Why did Megalodon go extinct? - Jack Cooper and Catalina Pimiento
In 1667, a Danish scientist finally
concluded that certain mysterious stones
prized for their supposed
medicinal powers,
hadn’t fallen from the sky
during lunar eclipses
and weren’t serpent tongues.
In fact, they were fossilized teeth—
many belonging to a prehistoric species
that would come to be called megalodon,
the biggest shark to ever live.
So what was it like when megalodon
ruled the seas?
And what brought this formidable
predator to extinction?
Because their skeletons
were cartilaginous,
what remains of megalodons are
mostly scattered clues,
like some isolated vertebrae and
lots of their enamel-protected teeth.
Like many sharks, megalodons could shed
and replace thousands of teeth
over the course of their lives.
Interestingly, some fossil sites harbor
especially high numbers
of small megalodon teeth.
Experts believe these were nurseries
that supported countless generations
of budding megalodons.
They grew up in sheltered
and food-packed shallow waters
before becoming unrivaled
adult marine hunters.
Looking at the similarities
with great white shark teeth,
scientists estimate that megalodons might
have stretched up to 20 meters—
three times longer than great whites.
And during their reign, which began
around 20 million years ago,
megalodons lived just about everywhere,
with individuals also potentially
undertaking transoceanic migrations.
The world was warmer and the ocean
was brimming with life.
Otters and dugongs thrived
in newly formed kelp forests,
and baleen whales were
at their most diverse.
Megalodons had no shortage
of high-energy, edible options.
And it seems they were ambitious eaters.
Generally, as carnivores consume
protein-rich meat,
certain nitrogen isotopes accumulate
in their tissues—
including the enamel of their teeth.
Analyzing megalodon teeth, scientists
confirmed they were apex predators
that not only ate large prey species—
but also other predators,
perhaps even each other.
In addition to megalodon’s teeth,
researchers have access to one
exceptionally well-preserved spinal column
that comprises 141 vertebrae
of a 46-year-old megalodon.
A 3D model of the megalodon’s body
suggests that its stomach
could reach volumes
of almost 10,000 liters—
big enough to fit an entire orca.
Reconstructing their jaws,
researchers think megalodons could eat
a now-extinct 7-meter sperm whale
in as few as four bites.
And the fossilized bones of ancient
cetaceans do indeed show evidence
of megalodon bite marks—
including some that healed over,
confirming that megalodons
pursued live prey.
But if megalodons were so powerful,
why did they go extinct?
It seems there were a few
contributing factors.
By the time they disappeared
around 3.5 million years ago,
the global climate had cooled,
causing more glaciers to form
and the sea level to drop.
This dried up many coastal habitats,
meaning some of the world’s most
resource-rich marine sites were lost.
About a third of all marine megafauna
eventually went extinct,
so fewer prey species were available.
And megalodons already faced high
energetic demands because of their size
and the mechanism they likely used
to regulate their body temperature,
which allowed them
to navigate cold waters
and attack prey with bursts of speed.
Environmental changes may have
made megalodons vulnerable
and increasingly put them in competition
with other predators,
including the great white shark,
a relative newcomer.
Because megalodons were highly
mobile predators,
their extinction had global consequences.
The end of their long-distance travels
probably disrupted nutrient transport
between different ecosystems.
And many animals were suddenly released
from the immense predatory pressure
of their bite.
Interestingly, some marine mammals
dramatically increased in size afterwards,
which was perhaps partially afforded
because they were no longer dealing
with such a mega-existential threat.
Knowing that the decline of apex predators
can destabilize entire ecosystems,
conservationists are working to prevent
today’s sharks from facing a similar fate—
this time, because of humans.
And meanwhile, the megalodon remains
a colossal testament
to ecological interdependence
and millions of years of bones well-bitten
and waters well-wandered.
