The American pika (Ochotona princeps) is a small alpine mammal acting as a sentinel species for climate change. Unable to tolerate temperatures above 25°C for more than a few hours, pikas are retreating to higher elevations as warming drives them toward mountain summits.
As temperatures rise, pikas at low-elevation sites experience increasing heat stress events. Thermal death risk is real: pikas caught in exposed rocky slopes on warm days show respiratory distress and cessation of activity. Retreating to higher elevations reduces available habitat and increases isolation of already fragmented populations. The welfare impact is both acute (heat stress events) and chronic (reduced foraging time, smaller territories, nutritional stress from smaller haypiles). Shade from snowfields and deep talus provides microclimatic refugia that may buffer some populations, but these refugia are disappearing as snowpack declines.