By Susan Milius
Climate change now hits home for tongue twister fans. Shorter, sweeter winters shrink sheep, scientists say (slowly).
Female wild Soay sheep on the remote North Atlantic island of Hirta have shrunk by about 5 percent during the past two decades, says Tim Coulson of Imperial College London’s campus in Berkshire. To see what’s driving that change, a weight loss averaging 81 grams per year, Coulson and his colleagues applied a new analytical approach to a mountain of data. It turns out that evolutionary forces favor the opposite trend, toward bigger sheep. But environmental changes have softened winters, overwhelming those evolutionary effects, the team reports online July 2 in Science.
For climate change, “the effects people tend to focus on are the ecological ones,” Coulson says. Studies have documented creatures shifting their ranges or changing the timing of migrations or blooming. “We’re showing that the effects extend beyond the ecology, down to individual attributes,” Coulson says.