Macaroni penguins eat mostly krill, supplemented by some squid and small amounts of fish and flat-bodied crustaceans. Some populations migrate long distances to the Indian Ocean to take advantage of large krill and crustacean populations there. During the breeding season, macaroni penguins fast for up to 40 days.
Macaroni penguins live along the rocky coastlines and cliffs of Antarctica and south of South America and Africa, in groups of up to 2,500,000. They breed near the Atlantic Ocean in October and, in the mud and gravel among the rocks, lay their eggs in early November. Their hugely populated breeding grounds produce smells detectable from miles away.