One of the most contentious climate change debates is whether wildlife will adapt or die when threatened by global warming, and what humans should do to save them. Now a new study suggests that one of the critters most at risk from climate change could indeed survive by adapting a rather unappetizing diet.
An impossibly cute member of the rabbit family, the furry pika lives on rocky slopes of the mountains of the North American west. It survives frigid winters by maintaining a high body temperature. But since it cannot control its internal thermometer, the pika is extremely vulnerable to rising temperatures as climate change accelerates. In the summer, the pika can die if its body temperature increases by as little as 3 degrees Celsius (5.4 degrees F).
As some populations have disappeared from lower elevations and others have migrated toward mountain tops, environmentalists have fought (so far unsuccessfully) to have the pika listed by US state and federal governments as endangered. That in turn could obligate governments to stop carbon-spewing industrial development harmful to the pika.
When California authorities on May 22 rejected for the second time a petition to protect the pika, they cited the possibility that the pika could adapt to a warmer world. A study from the University of Utah published this past week (paywall) supports that argument. Researchers studied the dining habits of a colony of pikas that for a century have lived at near sea level in the Columbia River Gorge in Oregon and Washington State. That’s a far lower and warmer elevation than where most pikas are found and researchers wanted to know how they survive.
The answer: moss.
The pikas observed between 2011 and 2012 depend on moss for about 60% of their diet. Thick carpets of the vegetation cover rock piles, called talus, which pikas nest in. Talus provides both cover from predators as pikas move about and a ready source of pika chow. That means the pikas don’t have to venture out from the cool talus into the potentially deadly sun as much in the summer to forage for food to store for the coming winter. (The moss also helps the pika beat the heat by keeping their rock piles cooler.)
There’s just one problem. Moss is extremely low in nutrients, which is why mountain pikas don’t each much of it. The Columbia River Gorge pikas, though, have a solution. Microbes in their guts ferment the fiber in moss to create more nitrogen and thus nutrients. When pikas defecate, they eat the resulting “caecal pellets” (a behavior common in the rabbit family). “Caecal pellets were by far the most nutritious food item tested,” the study states.
“It’s not clear whether this will have any bearing on other populations of pikas in response to climate change, but it certainly suggests that they are a little more adaptable than we originally gave them credit for, particularly in terms of what they can eat,” Johanna Varner, a PhD student and a lead author of the study, told Quartz in an email.