Pikas adapt to changing climate in surprising ways

Those who travel in the high country are familiar with the little, round, squeaking and incontrovertibly cute pika. What many people don’t know is that the pika is a critical “indicator” species that is helping biologists understand how many other mammals — from wolverines to moose — react to the changing climate.

Pikas are considered “harbingers of what is to come with climate change in mountain systems,” because they don’t migrate or hibernate, said Anna Chalfoun, assistant professor of zoology and physiology at the University of Wyoming’s Cooperative Fish and Wildlife Research Unit. They stay awake all winter under the talus, eating plants, shrubs and grasses. They forage all summer, stocking up food in what are called hay piles.

“They are one of the best species to look at to understand what is going to happen with alpine systems and climate change,” Chalfoun said. And several studies at the University of Wyoming are trying to do just that.

Concern for the pika

The U.S. Fish and Wildlife Services said pikas didn’t warrant protection under the Endangered Species Act in 2010. While the service determined climate change as the primary threat to the species, it also predicted that there is enough high-elevation habitat to ensure the animal’s long-term survival.

That decision doesn’t reflect biology, but insufficient information, Chalfoun said. The decision spurred biologists to start gathering more information on the small mammals.

One of Chalfoun’s graduate students, Leah Yandow, looked at pika populations in the Wind River and Bighorn mountains to try to determine what influences where pikas live. Scientists suspected pikas will migrate upslope to higher elevations as the climate warms, but Yandow found that was true only to a certain extent. Her findings suggest forage availability and other microhabitat features influence where pikas move, even as it gets hot. According to U.S. Fish and Wildlife Services, even brief exposures to temperatures warmer than 77.9 degrees Fahrenheit can kill the animals, which are extremely sensitive to temperature.

Another student, Embere Hall, a doctoral candidate at the university, looked at how temperature influences foraging behavior. She’s collected more than 7,000 videos showing 83 different pikas caching food in the last three summers.

Pikas respond unexpectedly

Hall’s preliminary findings show pikas foraging at night, which is interesting because the animals are considered diurnal, or active during the day. While more study is needed, the change in behavior could be a way to reduce heat stress on their bodies, Hall said.

She hopes agencies like Wyoming Game and Fish, which is a partner on the project, will use her findings when revising state wildlife action plans. The data gives a better understanding of what types of habitat might need protection. Scientists thought pikas would move to higher elevations as temperatures increased, but in many cases that hasn’t happened.

“We’ve started to see there are populations that aren’t following our models,” Hall said. The data allows researchers to look at why there are pikas in places they weren’t expected, and whether those animals survive in those areas long-term.

“But in a broader context, understanding the extent of which climate-sensitive species have the capacity to alter behavior gives us a sense of how we can proceed in an uncertain future,” she said.

It allows scientists to think about stop-gap solutions to help climate-sensitive species until evolutionary changes in the animals might catch up. If a temperature sensitive species such as the pika can exhibit flexible behavior changes, other animals might also be able to adapt, such as wolverines which live in a similar high-elevation environment and are active year-round. The findings could also relate to moose, which are sensitive to climate change and summer heat stress, Hall said.

There are other factors that will influence pika survival, such as disease and predation, that haven’t yet been studied.

Pikas are “adorable,” Chalfoun said. “It tugs at the heart strings, but they also happen to be fascinatingly interesting biologically, and unique.”

Watch this clip of a pika foraging: