A herd of musk oxen hunkers down to wait out a snowstorm. When the weather gets foul, their strategy is to stay and cope. Unlike Arctic caribou, musk oxen do not migrate seasonally. Instead, their squat, woolly bodies limit heat loss, even when temperatures plunge below -40°F (-40°C).
Extreme shifts in climate, however, can distress musk oxen. But this too is part of their survival strategy. Study of ancient DNA reveals that over many millennia, musk ox populations have undergone repeated boom and bust cycles in response to climate fluctuations. Being able to rebound after population collapses may have helped musk oxen survive the end of the Ice Age when most other large mammals, like woolly mammoths, died out.