A
shock To The Ancient Rhythms Of The Natural World
By Michael McCarthy
22 December 2006
The
Independent
Animals
that hibernate in winter abandoning hibernation: yet another signal
that something momentous is happening to the rhythms of the natural
world, in the way in which we have always understood them.
Consider what a significant
disruption of a life pattern this is. Hibernation has evolved for the
same reason most animal behaviour has evolved: as a strategy to maximise
survival. Some creatures that need a lot of energy to get around have
learnt to shut themselves down in the winter months, when the food to
provide that energy is simply not available (or too much energy would
be expended in searching for it). Zoologists have realised in recent
decades that many species have an instinctive and finely tuned way of
weighing up the balance between how much effort needs to be expended
to acquire a certain food item, and how much energy is available, in
return, in the item acquired. The general law is: if the second is less
than the first, don't do it. This has been christened "optimal
foraging".
Hibernation could be seen
as a version of this: if the food search is going to be hopeless, it
makes sense to stop foraging altogether. Instead, fatten yourself up
before the hopeless time, then sleep it out. This is a strategy that
has evolved - in bears, hedgehogs, bats and other species - over millions
of years and it has persisted as a piece of behaviour because it has
been successful.
If some European brown bears
in the Cantabrian mountains are now stopping hibernation, we can draw
two conclusions. First, something quite enormous is happening in the
world around them, and if you want to hazard a guess that that something
is global warming, you would have as good a theory as any other.
Second, they are abandoning
a survival strategy - which has been successful - for the unknown. What
if they give up hibernation because of rising winter temperatures, but
then when they are active in winter, are unable to find enough food?
We are already witnessing
what a problem such disruption of natural cycles can cause for other
creatures. In Britain, insects are hatching earlier in the spring, but
migratory birds that depend on the "flush" of caterpillars
to feed their young are coming back at the same time as they have always
done, and thus may be starting to miss out on the feast: this may be
one of the reasons why many of our woodland birds are now in sharp decline.
Climate change is perceived
as a terrible problem for human society, and rightly so; but we should
not lose sight of the fact that, to the natural world and its inhabitants,
the warming also presents a mortal predicament.
© 2006 Independent News
and Media Limited
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