what shark is big enough to swallow a man
As ane of the largest predators to have ever lived, megalodon captures people'southward imagination - and for good reason. Merely was this apex predator simply a beefed-upward corking white shark, and is it still lurking in the nighttime depths of the ocean?
Emma Bernard, who curates the Museum's fossil fish collection (including fossil sharks), helps divide fact from fiction.
The biggest shark in the globe
The earliest megalodon fossils (Otodus megalodon, previously known as Carcharodon or Carcharocles megalodon) date to 20 million years ago. For the next 13 million years the enormous shark dominated the oceans until condign extinct but 3.vi million years agone.
O. megalodon was not just the biggest shark in the world, but one of the largest fish ever to be. Estimates propose it grew to between 15 and 18 metres in length, three times longer than the largest recorded great white shark.
Without a consummate megalodon skeleton, these figures are based on the size of the animal's teeth, which tin can achieve 18 centimetres long. In fact, the give-and-take megalodon just means 'large tooth'. These teeth can tell us a lot, such as what these massive animals ate.
A megalodon tooth next to a molar of a great white shark
What did megalodon eat?
Emma explains, 'With its large serrated teeth megalodon would accept eaten meat - most likely whales and large fish, and probably other sharks. If you are that large you demand to consume a lot of nutrient, so big casualty is required.' This would have included animals equally modest as dolphins and as large as humpback whales.
We have other show of megalodon's feeding habits in the grade of fossilised whale basic. Some of these have been found with the cut marks of megalodon teeth etched in the surface. Others even include the tips of teeth broken off in the bone during a feeding frenzy that occurred millions of years ago.
Open wide
In order to tackle prey as large equally whales, megalodon had to exist able to open its mouth wide. It is estimated that its jaw would bridge two.vii by 3.iv metres broad, easily big plenty to eat two adult people side-past-side.
These jaws were lined with 276 teeth, and studies reconstructing the shark's bite force suggest that information technology may have been one of the nearly powerful predators ever to take existed.
Humans have been measured with a bite force of effectually 1,317 Newtons (Northward), while not bad white sharks have been predicted to be able to seize with teeth downward with a strength of 18,216N. Researchers have estimated that megalodon had a bite of between 108,514 and 182,201N.
The tip of a megalodon tooth is preserved in this fossil whale rib bone
What did megalodon wait like?
About reconstructions testify megalodon looking similar an enormous smashing white shark. This is at present believed to exist incorrect.
O. megalodon likely had a much shorter olfactory organ, or rostrum, when compared with the nifty white, with a flatter, almost squashed jaw. Like the bluish shark, information technology also had extra-long pectoral fins to support its weight and size.
'A lot of reconstructions have megalodon looking like a bigger version of the great white shark because for a long time people idea they were related,' explains Emma. 'We now know that this is non the case, and megalodon is actually from a unlike lineage of shark of which megalodon was the final fellow member.'
The oldest definitive antecedent of megalodon is a 55-million-year-old shark known as Otodus obliquus, which grew to effectually 10 metres in length. But the evolutionary history of this shark is thought to stretch dorsum to Cretalamna appendiculata, dating to 105 meg years old - making the lineage of megalodon over 100 1000000 years onetime.
'Equally nosotros've establish more and more fossils, we've realised that the ancestor to the slap-up white shark lived alongside megalodon. Some scientists think they might even have been in contest with each other,' says Emma.
Megalodon likely had long pectoral fins, similar modern blueish sharks exercise today © wildestanimal/Shutterstock
A cosmopolitan shark
O. megalodon was adapted to warm tropical and subtropical locations around the globe. The species was so widely spread that megalodon teeth have been found on every continent except Antarctica.
'We tin can find lots of their teeth off the due east coast of North America, forth the coasts and at the bottom of saltwater creeks and rivers of Due north Carolina, South Carolina and Florida,' explains Emma. This is likely due in function to the age of the rocks, simply likewise because they can hands be found on the bounding main floor allowing collectors to go diving for them.
'They are also quite common off the coast of Morocco and parts of Commonwealth of australia. They can fifty-fifty be found in the UK near Walton-on-the-Naze, Essex,' says Emma, although they are extremely rare in the Britain and tend to be of poor quality.
Why are megalodon teeth so common?
Almost all fossil remains of megalodon are teeth.
Sharks continually produce teeth throughout their unabridged lives. Depending on what they consume, sharks lose a set up of teeth every one to two weeks, getting through upward to 40,000 teeth in their lifetime. This means that shark teeth are continuously raining downwardly onto the bounding main floor, increasing the hazard that they will get fossilised.
Teeth are also the hardest function of a shark's skeleton. While our bones are coated in the mineral calcium phosphate, shark skeletons are made entirely from softer cartilage like our nose and ears.
Megalodon teeth take been found on every continent except Antarctica
So while the more than robust teeth become fossilised relatively easily, merely in very special circumstances volition soft tissue be preserved.
Fossilised megalodon vertebrae near the size of a dinner plate have also been plant.
'There is also a megalodon fossil found in Peru that patently has the braincase and all the teeth, with a pocket-size cord of vertebrae,' says Emma, 'although I have notwithstanding to come across high-quality images of this specimen.'
This extraordinary fossil may assistance create a better picture of what these gigantic predators looked like.
Extinction of a mega shark
Nosotros know that megalodon had become extinct by the end of the Pliocene (two.half dozen million years ago), when the planet entered a phase of global cooling. Precisely when the concluding megalodon died is not known, but new show suggests that information technology was at least 3.6 million years ago.
Scientists think that up to a third of all large marine animals, including 43% of turtles and 35% of sea birds, became extinct equally temperatures cooled and the number of organisms at the base of the food chain plummeted, resulting in a knock-on outcome to the predators at the top.
The cooling of the planet may take contributed to the extinction of the megalodon in a number of means.
As the adult sharks were dependent on tropical waters, the driblet in sea temperatures probable resulted in a meaning loss of habitat. It may also have resulted in the megalodon's prey either going extinct or adapting to the cooler waters and moving to where the sharks could not follow.
Great white sharks are largely misunderstood animals © wildestanimal/Shutterstock
Megalodon is also thought to accept given birth to its young close to the shore. These shallow coastal waters would have provided a nursery for the pups, protecting them from predators that were lurking in the open up water, similar the larger toothed whales. As water ice formed at the poles and the sea level dropped, these pupping grounds would have been destroyed.
But could megalodon still exist?
'No. Information technology's definitely not alive in the deep oceans, despite what the Discovery Channel has said in the past,' notes Emma.
'If an beast as big as megalodon still lived in the oceans nosotros would know well-nigh it.'
The sharks would leave telltale bite marks on other large marine animals, and their huge teeth would continue littering the sea floors in their tens of thousands. Not to mention that as a warm-water species, megalodon would non be able to survive in the cold waters of the deep, where it would have a meliorate risk of going unnoticed.
Source: https://www.nhm.ac.uk/discover/megalodon--the-truth-about-the-largest-shark-that-ever-lived.html
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