Climate change is changing the size of sheep on a Scottish isle:
While every physics pupil knows that heat can usually be relied on to make objects expand, for the semi-wild sheep of the Outer Hebrides it appears to have the opposite effect.
Observations of Soay sheep on Hirta island have shown that the warmer temperatures associated with global warming allow more smaller animals to survive the winter. And with greater numbers of smaller sheep living through the cold months, the average size of the animals falls.
Research led by Imperial College London, published in the journal Science, is the first to establish a direct link between the genetic changes of an animal population and climate change. It indicates that mankind, on top of the ecological legacy of causing species to become extinct or vastly reduced in number, is leaving an evolutionary legacy by affecting natural selection.
On Hirta, the researchers used a combination of population data and field observations to track the size of individual sheep and how their survival rates influenced their numbers.
It's the mass to surface ratio there, smaller sheep just couldn't control their temperatures in the colder winters. So who says climate change is all bad then?
