Climate change causes larger, more plentiful marmots, study shows

July 21, 2010, University of Kansas
This is a yearling yellow-bellied marmot Credit: Arpat Ozgul

This week, one of the world's foremost scientific journals will publish results of a decades-long research project founded at the University of Kansas showing that mountain rodents called marmots are growing larger, healthier and more plentiful in response to climate change.

The groundbreaking study, published in Nature, is the first to reveal that changes in seasonal timing can increase body weight and simultaneously in a species — findings likely to have implications for a host of other creatures, especially those that hibernate.

Established by Kenneth Armitage, KU professor emeritus of ecology and , the long-standing investigation tracks yellow-bellied marmots in Colorado.

"We started this research in 1962, and every summer we'd record basic such as the age of the animals, gender, , who survived and who reproduced," Armitage said. "At the time we started, we had no idea that climate change was going to be a problem. But we collected that basic demography to use as a foundation for other kinds of study."

Largely because of the KU researcher, yellow-bellied marmots have proven to be a valuable for understanding larger questions. Armitage said that he first chose to study the marmot because it lives in easy-to-find burrows and is active in the daytime, so it is readily observable.

"I didn't intend to spend 40 years studying marmots, but new questions kept coming up — physiological, hibernation, genetics and so on," Armitage said. "It turned out that long-term studies of our kind are quite rare. Yet, it's precisely the kind of data that you need to determine what climate change is going to do."

The findings result from collaboration between a number of international researchers who used fieldwork by Armitage to underpin their analyses. Both Arpat Ozgul, lead author of the study from Imperial College London, and Dan Blumstein, a co-author from the University of California-Los Angeles, previously have worked with Armitage on the marmot project.

Using data collected between 1976 and 2008, the authors conclude that a longer growing season has boosted marmots' individual size, overall strength and general population. The average weight of fully grown marmots jumped from 6.82 pounds in the early years of the study to 7.56 pounds in the later half of the study.

Additionally, the population growth of marmots increased from 0.56 marmots per year from 1976 to 2001 to 14.2 marmots per year from 2001 to 2008.

"The warming results in earlier snowmelt, which means that plants appear sooner and the marmots come out of hibernation earlier," said Armitage. "They have more fat left which provides them energy to start foraging. Then they can start reproducing so their young are born earlier and have time to get fat enough to survive hibernation. Most importantly, the reproductive female can survive better. Being able to wean her young earlier, she has a longer season and survival of adult females has increased over the last years."

Although Armitage is happy to see the yellow-bellied marmot thrive, the KU researcher cautioned that the boom in marmots is temporary; he expects that warming could harm them in the long run because of changes in snow patterns.

"This benefit to marmots is probably short-lived," he said. "Snow patterns both benefit and harm marmots. Prolonged snow cover in the spring increases mortality and reduces reproduction. But if there's less snowmelt to nourish plants that marmots forage in the summer, it will severely affect them. In droughts, we've had very high mortality."

Explore further: Marmots are returned to the Dolomites

More information: “Coupled dynamics of body mass and population growth in response to environmental change” Nature, 21 July 2010

Related Stories

Marmots are returned to the Dolomites

June 5, 2006

Twenty pairs of marmots -- Europe's version of the U.S.'s groundhog -- have been reintroduced into Italy's National Park of the Belluno Dolomites.

Marmots can teach us about obesity

June 2, 2010

A nutrient that's common to all living things can make hibernating marmots hungry - a breakthrough that could help scientists understand human obesity and eating disorders, according to a new study by a Colorado State University ...

The alpine marmot spreads into the Catalan Pyrenees

March 9, 2010

Researchers from the Centre for Ecological Research and Forestry Applications (CREAF) and the Autonomous University of Barcelona (UAB) have demonstrated, using a map of the potential distribution, the alpine marmot's capacity ...

Desert Dust Alters Ecology of Colorado Alpine Meadows

June 29, 2009

( -- Accelerated snowmelt--precipitated by desert dust blowing into the mountains--changes how alpine plants respond to seasonal climate cues that regulate their life cycles, according to results of a new study ...

Recommended for you

Looking for LUCA, the last universal common ancestor

December 18, 2018

Around 4 billion years ago there lived a microbe called LUCA: the Last Universal Common Ancestor. There is evidence that it could have lived a somewhat 'alien' lifestyle, hidden away deep underground in iron-sulfur rich hydrothermal ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (1) Jul 21, 2010
Lol!, who'd have thunk it?, the AGW conspiracy is being coordinated by some sort of pro-marmot faction
5 / 5 (2) Jul 21, 2010
AH HA! WE told you! This proves Global Warming is great for the environment.. Those darn tree huggin Al Gore following hippys were wrong all Along! Yeeee-ha!

Sarcasm is great... thought I'd beat these morons to their own rediculous uninformed argument.
5 / 5 (1) Jul 21, 2010
One species advantage is another species weakness. Do you really think you can reach a better balance than god, or billions of years worth of evolution?

Do you want to change the atmosphere in 200 years... Then wait millions of years until the environment is again ideal for humans? It doesn't get any better than it was 100 years ago... we evolved with it.
1 / 5 (2) Jul 21, 2010
Do you want to change the atmosphere in 200 years... Then wait millions of years until the environment is again ideal for humans? It doesn't get any better than it was 100 years ago... we evolved with it.

100 years? Really? :) It WAS pretty good 100 years ago if only for agricultural practices, but that is definitely not the time frame for evolution.
5 / 5 (2) Jul 21, 2010
larger, stronger, more plentiful rodents. Honestly, that scares me more than the loss of the Maldives.
3.7 / 5 (3) Jul 22, 2010
gwargh and Djincs:

Yes, the planet is resilent, it and life can adapt. The problem is the rate. This level of climate change has NEVER occured near this quickly, at least not without a mass extinction event. Ecosystems are like all other life... if you get a cut on your arm, you can heal, but if you cut off your arm, it ain't coming back. Don't think the planet can take unlimited abuse.

Djincs- your right, people moved when the climate changed dranatically... the saraha was once rain forest and changed to desert over 100,000s of years... we are changing things in a couple hundred years... life cannot adapt this quickly.

Yes the problem is largely the animals, plants, and microorganisms. But 6 billion humans cannot survive without them, so massive population declines are highly likely.
5 / 5 (1) Jul 22, 2010
"desandent of survivors who had managed to survive lots of crappy things, we arent that good at being a crap , you can calm youirself with that, and some species will dissapear it is inevitable, it will be strange if it dont happen!"
- Your right, 5 or 6 mass extincts have occured, effectively setting evolution back millions of years. I don't know about you, but I think the greatest sin any man can commit is to destroy the planet. You don't think there is any danger, and if you do, you shrugg it off as "oh, well, everything dies, some form of life will remain". If your that indifferent, then please stay out of the debate, some of us care enough to stop the human race from destroying the planet... some of us would even sacrafice our own species to save the planet if necessary.

"some species will dissapear it is inevitable, it will be strange if it dont happen!"
-agreed, but if this trend continues, MOST species will be extinct.
not rated yet Jul 22, 2010

I don't recall in any way denying climate change. I was merely commenting the 100 year evolution thing.
5 / 5 (1) Jul 22, 2010
gwarth-in that case, you misread my comment. I wasn't saying we evolved in 100 years, I was saying that, when the planet was pristine, that is as good as it gets...We evolved with the planet.. now that link is disintegrating and most people do not understand how vital that link is to our survival.
5 / 5 (1) Jul 22, 2010
Agreed, humans are unique and great... We have the unique ability to control our environment via thought. If we use that to destroy, then I don't think we deserve it and another species should be given a shot.

Mass extinctions can definitely help some species over othersm this is true. Warm blooded isn't better than cold, cold blooded was better for that atmosphere, warm blooded is better for this atmosphere; which do you think will be more advantageous after global warming? Think about it.

yes evolution adapts and "learns lessons" (if you must call it that), but your misrepresenting the process. I.e. adaptation later in time does not mean a better method across all time.

Your crazy if you think CO2 has decreased in the last 50 years, it was on a slow 10k year decline before the industrial revolution. Now it's greater than double what it was before the industrial revolution.

Again, if your oblivously indifferent to the future, stay out of the debate please.
not rated yet Jul 22, 2010
it is good that we are getting it back to the atmosphere, you can ask the plants about that.

Only for a short and immediate time period. More CO2 = faster growth due to sugar abundance, but lower protein concentrations. Search for studies on butterfly and bee populations. Part of the reason they are declining is lack of protein in their diets. And, hilariously enough, lack of pollinators is not good for plants, no matter how much sugar they're getting.
5 / 5 (1) Jul 22, 2010
Poison ivy all across the country is getting more abundant, and the toxin from it is getting more potent. They think it is benifiting from increased CO2, which usually doesn't affect most plant's growth quite as much.

But Djincs, I suppose, doesn't care if our magnificent planet turns into a land of poison ivy, rodents, and organisms that like to feed off oil. Go terraform another planet man..

Enjoy your new world:
5 / 5 (1) Jul 22, 2010
Read what I said "THEY THINK it is benifiting from increased CO2, which USUALLY doesn't affect most plant's growth QUITE AS MUCH."

I've experimented with CO2 increases with plants, there is little change usually. you can increase their growth much better with other resources. The story is fact, poison ivy is thriving and increased in toxicity this year. Why? they think it benifits more from CO2 than most plants, do they know it.. no.. more testing is needed.

Okay Djincs, I think we'll leave it there with your incomprehendable rambling and terrible grammer.. Granted, I've been guilty of bad spelling on this site in the past, but not that bad... You've alrady indicated you could care less if we cause a mass extinction event.. Why do you care so much about stopping us from preventing it? WHY? Why bother...IF you don't care, don't you have something better to do?
5 / 5 (1) Jul 22, 2010
Really? I thought deserts house more reptiles than mammals?

Anyway, I can't even understand what your saying, so I cannot argue with it... good tactic for you Sorry...

Just FYI-research yearly extinction rates, then tell me its normal.
1 / 5 (3) Jul 24, 2010
gwarth-in that case, you misread my comment. I wasn't saying we evolved in 100 years, I was saying that, when the planet was pristine, that is as good as it gets...We evolved with the planet.. now that link is disintegrating and most people do not understand how vital that link is to our survival.

The planet has never, ever, been "pristine". Where do you people learn such GARBAGE.

Thera. 20 extinction events in 550 million years. Tambora. Yellowstone. Deccan Traps. Siberian Traps. Bolide swarm at 35My. Krakatoa. mega-Tsunamis. Uplift of the Rocky and Sierra-Nevada Mountains. India slamming into Asia. Ice Ages. Hot House earth. Gamma Ray Bursts. Variable Star (Sol).

The planet has never been "pristine".

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.