Egg

Hatching a plan for survival isn't always easy in the wild. And how animals lay, protect, and even use each other's eggs as a food source help reveal the life cycle of the natural world.

Eggs come in all shapes and sizes. The ostrich's is the largest, but some are so small, you need a microscope to spot them.

Animals hide them and disguise them in smart and surprising ways, too.

Some abandon their eggs, while others protect them fiercely and carry them wherever they go.

There are as many kinds of eggs as there are animals that depend on them, because in the animal kingdom, the fight for survival begins with the simple, but extraordinary, egg.