I have studied pikas, little cousins of rabbits, for over 50 years and I never tire of looking at them. These tailless, egg-shaped fluff balls live mainly in cool mountainous environments in piles of broken rock called talus.
During the summer, observers can watch pikas diligently gathering caches of grass and leaves into hay bales that serve as a food supply all winter. Their light brown coats blend well with their environment, so they are easiest to spot when perched on prominent rocks warning other pikas of their presence.
When fellow hikers see me observing pikas in California’s Sierra Nevada, they often tell me they’ve read that these animals are becoming extinct. I’ve collected a bunch of press releases saying just that. But based on my recent research and an extensive review of more than 100 peer-reviewed studies, I think this interpretation is misleading.
Limited by climate
As I showed in my early research, the biology of pikas suggests that they are likely affected by a warming climate. Most importantly, their normal body temperature is high, which puts them at risk of overheating when operating in warm environments. When temperatures are warm, pikas retreat to the much cooler depths of their talus habitats.
Temperature also plays a role in pikas’ ability to move from place to place. Warm weather inhibits their movement, while cooler temperatures allow them to more freely colonize new habitats.
A little ancient history is educational here. Pikas originally came to North America from Asia and spread across the continent about five million years ago, during colder times. Their remains have been found in caves in the Appalachians and in the Mojave Desert – locations where pikas no longer live.
American pikas live primarily in alpine and subalpine mountain regions extending south of central British Columbia and Alberta into the Rocky Mountains of New Mexico and the Sierra Nevada of California. Andrew Smith, CC BY-ND
As the global climate warmed, pika populations retreated to the high mountains of the western US and Canada. Today, they occupy most of the available talus habitat in these areas – evidence that challenges the story of pikas-on-the-brink.
For example, in recent studies, pikas were found at 98% of 109 suitable sites in Colorado and 98% of 329 sites in the central Sierra Nevada. A study of historic pika sites in Lassen, Yosemite, Kings Canyon, and Sequoia National Parks in California found no evidence that pikas were moving to new locations or greater elevations as a result of climate change.
Pikas in warm environments
In contrast, most of the sites where researchers believe pikas have disappeared are small, isolated, and often compromised by human activities, such as livestock grazing. These sites are generally lower and warmer than sites in the core Pikas range.
Many of these areas are in the Great Basin – a large desert area that encompasses most of Nevada and parts of Utah, Idaho, Wyoming, Oregon, and California. A series of investigations into a small number of marginal Great Basin sites previously occupied by pikas has disproportionately contributed to the story that pikas is likely to be in danger.
To investigate the big picture in this region, I worked with state and federal officials on a 2017 study that identified 3,250 pika habitat location records. Pikas were present in 2,378 sites, not found in 89 sites where they had been seen as recently as 2005, and absent from 774 sites that showed only old signs of pika occupation.
The extinct and old sites had the same temperature and precipitation ranges as sites where pikas were still present. This suggests that non-climatic factors may have caused the disappearance of pikas from the vacant sites.
Pikas have disappeared from some parts of the Great Basin, but climate change may not have been the cause. Kmusser / Wikipedia, CC BY-S
Pikas are still present in other remarkably hot places, such as the ghost town of Bodie, California, the nearby Mono Craters, and Idaho’s Craters of the Moon National Monument. In these locations, pikas retreat to the cool corners of their talus habitat during the hottest part of the day and often forage at night.
In my research, I also found that pikas were much less active and made far fewer calls in these low-lying locations compared to high-altitude pika populations. In low-lying locations, pikas consumed a varied diet of Great Basin plants, such as big sagebrush and bitterbrush, which was markedly different from the plants they ate in high-altitude locations. Some even failed to build their characteristic large hay bales.
Another atypical pika population lives near sea level in Oregon’s Columbia River Gorge. Here, too, they have adapted well to a completely different habitat, surviving all year round on a diet consisting mainly of moss. They defend each pika’s smallest territories, and when the weather gets hot they just go off the talus and hang out in the shade of the nearby forest.
A future for Pika’s
Based on my review of dozens of studies, pike populations appear to be safe in their core region – the mountains of western North America with a large and reasonably well-connected talus habitat. In these areas, they can move from one habitat to another without having to pass through areas that are dangerously hot to them.
The fact that pikas have also adapted to some marginal, hot environments suggests to me that they are more resilient to climate change than many previous studies have concluded. Most species show losses near the edges of their geographic range, simply because individual animals in those zones live in conditions that are not ideal for them. This does not mean that they are dying out.
Climate change is the most critical problem facing the world today, so it is especially important for scientists to accurately communicate about it with the public. In my opinion, the fact that pikas interact with and change their behavior in response to changing circumstances is encouraging news for future naturalists who will observe one of nature’s most charismatic mammals.
Andrew Smith is a professor emeritus of life sciences at Arizona State University.
Disclosure Statement: Andrew Smith does not work for, consult, own stock or receive funding from any company or organization that would benefit from this article, and has not disclosed any relevant affiliations outside of his academic appointment.
Reposted with permission from The Conversation.
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