Unlike the Adelie penguin who breeds during the summer months, the Emperor penguin breeds during the winter months. The female lays only one egg per season. If something was to happen to the egg, she will have to wait till the next season.
Once she lays the egg, she will pass it over to the male. This is a delicate transition because if the male does not scoop it up quick enough, the egg will freeze. When the egg has been handed over, the female will go in search of open ocean water (that has not been frozen over) to hunt prey. Sometimes, she may have to travel up to 50 miles.
The male will keep the egg warm during the incubation period by balancing it on his feet and covering it with a warm fold of feathered skin called a brood pouch. During this time, the male mostly sleeps and will not feed. By the time the egg hatches (about 2 months), the male Emperor will lose about 1/3 to 1/2 of his body weight.
If the female does not return by the time the chick hatches, the male can produce a white secretion ("milk") from a gland in his esophagus to feed the chick. However, this is only temporary. If she does not return soon, he will have to abandon the chick to save his own life.
When the mother comes back, she will have a full belly to care for her newly-hatched chick. She must continue keeping the chick warm with her brood pouch. If she doesn't, the chick can die within minutes. By the time the ice at the breeding ground begins to break from the warmer temperatures, the young penguins are ready to swim and catch their own food.