Penguins: Sphenisciformes

The social penguin likes to live in groups of various sizes. They are rarely without each other's company and so have developed behaviors that allow them to live harmoniously for the most part. When they do fight, penguins use their flippers for hitting and their bills are used like swords.

Most penguins are somewhat monogamous (muh-NAH-guh-mus; have one mate), though they have been known to "divorce" and find new mates when a new breeding season begins. They engage in mating rituals and are able to find their mates in a crowd based on these rituals as well as by voice. Penguins are ready to breed between the ages of two and five years, with the female being ready somewhat earlier than the male.

Depending on the species, penguins lay one to three eggs. The incubation period lasts from thirty-three to sixty-four days, and chicks will hatch at the same time or within one day of each other. Once born, parents take turns caring for the chicks and hunting for food. The food-provider eats the prey, then regurgitates (re-GER-jih-tates; vomits) it for the chicks to eat. Once the chicks are old enough to eat and take care of themselves, parents continue to protect them.

Though adult penguins have no land predators, they do fall prey to sharks, leopard seals, sea lions, and killer whales. On land, chicks and eggs are often eaten by other birds.

In the wild, penguins can live up to twenty-five years.