Strategic Professor in Palaeontology John Long says, “but not so often to be on every site, they are easy to find.”
These teeth have the tendency to be scattered, and not in the context. This is exacerbated by those who for years a popular object for collectors over the last centuries.
“In all my years as a child the collection of fossil shark teeth in the Victorian sites (I had more than 500 copies), I have only ever found half of a large megalodon tooth,” Professor Long says.
Apart from these teeth and a few fossilized vertebrae, we don’t have much of an idea of what they looked like.
Almost every film, photo and model of a megalodon usually shows as just a scaled-up great white.
That’s not quite right.
Palaeontologists say that it more closely resembled a mako shark with a sleek, streamlined, even delicate lines.
And another common misconception is the size.
Fossil clues point to megalodons are up to 18 metres in the length, not the 25m or as often as is claimed. And even 18m is on the freak side.
Calculations of an average megalodon more than 14-million-year reign of terror come to approximately 10m. To put that in perspective: the largest great white ever recorded was 6.4 m.
Paleontologist and science communicator Dr. Paul Willis says that he can’t help but be skeptical about the megalodon’s size.
“The estimates are pretty hairy, because we have no complete skeletons of megalodon, usually just the teeth,” he says.
“A lot of that size estimates are based on the scaling of the teeth of living sharks. It is often so rough as ‘if the length of the living shark is 50 times the length of the largest teeth, and I have a fossil tooth that is 10cm long, then it must have come from a shark 500cm long.’ The reality is that an extinct shark known only from teeth could have been much larger (relatively small teeth) or much less (with a relatively large teeth).
“We will probably never know.”
Megalodon is often portrayed as aggressive rams are prey. It also has the tendency of cracks to large speed boats in two.
Yes, say palaeontologists.
Sharks sometimes physically crash into their prey. And there is fossil evidence megalodons used this tactic to stun their favorite meal — baleen whales.
And his jaws were the most powerful ever.
“The claws were as the gates of hell – 6ft high 4 ft wide (182cm x 121cm), lined with jagged teeth like steak knives, and is suitable for the cutting of meat of their prey with the greatest of ease,” Professor Long says.
Palaeontologists have modeled the bites of modern and ancient predators, ranging from the Tyrannosaurus rex and Liopleurodon by sabre-toothed tigers and Australia marsupial lions.
Pit them all against the megalodon, and they look puny.
His huge jaws to exert some 18,000 kg of force. No other animal, living or extinct, comes even close.
When it came to snack time, megalodon probably not interested in a lone surfer or swimmer. But a popular beach would be another matter.
“If there are a lot of people in an area, it can be a real bite!” Professor Long said.
You would think that megalodon would be safe at the top of the predatory tree.
It was. For a few million years.
“It is quite clear that megalodon was a top predator that fed off baleen — whale vertebrate have meg teeth still stuck in them, from the head-on attacks,” Professor Long says.
But, first, it had to grow and the age of that size. A juvenile megalodon might have been a simple fish feeder with more slender teeth.
But, about nine million years ago, the competition never got off the ground.
Livyatan had arrived.
An ancestor of the modern sperm whale, Livyatan not megalodon’s powerful bite. It was maybe a little larger. But her teeth definitely were.
At 30cm, this short ivory swords are the largest teeth ever found.
In the end, sharks as we know them — and pods of killer whales — also arrived on the scene. These were probably more effective to address the same prey. And a cooperative group of killer whales may have been able to on a lone-wolf megalodon if it is necessary.
Now, megalodon the successors are themselves in danger.
Another top-predator is killing sharks at the rate of 11,000 per hour.
THE ONE THAT GOT AWAY
Palaeontologists are quick to dismiss the prospect that the megalodon somehow managed to avoid extinction.
From their fossils, we have learned much about these ancient monsters of the deep.
What we know tells us that as they were in the area, we would know.
Some palaeontologists argue the evidence point to megalodons only live in warm, shallow waters. They simply weren’t designed to roam the open oceans, they say. They needed a constant supply of food, and their body and the skeleton was probably not strong enough for the pressures of deep water.
So, no: The Mb’s idea that megalaodons are hidden in deep undersea trenches just don’t fit. Instead, they were specialists on gorging on the fast food along ancient shores.
And that even if overweight tourists on the Beach Bondi beach may not prove tempting.
“If meg were there today, they are definitely — 100 percent — would have been found by now,” Professor Long says. “Their only source of food would be the large baleen whales. Through the centuries of whaling, they would have found and exploited as a rich source of oil (the liver) and cartilage (medicine). Like anything else valuable on this planet, we humans would have hunted them out, and so we would certainly have a historical record of them, and the specimens in our museum now.”
Then there is what they are known for their teeth.
Modern sharks shed up to 20,000 each during their life. Megalodons possibly much more.
Beachcombers would have found teeth now. And we are not talking about fossils.
Why megalodon went extinct is not known.
But there are a couple of ideas.
That is their main prey — baleen whales — were formed by 14 million years of being hunted. She was getting bigger. More difficult to surprise and take.
Professor Long says the ribs can also be just a new hide-out:
“Paleontology teaches us that even the largest, most fearsome creatures had their weaknesses, and eventually succumb to extinction,” he says. “Why megalodon became extinct is a very good question: their prey was going to areas that they could not, as the colder Antarctic waters. I think that baleen whales began to migrate to Antarctica to feed, and megalodon’s couldn’t live down there if it’s too cold.”
A recent study also shows megalodon may have been the victim of a previously unknown nautical mass-extinction event. About the time gone, the oceans have lost about 36 percent of their different forms of life. The change of the sea seems to have caused, the era of the shallow coastal waters to shrink, reducing megalodon’s hunting habitat drying.
UNDER THE MICROSCOPE
Mega shark discoveries are still being made. Earlier this month, the Museum of Victoria announced her palaeontologists had worked with a member of the public to discover some of the teeth from the prehistoric Carcharocles angustidens.
It is not a megalodon. It is a parent.
“I walked along the beach looking for fossils, turned around, and saw this shining glint in a boulder and saw a quarter of the tooth is exposed. I was immediately excited, it was just perfect and I knew that it is an important finding that needed to be shared with people,” said Philip Mullaly of his discovery on the Surf Coast of Victoria.
The 25-million-year-old tooth was 7cm long. The shark came out of it could grow to more than 9m, two times the size of modern great whites.
Just three grouped examples of Carcharocles angustid (Large Serrated Narrow Toothed Shark) are found.
Dr. Erich Fitzgerald, Senior Curator of Vertebrate Palaeontology at Museums Victoria, said he hoped there may still be more fossils are found in the rock at Jan Juc. So, in December and January, he led a team of palaeontologists and volunteers to dig out the boulder.
More than 40 teeth were recovered. But no fossilized bones were found.
Under the Carcharocles angustidens teeth were those of a other shark, the Sixgill (Hexanchus).
Museums Victoria palaeontologist Tim Ziegler said these teeth seem to have come from a number of individuals and were likely detached as they feasted on the huge skeleton.
“The teeth of the sixgill shark work as a crosscut saw, tore into the Carcharocles angustidens as lumberjacks felling a tree. The stench of blood and decaying flesh would have drawn scavengers from far around.
“Sixgill sharks are still living off the Victorian coast today, where they live on the remains of whales and other animals. This suggests that they have conducted that lifestyle for tens of millions of years.”
But not so Carcharocles angustidens. Nor Carcharocles megalodon.
“We palaeontologists know that we can never find everything that ever existed,” Professor Long says. “But it is unlikely to be something greater in the shark world than megalodon ever existed or at least we would have evidence about it — like a tooth or a giant scale or something. To be honest, nothing bigger than megalodon could have existed, because there was probably not enough food to support it. It is the same argument why lions are in the top of the food chain in Africa today.”
This story was previously published in the news.com.au.