Climate change is making the animals shrink. A few months ago, I wrote about how female seals north of Antarctica were breeding smaller pups because of fewer food resources attached to ice. But they’re not the only ones. Mountain goats are getting smaller, too.
Researcher Tom Mason started studying the Chamois mountain goat–a rock-hopping, primarily European species prized for its meat and leather–for a thesis on the impacts of climate change on the animals. But when he and fellow researchers began poring over Italian goat-hunters’ records detailing the age and weight of their kills, they noticed something strange. Over the course of the last four decades, it appears that the Chamois mountain goat has shrunk by an average of 25%.
“A species like Chamois are hunted–they’re an important source of meat for local people,” Mason, who published his work in Frontiers in Zoology, says. “This could mean there’s a reduced food source now.”
By looking at weather station data and satellite photos of the types of plants the goats eat, Mason was able to determine that it wasn’t lack of food that had put the goats on a crash diet. Temperatures have increased in the central European alps by three or four degrees in spring and summer, which pushes the goats to rest in the shade rather than go out in pursuit of food.
“Shrinking animals is a fairly widespread phenomenon, and [research] usually finds that climate change is changing vegetation or resources somehow,” Mason says. “What we found is that the vegetation hasn’t really changed much. We think temperatures are most likely directly affecting the [goats’] behavior and physiology.”
Mason notes that similar patterns have been found across various mammals, birds, and fish. Last year, scientists studying a miniature, prehistoric horse species concluded that climatic changes at the time determined the horse’s size. But climate change isn’t only making some species smaller–it’s also making others bigger. In 2011, a San Francisco State University study found that central Californian birds had grown larger over the last several decades, possibly because they took on more fat storage to survive in extreme weather.