Many years ago, I bought a beautiful wool sweater in Scotland. It was cream colored cable knit and I loved it. I wore it while traveling and it got a bit filthy. While in France, I decided to wash it at a public Laundromat and set the machine to C for Cold. The only problem is that in France C stands for Chaud, which means hot, and my sweater came out of the wash the size and weight of a small brick. It was upsetting.

It turns out the same principle that applies to Scottish wool actually applies to Scottish sheep; get them too hot and they shrink.

According to the Associated Press:

On average, wild Soay sheep on Scotland's island Hirta are 5 percent smaller today than they were in 1985, according to a team of researchers led by Tim Coulson of Imperial College London. "The decrease in body size was due to a reduction in growth rates caused, in part, by the changing climate," Coulson said in an interview via e-mail.

This is because the warmer the weather, the less quickly the sheep need to grow to survive and the more small sheep survive the winter and breed and create more small sheep. Scientists also theorize that climate change is causing ewes to beginning breeding younger than usual, which results in smaller sheep.

It shows how evolution and ecology each play a role in change, Coulson said: "And that, for our wild sheep at least, climate change is having a detectable effect on body size — a trait that is partly determined by genes — and that this compliments previous research showing how climate change can influence population size."

The shrinking of the Scottish sheep has baffled researchers until now.

Evolutionary theory holds that species get bigger and stronger over time because larger, more dominant animals are more likely to reproduce. – CBC News

The 5% decrease in average body size during the 24 year period studied is right in line with increases in global temperatures and disruptions in historic climate patterns.

While greater survival rates may be good news for small sheep, it’s bad news for species, overall. It demonstrates that human activities are not only destroying habitats and food supplies, but disrupting natural evolutionary trends.

As ScientificBlogging writes, “Yep, climate change can trump natural selection, it turns out.”