Penguins spend the majority of their time in the water, but their nesting colonies are often located miles away from the water. Penguins tend to mate with their partner from the prior year's breeding season. The males stake out the territory, which could only be a few square yards. Nests are made in a wide variety of locations, depending on the species, and can be in a rock crevice or burrow, in the open with stick and grass, or on a bare patch of ground.
Usually all but the two largest species (the Emperor and King penguins) lay two eggs. The two large species lay only one egg. The Emperor penguin endures the worst breeding conditions of any bird in the world. After the female lays her egg during the dark Antarctic winter, she returns to the water to feed and regain her strength. While she is gone, the male incubates the egg on top of his feet. During this 64 day period, when the temperature can dip below 40°F (4°C), the male huddles with other males to stay warm and eats nothing but snow. When the chick is born, he feeds it with a milky substance he regurgitates. Both Emperor and King penguins have their young in the winter, so that they will become independent in the summer when food is abundant. Newborns of all species are born covered with a thick layer of brown or gray down. This down molts into feathers that look like those of the adult when the bird is a juvenile.