Penguins feed on marine zooplankton, mainly Antarctic krill, and sometimes some wrasses, squid and small fish.

Penguins have a good appetite, with each penguin eating an average of 0.75 kilograms of food per day, mainly Antarctic krill. Penguins therefore play an important role as predators in the Southern Ocean food chain.

Penguins in the Antarctic predation of krill about 33.17 million tons, accounting for 90% of the total consumption of Antarctic birds, equivalent to half of the whale predation krill. Penguins, known as the "boats of the sea," are one of the oldest birds of prey, and it is likely that they made their home in Antarctica before the Earth put on its ice armor.

The penguin's habitat varies according to species and distribution area: Emperor penguins like to roost on ice shelves and sea ice; Adelie penguins and Kintu penguins can live on both sea ice and rocky outcroppings in ice-free zones; penguins in the sub-Antarctic mostly like to roost on rocky outcroppings in ice-free zones and commonly use rocks to build their nests. Penguins like to roost in groups, a group of hundreds, thousands, tens of thousands, the most even up to 10 ~ 20 million.

On the ice shelves of the Antarctic continent, or on the icebergs and ice floes of the Southern Ocean, one can see the penguins gathering in large groups. Sometimes, they line up in a neat procession, facing a direction, as if a well-trained honor guard, waiting for and welcoming guests from afar; sometimes they are lined up into a distance, equal intervals between the squads, such as group exercise performance of the athletes, the formation is very neat and spectacular.