Spain's Bears Stop Hibernating
Rossella Lorenzi, Discovery News Dec. 22, 2006
Bears appear to have stopped hibernating in Spain's northern mountains, according to Spanish scientists who blame climate change for the behavior.
Of the 130 Cantabrian brown bears living in that region, a few females with cubs have been found awake in a season when bears - all bears - typically slumber.
They are the first bears known not to hibernate in Europe, naturalists from La Fundación Oso Pardo (the Brown Bear Foundation ) said.
"Mild winters mean that it is energetically worthwhile for the females to stay awake and search for nuts and berries," Guillermo Palomero, the foundation's president and coordinator of a national plan for bear conservation, told the Spanish daily El Pais.
Palomero added that other signs of winter bear activity have been observed "with absolute certainty" in the past three years.
While it is impossible to prove definitively that these changes in ursine behavior are the result of global warming, "everything points in that direction," according to climatologist Juan Carlos García Cordón, professor of geography at the University of Cantabria in Santander, Spain.
Normally bears begin hibernation between October and December, and remain dormant through most of the winter to bypass the scarcity of their food supply - mainly nuts and berries. They resume activity between March and May.
But according to Palomero, even for the Cantabrian male bears who do slumber throughout the winter, the hibernation period is getting shorter every year.
"We are seeing the most dramatic negative consequences of global warming in the most cold-adapted species," University of Texas biologist Camille Parmesan told Discovery News.
Parmesan is the author of the most comprehensive synthesis of the impact of climate change on terrestrial, marine, and freshwater species.
Published in the December issue of the Annual Review of Ecology, Evolution, and Systematics, her review compiles 866 scientific studies on the ecological effects of human-induced climate change and shows that global warming has already caused extinctions in the most sensitive habitats.
"Polar species, such as polar bears in the Arctic and Adélie and emperor penguins in the Antarctic, are suffering massive population declines," Parmesan said.
A species that now occupies a mountaintop can't go any higher, which is why two-thirds of cloud forest frogs in Costa Rica have already gone extinct, Parmesan said.
Her analysis shows that global warming will continue to cause more extinctions over the next century.
Douglas Futuyma, professor of ecology and evolution at the State University of New York in Stony Brook, agrees.
"There is a grave concern about the prospects of a great number of species," he said. "They are likely to be harmed by temperature changes, by mismatch between their life cycles and the altered seasonal life cycles of species...on which they depend, and by invasion of competing species that are better adapted to warmer conditions."
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