American Pika

It has a dense insulating coat and an unusually high resting body temperature adapted for surviving the cold, high-altitude environments it lives in, but these same adaptations make it extremely poor at shedding excess heat. Direct exposure to summer sun and temperatures only moderately warm by human standards, sometimes as low as the mid-20s Celsius, can cause fatal heat stress within just a few hours if the pika cannot retreat into cool shade or a rocky crevice. This narrow thermal tolerance is a central reason the species is considered particularly vulnerable to a warming climate compared to many other mammals.

Unlike many mountain mammals that survive winter by hibernating, the pika remains active year-round beneath the snowpack, which means it needs a reliable food supply stored in advance rather than relying on fat reserves alone. During the short alpine summer, it spends much of its time cutting grasses and wildflowers, carrying them back to a favoured spot near its rocky den, and spreading them out to dry in the sun before stacking the cured plant material into a haypile, sometimes amounting to many kilograms per individual, which it then feeds on steadily throughout the long, snow-covered winter months.

Because it depends on cool, rocky alpine habitat and cannot tolerate sustained heat, it is unusually sensitive to even modest increases in average temperature, and researchers have documented pika populations disappearing entirely from a number of low-elevation and range-edge sites over recent decades as conditions there have warmed. Since the pika cannot simply move to a cooler climate the way a more mobile or heat-tolerant species might, and since suitable cool alpine habitat is finite and shrinking upslope as temperatures rise, scientists studying mountain ecosystems treat local pika population trends as one practical, observable indicator of how a changing climate is already affecting high-elevation wildlife.

Despite its small, rounded, almost rodent-like appearance, it belongs to the order Lagomorpha, the same broader group that includes rabbits and hares, rather than to the rodents such as squirrels or mice that it might be casually mistaken for. Lagomorphs share several distinguishing features not found in true rodents, including a particular arrangement of teeth in the upper jaw and a shared digestive strategy involving reingestion of certain droppings to extract additional nutrients from tough plant material, a practice pikas also perform. Pikas represent one of the two main living lagomorph families, distinct from the larger, longer-eared rabbits and hares.