Climate Change Is Causing Mountain Goats To Shrink

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Group of chamois in Slovakia.

Forget melting glaciers, acidifying oceans and changing weather patterns: climate change is now going after goats.

New research has found that climate change is causing mountain goats living in the Alps to shrink. The study, which was published Tuesday in the journal Frontiers in Zoology, found that adolescent Alpine chamois mountain goats are significantly smaller than their peers were 30 years ago, weighing about 25 percent less than goats in the 1980s did. The researchers called this change in body mass over 3 decades “striking.” They also said the shrinking “appears to be strongly linked” with increased temperatures in the growing season of the goats’ Alpine habitats.

The study noted that climate change has been linked to changes in body mass of other species before. But in those situations, the mass change was typically due to a change in the amount of food available or in the timing in which food was available — changes in bud burst timing in the spring, for instance. That wasn’t the case in the goats’ situation, however.

“Instead, our results provide support for our second putative driver: that climate change could be directly affecting chamois behaviour or physiology, limiting their ability to acquire resources,” the report states.

The researchers note that in ungulates, a group of mammals that includes goats, cows, horses and other hoofed animals (though whales and dolphins are also sometimes included), “behavioural changes, such as allocating less time to foraging, play an important role in thermoregulation.” This means that, to avoid getting too hot, the chamois goats don’t forage for food as much during the hottest parts of the day, and don’t forage as much in general when the temperature remains high throughout the day. If chamois eat less during warmer growing seasons, they aren’t likely to reach the same body mass as goats who lived through cooler growing seasons.

“Higher daily temperatures during spring and summer may have led to juvenile chamois spending more time resting and less time foraging than in the past, reducing their ability to store energy reserves and invest in growth,” the report states.

As National Geographic points out, the goats’ smaller size may help them better withstand hotter summers, simply because they have a greater surface area to body mass ratio. However, a lower body mass may also mean the goats aren’t as prepared for harsh Alpine winters.

As the study notes, this isn’t the first time that scientists have discovered climate change to be behind changes in animal body mass. Six species of salamander in the Appalachian Mountains have been growing shorter over the last 50 or so years, with salamanders living in the southernmost sites that researchers visited showing the most shrinkage. And shrinking sea ice is in turn leading to smaller polar bears — the lack of sea ice means polar bears can’t hunt like they used to, and end up spending less time eating and gaining weight.