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Published: 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 thebleak 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 co-ordinator 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.
Geneviève Roberts