Counting Sheep

Sheep on the remote Scottish Island of Hirta have been shrinking an average of 5% every year, not because of natural selection, scientists say, but because of global warming. Climate change has shortened the harsh winters on the island, which means that the smaller ewes that wouldn’t have survived previous years now stay in the gene pool and decrease the average size of the entire population. UCLA ecologist Malcolm Gordon suggests that the warming trend may have also caused “changes in the chemical composition and nutritional value of the plant foods” that the sheep graze on. Although the causal relationship has yet to be proven, Scotland’s shrinking sheep are indicative of the far-reaching consequences of rising temperatures on even the most remote ecosystems.

image: "Sheep" by Jax60 on Flickr via Creative Commons licensing.