Penguins can bite, but biting is only one of the jobs their beaks do. Most of the time, the beak is catching fish, preening feathers, courting a mate, guarding eggs, feeding chicks, or giving a final defensive warning.
Many penguin parents raise young in shifts: one guards the egg or chick while the other goes to sea for food. They keep chicks warm, regurgitate meals, and in some species use creches as chicks grow.
Penguin courtship begins with posture, calls, and stones, but the real test comes in incubation shifts and chick-rearing; under the romantic surface is a cooperative system that cannot afford mistakes.