英語聽力：從南極到北極 2

The penguins stay when all other creatures have fled because each guards a treasure—a single egg rested on the top of its feet and kept warm beneath the downy bulge of its stomach.

There is no food and no water for them. And they will not see the sun again for four months. Surely, no greater ordeal is faced by any animal.

As the sun departs from the Antarctic, it lightens the skies in the far north. It’s March and light returns to the high Arctic, sweeping away four months’ of darkness.

A polar bear stirs. She has been in her den the whole winter. Her emergence marks the beginning of spring. After months of confinement underground, she toboggans down the slope, perhaps to clean her fur, perhaps for sheer joy.

Her cubs gaze out of their bright new world for the very first time. The female calls them , but this steep slope is not the easiest place to take your first steps.