Around 350 years ago, in 1666
the Danish geologist and anatomist Niels Stenson made a fascinating,
and equally as terrifying realization, as he examined the carcass of a great white shark
Glossopetrae, so-called tongue stones, up to 18 centimeters or 7 inches big,
broadly triangular fossils- which at the time were believed to be petrified tongues, of giant snakes and Dragons...
Were actually a giant shark teeth.
Teeth so big, they easily dwarfed the teeth of the great white shark he had examined.
Virtually everyone, who has since then gazed upon one of these teeth, must have found it impossible,
to resist imagining the sheer enormity of the fish it belonged to.
Because Megalodon teeth are very similar in overall form,
to those of the living great white shark,
just three times as big.
Early paleontologists assume that it must be a descendant of Megalodon.
This view is still held by many paleontology enthusiasts, even today.
But what do experts now say, regarding the relationship of these two sharks?
That's what we are going to find out in this episode of facts in motion.
The evolution of Megalodon, and its relationship to the great white shark
Megalodon first appeared around 16 million years ago.
With a maximum total length of 18 meters or 60 feet and an approximate mass of up to 60 metric tons,
It is the biggest shark that has ever lived.
To put this into perspective,
This makes it about as long as one and a half American school buses,
and about as heavy as 10 African elephants.
It's large size may have been the result of the evolutionary arms race, with water living mammals.
Predecessors of today's whales,
which reinvaded the sea around 50 million years ago.
for the Sharks of that time, sharks like Otodus-
an ancestor of Megalodon-
this meant a sudden abundance of food,
for everyone that was big enough to eat it.
Fossil records show,
that these sharks fed on ancient whales,
more or less from the earliest beginnings.
And as the whales grew bigger, and more diverse,
so did the Sharks.
This evolutionary event, did initiate the Carcharocles lineage,
which would ultimately lead to a Carcharocles Megalodon,
Some 40 million years later.
By that time this genus of sharks had doubled in length,
Multiplied in weight,
and their teeth had evolved from a form that was more suited for eating bite sized prey,
to a form that could reduce even the largest animals to manageable pieces.
A form that we still find in great white sharks today.
And that- in the case of Megalodon-
was perfect for consuming even the largest whales of his time.
Around 11 million years ago, another familiar face appeared,
the great white shark.
However, closer study of the teeth,
showed that it is not -as previously thought-
a direct descendant of Megalodon,
nor are they very closely related.
Instead, researchers agree that the great white evolved separately,
most likely from ancient Mako sharks.
The shark that is believed to be their last common ancestor,
Cretolamna,
appeared already around 130 million years ago, and was one of the most successful of all shark general
and was one of the most successful, of all shark genera,
Spreading across the globe, and living for over 100 million years, only going extinct some 13 million years ago.
these, only four meter long sharks,
probably initiated both the great whites,
and megalodons lineage sometime between 60 and 100 million years ago.
The reason Megalodon teeth are so similar in overall form to those of the Great white shark,
is -according to researchers- due to convergent evolution.
Which means an independent evolution of the same form, because of a similar function,
In this case, cutting out large pieces of flesh.
Otherwise, the teeth of Megalodon show some notable differences, from those of the great white.
They are much thicker, with a convex cross-section, the serrations are much smaller, and more regular.
There is a dark Chevron shaped region called Bourlette between the root and the smooth plate, and the root itself resembles a V,
While that of the great white is nearly rectangular.
Furthermore, even though these two sharks coexisted for roughly 10 million years, they probably rarely met.
Ever since its appearance, some 16 million years ago, Megalodon had been an inhabitant of relatively warm waters, of subtropical and tropical latitudes.
Fossil evidence shows, that they used the shallow seas of Middle America
As nursery sites, where threats for juveniles were minor, and the food plentiful.
The great white shark, on the other hand, inhabited primarily cool waters of the northern Atlantic,
Where they fed on seals and smaller fish, and seemed to have avoided warm areas that were preferred by Megalodon.
These significant differences caused paleontologists
to believe that the great white shark doesn't share a genus, or even a family with Megalodon.
Moreover, no other extant species does, as it is believed that megalodon's genus and family disappeared from our oceans with him,
1.6. Million years ago.
