A diminutive creature that struggles with warmer temperatures brought on by climate change will not receive Endangered Species Act protection for its predicament, the Obama administration has decided in a move that brought quick condemnation from some corners.

The American pika, a diminutive relative of the rabbit that looks more like a mouse, lives in the mountains in rocky slopes. You often can hear their high-pitched squeaks as you hike in the high country of Grand Teton, Yosemite, and Glacier national parks, just to name three where pikas are found. Here in boulder fields and talus slopes the pikas, which weigh between 4 and 6 ounces, forage on forbes and wildflowers, burying caches within the rock piles to help them through the winters.

Unfortunately, the thick coats that help the pikas survive the cold winters at these elevations are extremely warm in summer, and researchers say temperatures of 78 degrees Fahrenheit can be deadly. And with warming temperatures moving ever higher, pikas are running out of cooler places to go. Erik Beever of the U.S. Geological Survey and colleagues have traced the pikas' movement to higher elevations in the Great Basin mountains of eastern Nevada. In Nevada's Ruby Mountains, for example, they found that pikas, recorded at 7,792 feet in 1956, were rare below 9,000 feet by the 1990s. "At the current rate, pikas could pop off the top of the highest peaks in the Basin within 100 years," Beever and his colleagues reported.

On Thursday, the Interior Department declined to list the pika (see attachment) under the ESA, saying evidence of the species' status was spotty: some areas, such as lower elevations in Yosemite, were losing pika populations, but other areas, such as in the mountains surrounding Bodie, California, and the "Sierra Nevada and southwestern Great Basin," contained populations that are doing well and which "show little evidence of extirpation or decline."

Nevertheless, the Center for Biological Diversity, which sought the listing, maintains that there's ample evidence that the species is in danger of becoming extinct by the end of the century due to warming temperatures

“This is a political decision that ignores science and the law,” said Shaye Wolf, a biologist with the center. “Scientific studies clearly show that the pika is disappearing from the American West due to climate change and needs the immediate protections of the Endangered Species Act to help prevent its extinction. The Interior Department has chosen to sit on its hands instead of taking meaningful action to protect our nation’s wildlife from climate change.”

At Earthjustice, a legal group that brought the lawsuit forcing the Interior Department to act on a petition asking for the listing, Greg Loarie maintained that "We've already lost almost half of the pikas that once inhabited the Great Basin, and scientists tell us that pikas will be gone from 80 percent of their entire range in the United States by the end of century. To conclude that this species is not threatened by climate change is an impossible gamble that we can't afford."

According to the center, "rising summer temperatures threaten pikas with heat stress and reduce their ability to gather food and move to new areas, while diminished snowpack in winter leaves them vulnerable to cold snaps."

A listing under the Endangered Species Act would have benefited the pika by requiring land-management agencies to take the small mammal and its habitat requirements into consideration when making decisions that could impact the habitat, such as alpine grazing that could reduce vegetation for the pika, Ms. Wolf said Friday. It also would require the U.S. Fish and Wildlife Service to develop a recovery plan for the species.

"When a species is listed, federal agencies have to ensure that their activities don’t further push a listed species towards extinction. If that activity has the potential to impact, to jeopardize that listed species, then the federal agency would have to take feasible steps to reduce those impacts," she said.

Mr. Loarie added that with such a listing, permitting agencies would have to take the pika into consideration when confronted by projects that could contribute to global warming.

According to Ms. Wolf's organization, "more than a third of documented pika populations in the Great Basin mountains of Nevada and southern Oregon have gone extinct in the past century amid rising temperatures. Two separate studies have found that climate change will eliminate suitable habitat and push pikas toward extinction throughout much of the western United States in this century if greenhouse gas emissions are not drastically reduced."

In a January 2010 article in the journal BioScience, pika scientists highlighted the pika’s vulnerability to climate change:

“There’s enough evidence to say that pikas are going to be among the first mammals to be adversely affected by climate change.”

“The problem with global warming is that if [pikas] lose [their] snowpack, which provides insulation in winter, they freeze to death, and if the ambient air temperature heats up too much in summer, then they fry. That’s the challenge. . . . They’re already at the top of the mountain. If you heat it up substantially, there’s no place for them to go.”

Back in December the Endangered Species Coalition listed the pika as one of 10 species most threatened by climate change. Also in December, Grand Teton officials announced research was under way in their park to better gauge the climate's impact on pikas.

In addition to Glacier, Yosemite, and Grand Teton national parks, pika can be found in Crater Lake, Yellowstone, Rocky Mountain, Mount Rainier, Sequoia, and Kings Canyon national parks, according to the World Wildlife Fund.