Megalodon

Let’s go back in time: 3.6 million years ago. The ice caps on both of the poles are cooling and in the deep, dark depths of the ocean, some of the largest predators to ever exist are in trouble…

Otodus megalodon, the largest shark on record, is the stuff of Hollywood films. Analysing the fossilised teeth of these prehistoric beasts has led some experts to believe they could have been 18 meters long with the greatest bite force of any marine predator known throughout geological time. In fact, Otodus megalodon translates to “big tooth”, which isn’t surprising considering the length of an average megalodon tooth is about 10 centimeters.

Those cooling ice caps spelled trouble for Otodus megalodon – “megalodon” or “the Meg” for short – and within a few centuries, they’d all be extinct… or would they? Not everyone is convinced that these giant fish actually disappeared. More than 80% of the ocean is unexplored and some parts are so deep it’s almost impossible for humankind to know what’s there. That’s led some to believe the Meg might still exist in warm, subtropical oceans.

Investigating the mystery

Over the past few months, the Mysteries of Science podcast team have been speaking to experts, some of whom believe the Meg is very much a creature consigned to an era of time where giants roamed the world, but others believe there may be more to find.

So where do the rumors of a megalodon revival come from? A lot of the controversy surrounding the existence of the megalodon is due to a film originally aired in 2013 on the fact-based Discovery Channel called The Monster Shark Lives. Purported to be a documentary, it was quickly revealed that the film’s experts were actors, evidence was faked, and the story was entirely fictional. A clever marketing stunt for a series of programmes all about sharks, it’s rather unsurprising that the tale of the Meg took on a life of its own: who can resist the idea of such a mysterious creature?

What did the shark look like?

A close relative of the whale, basking, or sand tiger shark, these animals are known for their enormous size and “cosmopolitan distribution”, a term that means they would have lived the world over. Emma Bernard, curator of fossil fish at the Natural History Museum in London, told The Week Junior’s Science+Nature that the Meg would have looked like a modern day great white shark with a few different facial features; its rostrum (nose) would have been flatter and its jaw would have been more square.

Owing to the Meg’s size, catching agile creatures like sea lions who can turn quickly in the water would be very difficult. Brendan Malone, curator at Sea Life Manchester said the animal is likely to have feasted on large fish and mammals like dolphins and even sperm whales. Excavations have revealed megalodon teeth lying close to the chewed-up remains of whales and whale bones have even shown signs of shark bites.

A long route to extinction

With the polar caps cooling and basking grounds of those animals freezing, it’s likely to have led to a decline in the populations of animals Otodus megalodon would have eaten. Charles Darwin’s theory of evolution states that only the fittest animals survive and Malone thinks a combination of climate change and natural selection is what will have led to the extinction of the megalodon. An apex predator at the top of the food chain, its giant frame no longer supported by the ecosystem around it, and with cooling ice caps pushing nursing grounds further afield, it’s likely Otodus megalodon will have been starved out of existence.

Never coming back

We don’t know when the last megalodon is likely to have lived but experts say with a fair degree of confidence that it is unlikely the Meg will have survived that fateful ice age. However, it is true that some of its relatives did. So while tiger, whale, and great white sharks might frequently appear in textbooks, Otodus megalodon is firmly consigned to the history books.

Also

Otodus megalodon might be the largest known shark to ever exist but the blue whale is the largest known animal to ever exist. Records confirm a length of almost 30 meters (that’s double the size of a bus) with females being larger than males. There are several similarities between the giant beasts too, including the fact they can be found the world over.

Sadly, the blue whale nearly went the same way as the megalodon. The International Union for Conservation of Nature which aims to safeguard animals has classified the blue whale as endangered due to anthropogenic (caused by humans) threats. The only known natural threat to blue whales is the killer whale, which is actually a type of dolphin.

Human-created threats include climate change but also poaching, entanglement in fishing gear, and pollution. Human intervention is also likely to have saved them: the animals are now protected and their population has been gradually increasing in recent years.

First published in The Week Junior Science+Nature, issue 44, January 2022.