the humble hermit crab
harmless
and traditionally
small
except for this member of the family
the coconut crab
or robber crab
the largest land crab on earth
the south pacific islands of vanuatu are
pretty hard to reach
having the place mostly to themselves it
seems these critters have taken the
opportunity to grow as big as
medium-sized mammals
their legs can span a metre
and they’re strong enough to lift the
equivalent of ten house bricks
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being big has allowed them to cultivate
some rare talents
true to their name they can crack a
coconut
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and they’ve been known to kill and eat
rats
but there’s one thing these crabs simply
can’t do
and that is swim
this crab lives its adult life entirely
on land so you’d think this wouldn’t be
too much of a problem
and for most of their days
it isn’t
but once a year the females of these
colossal crustaceans have no choice but
to brave the waves in order to pass on
their genes
this female has been nursing her
fertilized eggs on her abdomen having
mated some weeks ago
but tonight’s the night to release her
precious cargo
and like all crabs
that’s done in water
she must tread carefully
she’s so well adapted to land that she’s
evolved a form of lung that can no
longer breathe underwater
and her great weight
means if she gets out of her depth
she’ll sink
and drown
clinging for life
she releases her eggs into the waves
they’ll hatch into swimming larvae
but in a month’s time they’ll be back on
land
there they too
will grow into terrestrial giants
