christmas island
in the indian ocean for millions of
years this remote speck of land
has been ruled by crabs
their ancestors came from the sea but
most have now
adopted a land-based existence
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given there are so many of them they get
along relatively harmoniously
they’re the gardeners and caretakers
of a tiny crab utopia
once a year they must all return to the
sea to breed
and the march of the red crabs is one of
the greatest
natural spectacles on earth
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there are 50 million of them
it’s an event this has brought the
island worldwide fame
but in recent years millions of red
crabs haven’t managed to reach
the sea
an invader has occupied this island
yellow crazy ants
they escape from visiting ships and with
no predators to control them
they have now created vast super
colonies
in the forest
when migrating red crabs march into
their territory
the ants attack
squirting acid into the crabs eyes and
mouths
the crabs have no defense
blinded and confused they’re doomed
humans brought these ant invaders here
and now humans are having to control
them
isolated communities may evolve for
millions of years
in relative peace but when
new challenges arrive they can struggle
to cope
of all the species that have become
extinct in recent years
around 80 percent have been islanders
