Palaeontology: The Mighty Megalodon

23-million-years ago to just over 3-million-years ago, the apex predator of the seas was the hulking cousin to today's Great White Shark. That big beastie was Otodus megalodon — the largest shark to ever swim our seas and the largest fish as well.

This big boy swam in at a whopping fifty-tonnes and grew to 18 metres in length — twice the size of an ankylosaur or triceratops and larger than a Tyrannosaurs rex but a wee bit smaller than a brontosaurus.

From our modern oceans and their modern cousins, that is a full three times larger Deep Blue, the 2.5 tonne, 6-metre long shark found off Oahu's south shore in 2019. Deep Blue weighed the equivalent of two Stonehenge Sarsen stones or half a house. Picture your house, now add another half and that is the size of Otodus megalodon. It truly puts their size in perspective.

We often estimate the size of animals and what they ate by the size and shape of their teeth. Megalodon had large serrated teeth up to 18 centimetres long — perfect for dining on dolphins and humpback whales — and they had loads of them. Their mouths were lined with up to 276 teeth and these packed a punch with one of the most powerful bites on record. We have a rather paltry bite force of around 1,317 Newtons (N) when we chomp down with gusto.

In 2012, we learned that the most powerful bite recorded from a living animal belongs to the saltwater crocodile. Gregory Erickson of Florida State University in Tallahassee compared 23 crocodilian species and discovered that the largest saltwater crocodiles can bite with an impressive 16,414N. That is more than 3.5 times the crushing force of the previous record-holder, the spotted hyena. Still, our aquatic friends beat that, if only slightly. A great white shark does indeed have a mightier bite than a crocodile.

We have known the estimated bite force of a great white a while longer. In 2008, Stephen Wroe of the University of New England in Australia and his colleagues used computer simulations to estimate the chomping pressure of a great white. Not surprisingly, great white sharks chomp in at an impressive 18,216N — greater than a saltwater crocodile but a full ten times less than Otodus.

But all those bites pale in comparison to Otodus megalodon — this beastie takes the cake — or the whale — with a bite force of 182,201N.

It is amazing to think of something as large and majestic as a whale being on any creatures menu but feast they did. Megalodon could open their toothy jaws 3.4 metres wide — that is wide enough to make a meal of a whale or swallow you and a friend whole. I added a brave — or very foolish — scuba diver to an image I will post on the ARCHEA blog to give you a sense of scale.

Otodus megalodon was a bit blunt-nosed in comparison to a great white. They hail from a different lineage that broke off deeper in their hereditary history around 55-million-years ago. We now know that Otodus megalodon was the last of their lineage and the great grandbaby of Otodus obliquus and possibly Cretalamina appendiculata, who cruised our ancient seas 105 million years ago.