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Scientists Reveal That Bears Have Stopped Hibernating
By Geneviève Roberts
The Independent UK
Thursday 21 December 2006
Bears
have stopped hibernating in the mountains of northern Spain, scientists
revealed yesterday, in what may be one of the strongest signals yet of
how much climate change is affecting the natural world.
In
a December in which bumblebees, butterflies and even swallows have been
on the wing in Britain, European brown bears have been lumbering
through the forests of Spain's Cantabrian mountains, when normally they
would already be in their long, annual sleep.
Bears
are supposed to slumber throughout the winter, slowing their body
rhythms to a minimum and drawing on stored resources, because frozen
weather makes food too scarce to find. The barely breathing creatures
can lose up to 40 per cent of their body weight before warmer
springtime weather rouses them back to life.
But
many of the 130 bears in Spain's northern cordillera - which have a
slightly different genetic identity from bear populations elsewhere in
the world - have remained active throughout recent winters, naturalists
from Spain's Brown Bear Foundation (La Fundación Oso Pardo - FOP) said
yesterday.
The
change is affecting female bears with young cubs, which now find there
are enough nuts, acorns, chestnuts and berries on the bleak
mountainsides to make winter food-gathering sorties "energetically
worthwhile", scientists at the foundation, based in Santander, the
Cantabrian capital, told El Pais newspaper.
"If
the winter is mild, the female bears find it is energetically
worthwhile to make the effort to stay awake and hunt for food," said
Guillermo Palomero, the FOP's president and the coordinator of a
national plan for bear conservation. This changed behaviour, he said,
was probably a result of milder winters. "The high Cantabrian peaks
freeze all winter, but our teams of observers have been able to follow
the perfect outlines of tracks from a group of bears," he said.
The
FOP is financed by Spain's Environment Ministry and the autonomous
regions of Cantabria, Asturias, Galicia and Castilla-Leon, where the
bears roam in search of mates. Indications of winter bear activity have
been detected for some time, but only in the past three years have such
signs been observed "with absolute certainty", according to the
scientists.
"Mother
bears with cubs make the effort to seek out nuts and berries if these
have been plentiful, and snow is scarce," Mr Palomero said, adding that
even for those bears - mostly mature males - who do close down for the
winter, "their hibernation period gets shorter every year".
The
behaviour change suggests that global warming is responsible for this
revolution in ursine behaviour, says Juan Carlos García Cordón, a
professor of geography at Santander's Cantabria University, and a
climatology specialist.
"Meteorological
data in the high mountains is scarce, but it seems that the warming is
more noticeable in the valleys where cold air accumulates," Dr García
Cordón said. "There is a decline in snowfall, and in the time snow
remains on the ground, which makes access to food easier. As autumn
comes later, and spring comes earlier, bears have an extra month to
forage for food.
"We cannot prove that non-hibernation is caused by global warming, but everything points in that direction."
Spanish
meteorologists predict that this year is likely to be the warmest year
on record in Spain, just as it is likely to be the warmest year
recorded in Britain (where temperature records go back to 1659).
Globally, 2006 is likely to be the sixth warmest year in a record going
back the mid-19th century.
Mark
Wright, the science adviser to the World Wide Fund for Nature (WWF) in
the UK, said that bears giving up hibernation was "what we would
expect" with climate change.
"It
does not in itself prove global warming, but it is certainly consistent
with predictions of it," he said. "What is particularly interesting
about this is that hitherto the warming has seemed to be happening
fastest at the poles and at high latitudes, and now we're getting
examples of it happening further south, and heading towards the
equator.
"I
think it's an indication of what's to come. It shows climate change is
not a natural phenomenon but something that is affecting not only on
the weather, but impacting on the natural world in ways we're only now
beginning to understand."
The
European brown bear, with its characteristic pelt that ranges from dark
brown through shades of grey to pale gold, has black paws and a tawny
face. It has poor vision, although it sees in colour and at night, and
if threatened rears on its hind legs to get a better view. It can live
for up to 30 years. It has acute hearing, and an especially fine sense
of smell that enables it to detect food from a long distance. It is
carnivorous, but has a multifunctional dental system with powerful
canines and grinding molars perfectly adapted to an omnivorous diet.
The animals would normally begin hibernation between October and December, and resume activity between March and May.
The
Cantabrian version of the brown bear, a protected species, was once as
endangered as the Iberian lynx or the imperial eagle still are in
Spain, but is now recovering in numbers. Between 70 and 90 bears roamed
Spain's northern mountains in the early 1990s; now 130 live there.
Other Seasonal Freaks
- The
osprey found in the lochs and glens of the Scottish Highlands in the
summer months, usually migrate to west Africa to avoid the freeze. This
winter, osprey have been spotted in Suffolk and Devon. Swallows, which
also normally migrate to Africa for the winter have been also seen
across England this winter.
- The red admiral butterfly, below, which hibernates in winter,
has been spotted in gardens this month, as has the common darter
dragonfly, usually seen between mid-June and October, which has been
seen in Cheshire, Norfolk and Hampshire.
- The smew, a diving duck, flies west to the UK for winter from
Russia and Scandinavia. This year, though, they have been mainly absent
from the lakes and reservoirs between The Wash and the Severn.
- Evergreen ivy and ox-eye daisies are still blooming and some
oak trees, which are usually bare by November, were still in leaf on
Christmas Day last year.
- The buff-tailed bumblebee is usually first seen in spring.
Worker bees die out by the first frost, while fertilised queen bees
survive underground between March and September. This December, bees
have been seen in Nottingham and York.
- Primroses and daffodils are already flowering at the National
Botanic Garden of Wales, in Carmarthenshire. 'Early Sensation'
daffodils usually flower from January until February. Horticulturalists
put it down to the warm weather.
- Scientists in the Netherlands reported more than 240 wild
plants flowering in the first 15 days of December, along with more than
200 cultivated species. Examples included cow parsley and sweet
violets. Just two per cent of these plants normally flower in winter,
while 27 per cent end their main flowering period in autumn and 56 per
cent before October.
Go to Original
A Shock to the Ancient Rhythms of the Natural World
By Michael McCarthy
The Independent UK
Thursday 21 December 2006
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.
(In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. h o t g l o b e has no affiliation whatsoever with the originator of this article nor is h o t g l o b e endorsed or sponsored by the originator.)
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