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The
American walnut tree in my garden in England
is twenty years old now. I planted it with
a plan to pickle walnuts: the trees
only start to bring out the fat green pods
of the coverings over the 'nuts' when they
are twelve years old or so. Now
I get a good crop, if I can beat the grey
squirrels to the harvest. I have
not been able to find out the difference
between the American walnut and a
European one: the grey squirrels who are
my competitors were native to Northern America
and when released into the wild
in England demonstrated an explosive breeding
edge over the native reds, who now
only survive in conifer plantations in
Scotland. The red squirrel wipe-out happened
when I was a child, and everyone was sentimentally
on the side of the undersquirrel, without
understanding in the least how the greys
were wiping out the opposition. Opinion
was that American history was somehow
repeating itself in the animal kingdom in
some zany kind of reversed geography,
where the grey squirrels were the
ruthless American settlers and the red squirrels
were of course noble native 'red' indians.
However, no evidence of squirrel-by-squirrel
massacre was ever found. The truth, unpopular
as ever, slowly emerged. The greys
were expanding because they had
the edge in their more tolerant digestion. Reds browsed on a narrow
spectrum of nuts. The less fastidious diet
of the greys meant that there was always
plenty to spare and the greys were
able to have larger families than the reds.
So the greys prospered at the expense of
the reds, all without a shot being fired,
(Except by humans, at the pesky
little varmints) and arguably without the
participants in this dance of selection realising
the effect they were having on each other.
The red species today is corralled into plantations
of pine in Scotland where a pine-nut-rich
diet allows them a toe hold. It's also
perfectly possible that the two are interbreeding
unnoticed and the red is going into the
DNA junk-yard. In humans, red pigmentation
of hair is a recessive gene. How different
to squirrels are we, after all? Paleontologists
and biologists are keen to point to
a humbling forbear for all mammals; a generically
rat like creature that may well have
had a red bushy tail, to steady its reckless
leaps through the forests of Gondwona, the
mythic One Continent, before the Americas
stopped snuggling into the Bight of
Benin, broke away, and set off across the
world, inventing a brand-new Wide Blue Yonder.
Nowadays the tectonic plates responsible
for the creation of the Atlantic grow apart
at around the pace of growth of a red
squirrel's claw. I guess that New York is
two feet further away from me, since the
day I planted an American Walnut, and two
yards further than when the Yankee squirrels
arrived in their aerial wagon trains and
set up house in the trees in their 'drays'
-- a word whose origins, despite the
existence of the most powerful computers in creation remain
obscure. I conclude there are some things
we may never know.
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