The real reason dodo birds went extinct - Leon Claessens
Dodos are commonly considered
brainless, blundering birds
that were poorly adapted
and doomed to die off,
making their human-mediated extinction
effortless and inevitable.
But that's not the case.
So, what were dodos actually like?
And what really caused their downfall?
Let's start at their origin.
Okay, rewinding more than
20 million years,
some tropical pigeons from Southeast Asia
voyaged across the Indian Ocean,
perhaps by gradually journeying
from island to island.
Eventually, their descendants came to a
remote archipelago east of Madagascar.
Those that settled likely
diversified over time.
Then, about 8 million years ago,
an underwater volcano formed another
island on the chain,
which would come to be known as Mauritius.
Some of the birds populated
this new island, too,
and down the line,
dodos emerged as a distinct species.
They shared Mauritius with bats, lizards,
giant tortoises, and other birds.
The closest large predators were held
back by about 800 kilometers of ocean,
so getting murdered was basically
a non-issue.
Without the need for defensive
adaptations, like flight,
expending energy on them
would have been wasteful.
So, as with the kākāpōs of New Zealand
and the cormorants of the Galápagos,
their flight muscles shrank.
Dodos probably nested
on the island's forest floor,
feasting on fruits and seeds.
Reaching just under a meter tall,
they were among the island's
largest animals.
And they were well-adapted
to their environment,
which could fluctuate between extreme dry
and wet conditions.
They also survived some major disruptions.
Around 4,300 years ago,
a megadrought caused waves
of mass mortality events on Mauritius.
Fresh water grew scarce
and lakes likely grew saltier
and became treacherous traps.
This lasted for around 150 years.
However, dodos prevailed...
until a few millennia later,
when everything changed— quickly.
In 1598, Dutch sailors came
ashore on Mauritius,
and the island soon became
a welcome stopover for their trade ships.
The sailors described natural wonders,
including large numbers of birds
twice as big as swans
and tortoises with shells huge enough
to fit 10 men.
Mauritian animals hadn't evolved
to fear being hunted by humans,
so they were an easy catch.
Sailors ate some dodos,
but this alone didn't cause their doom.
The Dutch sailors came with company.
They brought macaques
that were probably pets.
They released goats and pigs
on the island to establish food sources.
And at some point, sailors also
inadvertently introduced rats.
It's thought that goats and pigs grazed
and rooted through the forest understory,
which dodos lived in;
pigs, macaques, and rats preyed
on dodo eggs and chicks;
and all of them competed with dodos
for resources.
Dodos were last seen less than a century
after Dutch arrival.
At the time, people didn't recognize
that species could disappear.
It wasn't until a century later,
in the 1790s,
that a scientist conclusively demonstrated
the concept of extinction.
By then, many thought dodos were fake.
But discoveries from digs and sparse
remains helped confirm their existence.
Nevertheless, representations of dodos
were misleading.
One popular natural history text
of the late 1700s
characterized them as stupid,
voracious, and grotesque.
Once Lewis Carroll included a dodo
in "Alice's Adventures in Wonderland"
in 1865,
the birds quickly amassed popularity.
But dodos continued being framed as inept,
clumsy, lazy, and unfit for survival
in scholarly works, satirical magazines,
and children's poems alike.
And yet, there's no evidence that dodos
were less intelligent
than their relatives.
The dodo's brain size relative to its body
was similar to that of other pigeons.
And especially rotund dodo depictions
are misleading.
They may have been inspired by what dodos
looked like during mating displays
or in captivity—
or they were just
poor artistic renderings.
Scientists think dodos were
fairly muscular birds.
All in all, the dodo was, in fact,
a survivor
that withstood major natural disasters
and thrived on its island home.
It simply wasn't prepared for a sudden
onslaught of invasive species.
And neither were other
endemic Mauritian animals,
including raven parrots, fruit bats,
and giant tortoises.
In the aftermath, perhaps it was easier
to declare the dodo's extinction
the result of its personal failing
than to admit it was a human one.
