With button-brown eyes, striped cheeks and a bushy orange-black tail, the Inyo chipmunk has darted among the gnarled pines of the Sierra Nevada for centuries.
But it has apparently vanished.
"We have not been able to find it anywhere," said James Patton, a retired UC Berkeley professor of zoology who has scoured parts of the high Sierra over the past two years in search of the elusive species.
No one knows why — or when — the species vanished. There is talk about air pollution and competition from other chipmunk species. But most of the speculation centers on climate change, which has brought warming temperatures, earlier snowmelt and changing forest conditions to the region over the past century.
"Something is going on," said Patton, whose previous research helped show that the abundance and distribution of other chipmunks in the Sierra has changed, sometimes dramatically, as the range has warmed.
There is still a chance, of course, that some of the missing Inyo chipmunks may turn up somewhere. But Patton, one of North America's leading mammalogists, is not optimistic.
"As near as we can tell, it is gone from the Sierra," he said.
If true, it would mark the first time in many decades that a mammal has disappeared from the Sierra. And while Inyo chipmunks can still be found in the nearby White Mountains, their exit from the Sierra has struck a note of concern.
"Who knows where they are going to disappear next?" said David Graber, chief scientist for the Pacific West region of the National Park Service.
"The ecosystem of the Sierra Nevada is now more impoverished because it's lost this species."
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