Yellow-bellied marmots have benefited from a warming climate that has shortened the hibernation season and lengthened feeding seasons for young and adults alike.

A retired Kansas University distinguished professor has found that climate change has helped a population of yellow-bellied marmots in Colorado.

Kenneth Armitage, an ecology and evolutionary biology professor, has been studying the rodent since 1962. Recently, warmer temperatures have allowed marmots to emerge from their hibernation earlier.

Warmer temperatures mean earlier snowmelt, which means plants appear sooner, Armitage said. With more fat left from their hibernations, the rodents have more energy to begin foraging and reproducing earlier. The earlier the young are born, the more time they have to get fat enough to survive hibernation, Armitage said, leading to healthier, bigger and more plentiful rodents.

Marmots are mammals that resemble large, ground-dwelling squirrels — groundhogs, for example, are technically classified as marmots.

Armitage chose to begin studying them years ago because he was interested in observing if social behavior would have an impact on population sizes.

He chose to study marmots because they are active in the daylight, live in easy-to-find burrows and are social.

“Initially, I kept the study going for various reasons,” as he discovered new issues and problems he’d like to explore, he said.

“I had no idea that climate change was going to be a factor back in the 1960s,” he said.

Today, looking back on his career, he said he was glad he kept it up. Climate change studies require a large amount of data, and studies of mammals in one area for such a long period of time are rare, Armitage said.

“It makes one feel pretty good to know that what one did had an impact,” he said.

There’s a bit of irony to the results of the study, Armitage said. And that’s the fact that if too much snow melts during the winter, it’s actually bad for marmots, because the snow serves to insulate them underground while they’re hibernating.

So, while some warming is good for the marmots, Armitage said he predicted that long-term warming would be detrimental to the population.

The research on the marmots’ demographics is still ongoing today, with the torch having been passed to a new faculty member — study co-author Dan Blumstein at UCLA — after Armitage retired. It is now approaching its 50th year.