Staples

• Penguins eat krill, fish and squid as they are available. Penguins that live closer to the equator, such as the fairy penguin, consume more fish. Penguins that live closer to the pole, like the emperor penguin, eat more krill and squid. Some species, like the Fiordland crested penguin, also consume cuttlefish, shrimp and other crustaceans.
  
  

Hunting

• Penguins may spend as much as 3/4 of their lives in the water, and do all their hunting there. Penguins hunt primarily by sight. They spend most of their time in shallow water--within 60 feet of the ocean's surface--and catch their prey in their beaks. Prey animals are swallowed whole as the penguin swims. On some occasions, when a penguin catches a fish too large to eat while swimming, it will drag it to shore, then swallow it.
  
  

Juveniles

• Penguins breed and nest on land, hatching small, fluffy chicks that can't immediately catch their own food. Juvenile penguins consume food that their parents regurgitate for them, either directly into the chick's mouth, or onto the ground for the chick to pick up. The parents stop feeding the chick right before it grows its adult plumage.
  
  

Fasting

• All species of penguins go through annual fasts, both during the breeding season and their annual molting periods. Before these fasts, penguins spend time eating more fish and krill to build up a protective layer of fat. Some penguins fast through the entire period of courtship, nesting and egg incubation. Molting penguins must fast because they are unable to survive the cold water without their feathers.
  
  

Expert Insight

• Environmental factors may change what penguins eat. According to National Geographic, whaling may have triggered a shift in the diet of the Adelie penguin over the past 200 years. These penguins originally ate more fish, but Antarctic seal and whale hunting triggered an explosion in the krill population. When this type of food became more readily available, the penguins switched to krill.