The penguin's bones are solid and heavy, which help them to remain submerged and reduce the energy needed for diving. Penguins are able to withstand the extreme cold because insulation provided by their short, densely-packed feathers forms a waterproof coat. A thick layer of fat or blubber also serves as an energy store. These adaptations, among others, enable them to minimize heat loss in icy cold waters so they can cope with the harsh conditions of the Antarctic. Return Behavior Penguins communicate by complex ritual behaviors such as head and flipper waving, calling, bowing, gesturing and preening.
Territorial disputes lead to aggressive postures such as stares, pointing and even charging.
This can result in a mass trumpeting by other males, which is believed to help synchronize the breeding cycle. Adult pairs take turns incubating their eggs and feeding the chicks once they have hatched. Antarctic penguins feed mostly on fish, squid and krill, a shrimp-like crustacean which is the key species in the Antarctic ecosystem. Return Locomotion Penguins are very efficient swimmers. This enables them to breathe, and decreases their chances of being taken by a predator.