consider the caribou

摘要

IN THE WILD, TIMING IS EVERYTHING: MILLIONS OF YEARS OF EVOLUTION have maldespecies dependent on seasonal cues. In parts of North America, fall's cooler weather signals some birds to fly south and avoid Jack Frost's chill; meanwhile, shifts in both temperature and sunlight tell maple trees to shed their leaves. As Earth warms, some creatures are rapidly recalibrating their clocks. But others, such as caribou in Greenland, have stuck to the same old timetable. For them, the results are catastrophic.