Climate Change vs Mother Nature: Scientists 
reveal that bears have stopped hibernating

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 

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 

* 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 

* 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