National Geographic News
Photo of an American pika in Alberta, Canada.

The American pika is adapting to a warming environment by eating papery, nutrient-poor mosses.

Photograph by James Hager/Robert Harding/Corbis

Carrie Arnold

for National Geographic

Published December 19, 2013

As the planet continues to warm, conservation biologists worry about the future of species that depend on the cold, such as the furry pikas that live in mountainous areas of North America, Europe, and Asia. But American pikas (Ochotona princeps) may be able to survive a warming planet thanks to a most unusual food source.

A new study found that pikas living at lower elevations seem to thrive in part by eating nutrient-poor mosses, which suggests that these animals may be able to adapt their behavior to a warming planet.

Pikas are known for their ability to live in frigid, alpine areas, and these furry critters are a common sight on the rocky slopes of Mount Hood, outside of Portland, Oregon. Part of the lagomorph order, which includes rabbits and hares, the American pika is the size of a large mouse and looks like a miniature guinea pig.

The pika has a very high metabolism, which enables it to produce large amounts of body heat. Its large belly, short limbs, small ears, and absent tail give it an almost spherical shape that helps it conserve this body heat, as does its thick layer of gray-brown fur. The pika is so good at conserving heat that spending more than two days living at temperatures above 78°F (25.5°C) can kill it.

It's why University of Utah Ph.D. student Johanna Varner was so surprised to hear reports of pikas living in the Columbia River Gorge, a low-lying area not far from Mount Hood. The environment in the gorge is totally different from what the pikas were used to on Mount Hood itself.

On the mountain, the pikas had only three months without snow—a short summer period in which the roly-poly furballs made a mad dash to collect as many plants, grasses, and shrubs as they could to create caches of food known as haypiles to nibble on throughout the long winter. The Columbia River Gorge, on the other hand, is covered in snow for less than three weeks per year. Varner wanted to know how these pikas lived and what they ate.

She trekked from Utah to Oregon to conduct detailed studies of the pikas on Mount Hood and in the gorge. In the Journal of Mammalogy, Varner and a colleague note that they took turns at two-hour binocular shifts, observing everything that adult pikas ate. Unlike their counterparts on Mount Hood, the Columbia Gorge pikas consumed a diet of moss. This surprised Varner even more because mosses are not a high-quality food source.

"Mammals typically can't eat large amounts of moss because it's a low-quality food. It's about 80 percent fiber, so it's kind of the consistency of eating paper," Varner said.

Eats, Poops, and Leaves

Helping the pikas extract maximum nutrition from these mosses is a habit called coprophagia, which "is a fancy way of saying they eat their own poop," Varner says.

Although the pika produces some fecal pellets that are small and hard, it also produces fecal matter known as caecal pellets, which are larger and wetter than other poop. The pikas then reingest the caecal pellets, which are a surprisingly nutritious mix of partially digested moss and gut microbes. Unlike the pika, the microbes can directly digest the moss, which enables the pika to extract more nutrients.

"This is about six times more nutritious than the moss is," Varner said. "It's the same idea as a cow chewing its cud, only the pikas use the other end."

Although the moss might not provide the quality of nutrients that grasses and wildflowers provide—even when the pikas eat their fecal leftovers—Varner noted that the low-altitude pikas did not appear to expend nearly as much energy gathering plants for their haypiles as the pikas on Mount Hood did. This energy savings might help to offset the reduced nutrients and energy in the moss.

In 2010, the U.S. Fish and Wildlife Service declared that American pikas were not yet considered endangered and declined to add them to the endangered species list. This upset many environmentalists, who believe that warming temperatures are placing the pikas at risk.

Varner says that her work doesn't imply that climate change won't ever harm pikas, but it does indicate that they are much more flexible in their behaviors than previously thought. She also notes that it's still currently unclear whether other pika species share this behavioral flexibility and cautions against assuming that all pika species will respond this way to climate change.

28 comments
David Seabaugh
David Seabaugh

Fascinating animals. I really enjoyed the article. However, I was skeptical of the basic premise that the animals were "adapting to a warming environment" so I ran a quick check through the national climate data center ncdc.noaa.gov and discovered that the average annual temperatures for Mount Hood have decreased by -0.3 degrees F during the period 1973 to 2013. Therefore, one can only conclude that while warming may be occurring, it is certainly not occurring in the Mount Hood area.

Ann Holmes
Ann Holmes

what a world we are doing in our everyday gestures

Allan Williams
Allan Williams

an interesting coincidence that PICA, with a "C", means "the tendency or craving to eat substances other than normal food . . ."

jerry wexler
jerry wexler

Ridiculous article. Has nothing to do with climate change. They just love to go the "global warming" route whenever they can just for the hell of it.  

Steve Henrich
Steve Henrich

Helping the pikas extract maximum nutrition from these mosses is a habit called coprophagia, which "is a fancy way of saying they eat their own poop," Varner says.



So then,... hehe..... I could get away with saying that so and so is a `coprophagist?   Yesss!!!  Right on!!!!  I like it!!! hahahaha!!!

Mark Meyer
Mark Meyer

The first sentence is ignorant.  The planet has been cooling for the last 13 years.

Richmond Acosta
Richmond Acosta

@Mark Meyer The Philippines too, we are experiencing some of the hottests months in many years. In fact, right now, the weather here should be around 20 degrees celsius but it is a hot 30 degreees. Not only this, for the past 5 years we were having the worst storms and monsoon rains. I am sure you are familiar with Typhoon Haiyan, well Haiyan was not the first strong typhoon to ravage us in the past five years, we have 3 typhoons almost as strong as him every year since 2008.

Brian Hase
Brian Hase

@Mark Meyer Please let the ignorant Pikas know about this Mark.  They are starting to eat their own feces to survive the heat, when they should know that the planet has been cooling for the last 13 years.  Aren't they going to feel silly for resorting to such a means to survive...... or..... should Mark become enlightened a little bit from his furry little buddies.  Listen to your mother nature Mark

Vicki Lipski
Vicki Lipski

@Mark Meyer Hi Mark - Michael is right; warming has slowed, but it certainly has not been reversed.  Not only we, but Australians, the Japanese, and the Chinese experienced record-setting temperatures this year.  The oceans have absorbed enough warmth to warp fish brains (!), and we'd be remiss in forgetting the Yarnell fire in Arizona, not to mention California's third-biggest wildfire on record.  As for ice in the Arctic ....

Michael Jones
Michael Jones

@Mark Meyer Perhaps if the planet was really cooling we would not witness the warmest November on record (since 1880) and the 37th consecutive November which was warmer. Nor would we see the 5th warmest year likely to be for 2013. Some "cooling", Mark.

jerry wexler
jerry wexler

@Kenny Wood @jerry wexler Ha, attack the commenter because you have no come back to the comment. Why not just give it a shot Kenny and go for it? Explain why you feel my comment is ridiculous. Pick up where the article connects global warming with rodents eating moss. Please. I dare you. 

Marty Johnson
Marty Johnson

@Kenny Wood @jerry wexler 

This is a cult site now for the new age-global warming-is-only-caused-by-capitalist governments-wealth-redistribution-anti-capitalist-crowd, who need to save the world!

Beef Industry- Cows Farting
Cars- (although infinitely cleaner emissions than 30 years ago) exhaust
Any private plant farm- too much CO2

I remember a few years back there was a huge billboard off I-75 that stated that pet feces were getting into our groundwater and making us sick. People I worked with ate it up as gospel. 
Forget the billions of wild animals who defecate constantly every hour, every day.

Sorry, I believe there is some warming going on for the time being, but when the only cause is blamed on right wing governments and the solution is ONLY to empower more left wing governments and redistribute wealth to stop the earth from warming, I say BS.

Governments murdered 100s of millions in the 20th century over their need to control others. I see the same thing slowly returning today.

I am all for keeping our water, land, and air clean. I believe there are some guilty companies who do cause harm. I also believe that governments do more harm to the world than any company.

We just came out of an Ice Age and the earth started warming 10's of thousands of years before civilizations began popping up.

But this subject is more about the egos of a few who think they have the power to 'save the world' the same way a co-dependent tries to save addicts.

So sick of seeing people trying to shut others up if they disagree- once someone says that the debate is over on any scientific subject, I know that person is not a real scientist and has a political agenda.

Just because you silence someone does not mean you changed their mind.

David Seabaugh
David Seabaugh

@Richmond Acosta Do you ever research facts for yourself? I've never seen anyone be wrong all the time. Even a blind squirrel finds a nut every once in a while. Average temperatures are not any warmer in the Philippines now than they were a century ago. (Look it up!) Climate history didn't start when you were born. Also, four of the worst typhoons to hit the Philippines occurred in 1881, 1867, 1897, and 1981. The 1881 cyclone was stronger than any that have occurred in the past ten years. Please quit posting your faith based statements. Those of us who value evidence, reason and facts are getting tired of having to constantly correct your lunatic ravings every time an article alludes to your Global Warming god.

Don Reed
Don Reed

@Brian Hase you forgot to mention the fact that these pikas are outside their normal habitat zone. You're mistaken in your assumption that this is normal behavior for the species. 

Ian Maxwell
Ian Maxwell

@Vicki Lipski@Mark MeyerYes. Each year sees higher & higher record temperatures here in Australia. I work in horticulture which is an industry structured around the seasons to the nth degree. We are very much aware of normal seasonal variations. The industry is built on centuries of coping with them, but what we are getting lately is well outside normal. Not only are our dams bone dry for the first time in living memory, there were issues germinating a heap of crops because of the mildew & other biological threats that came with the last, abnormally warm winter. Pests like aphids attacking citrus & so on were rife thru the spring. I imagine their numbers were up because of the lack of culling over the practically non-existent winter. I don't know if our experiences are a broader indication of anything or not, but they are not reassuring.

David Seabaugh
David Seabaugh

@Marty Johnson I wholeheartedly agree! Isn't it interesting that all of the warming skeptics' arguments are well thought out and always backed by evidence and reason while the global warming kool-aid drinkers arguments' amount to nothing more than name calling?

Please see my comment above offering indisputable evidence that temperatures have DECREASED in the Mt. Hood area. Thereby invalidating the entire premise of the article.

Brian Hase
Brian Hase

@Don Reed@Brian Hase precisely Don.  They are moving outside of their normal habitat and adapting behavior to survive in a changing environment.  They see the change and need to adapt, why can't we?  Statistics, like the planet cooling for the last 13 years, can come biased from any group wanting to skew the results towards their cause (may be true, but is it cooling at the rate nature intended, or influenced by man).  Nature though, and the Pikas, hold no bias.  When nature speaks to adapt to a change, I listen.  I simply hope others do as well

David Seabaugh
David Seabaugh

@Ian Maxwell No offense, but you have a simplistic understanding of the climate change debate. No one is arguing that there is no climate change. It's your side that uses antidotal evidence when it suits your agenda. We are arguing that there is no evidence that climate change is caused by man. Climate change has always occurred ( please see little ice age, warmer temperatures during Roman times than now, worldwide warming 10000 yrs ago etc., etc.) Also, it's disingenuous and intellectually lazy to assert that every weather event is proof of man caused warming. By the way, since you (very bravely) brought climate change models up, please forgive me for pointing out that they have all been incorrect as predictors of future temps. Did you miss the email scandal when your comrades tried to cover up the abject failure of the predictive models?

Ian Maxwell
Ian Maxwell

@Don Reed@Michael JonesWhich is part of what has been predicted in climate change models since at least Lovelock. No offense, but u have a simplistic understanding of climate change which was probably instilled more by the ravings of paid media pundits than any actual effort to learn & understand the science involved. The average global temperature is rising & over-compensating, natural responses such as the snow u mention in Cairo have always been expected. However u look at it, snow in the desert is a climate change. 

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