Climate Change Upside: Fatter Marmots in a Mood to Mate

Considering the drumbeat of depressing news about how climate change is affecting the planet - the latest being a warning that over one-third of the lower 48 states will face higher risk of water shortages by mid-century - today's lead starts with something other than the usual bummer.

A new study in the journal Nature finds that mountain marmots are waking up earlier from hibernation because of longer summers. The upshot:They are getting more time to feed their little faces and then reproducing earlier than usual. That change in the marmot calendar offers their offspring an advantage in getting through the winter.

During hibernation, a marmot will lose around 40 percent of its body mass so their ability to pack it on during prime eating months also works to the general population's advantage. Marmots, which mate starting when they are about two years old, live up to 15 years.

"Marmots are awake for only four to five months of the year. These months are a busy time for them - they have to eat and gain weight, get pregnant, produce offspring and get ready to hibernate again," said Arpat Ozgul, lead author of the study. "Since the summers have become longer, marmots have had more time to do all these things and grow before the upcoming winter, so they are more likely to succeed and survive."

The study was carried out between 1976 and 2008 by several universities, including London's Imperial College London, where Ozgul teaches in the Department of Life Sciences.

Ozgul said that researchers have observed changes in the body mass of individual marmots over the course of the last three decades - as well as changes in their population size over the last 10 years. But he hesitated to predict what might happen next. "Will populations thrive in the changing climate? We suspect that this population increase is a short-term response to the lengthening summers. We hope that by continuing this long-term study we will shed important light on the marmots' future response to climate change," he said.