In settling a lawsuit with an environmental group, the U.S. Fish and Wildlife Service agreed to quickly consider whether to protect an alpine rabbit relative known as the American pika because of warming temperatures and habitat loss.
The federal agency said it would make a decision by May on whether protection is warranted.
The Center for Biological Diversity had sued in August to protect the so-called "boulder bunny" under the federal Endangered Species Act.
The center alleges that the pika is losing its cold, high-altitude habitat because of global warming.
"Adapted to cold alpine conditions, pikas are intolerant of high temperatures and can die from overheating when exposed to temperatures as low as 78 degrees Fahrenheit for just a few hours," the center said in a statement.
It added that pika populations have been moving uphill as temperatures warm.
"As temperatures rise, pika populations at lower elevations are being driven to extinction, pushing pikas further upslope until they have nowhere left to go," said Shaye Wolf, a biologist with the center.
More than a third of pika populations in Nevada and Oregon's Great Basin mountains have gone extinct in the past century, the center added, and the rest there are found an average of 900 feet farther upslope.