A pika in its talus home. Photo: Karunakar Rayker
When Chris Ray got started studying pika, she could not have anticipated that these small rabbit relatives would one day become a poster child for climate change, which the species has, partly through the efforts of the Center for Biological Diversity to get them on the Endangered Species List. Because pika live mostly in alpine environments, are sensitive to temperature, and are poor dispersers, they are perhaps particularly vulnerable to increasing temperatures. In late August 2011 I joined Ray, a research associate at the University of Colorado, Boulder, at Emerald Lake in Hyalite Canyon, near Bozeman, Montana, where she has studied pika every year for the past 21 years.
Pika live in talus slopes, which are gullies of rock making gray stripes down the otherwise evergreen-covered rises around the canyon. Ray is gone from her tent at the campsite before 6:30 each morning, carrying equipment to the slopes, leaving her husband and her four-year-old son asleep. By 7:30 I head off with two young research assistants to join her. We call in to Ray and she gives us GPS points for her location. The first morning I go with them, it takes us a full hour to reach her. The rocks are piled up on each other and unsteady. The angle is steep. I'm rather obsessed with the distinct possibility of breaking my leg, and exhausted when we reach our destination, before the day's work, which Ray will continue without break until six or seven p.m., has even begun.
Ray collects data about pika presence and absence at 100 control points in a study area that is overall two kilometers by three kilometers. She also tracks temperature throughout the year using “iButton” data loggers dispersed around the talus. Using four different ear positions and five colors of tags, Ray ear-tags pika annually—this summer she tagged 45—thus recognizing their individuality, by which she can keep track of their mortality. To date she has tagged and tracked 625 unique pika; she has observed some individuals as many as nine years in a row.
Pika are saucy little bunnies, and they spend all summer "making hay while the sun shines," because they don't hibernate. One of the main things they do is cache "haypiles" in the rocks. That means they race around with flowers in their mouths much of the time. These little bunnies take the Goldilocks syndrome very far, with finely tuned sensitivity to hot and cold. While other animals have natural thermoregulatory responses to temperature fluctuations, the pika have to deal with these behaviorally. They don't hibernate, so they need a very insulating fur coat, which is good in winter, but in the summer it becomes a problem. To help deal with the winter chill, the resting body temperature of a pika is near its lethal maximum, which is what makes them intolerant to summer heat. Pika have to be out working hard all summer to collect enough food to last them all winter, and during the hottest part of summer days they take refuge in the spaces under the rocks in the talus.
While many have written the end story for pika by pointing upward and finding nowhere for them to go as the climate warms, Ray has in the back of her mind another idea. She wonders if what makes pika so sensitive and evidently vulnerable will wind up being their salvation. “Pikas are so good at finding the microclimate they need that they may avoid climate change altogether,” she says. Although that depends on a fairly stable mountain ecosystem.