No land animal, and I think no sea animals either, stay in the antarctic during winter - except for one: The emperor penguin. These penguins not only stay there, but their prolonged stay involves 4 months of harsh winter, averaging -70$^o$C, no sunlight and no food for that period of time. And if that wasn't enough, then it's during that time that the emperor penguin male incubates the egg alone, left by his female mate. The male emperor penguins gather together to endure the antarctic winter.
My question thus becomes very obvious: Why does the emperor penguin stay in Antarctica during winter at all, and moreover, breed there during that time and incubates a precious egg in the harshest conditions on earth, while all other animals flee for their lives?