Their only natural enemies of the penguin include leopard seals, killer whales, and, in the case of young chicks and eggs, skuas. They live in their colonies to keep eachother safe. They watch over eachothers chicks. When swimming they usually aren't alone. Although penguins aren't flyers they are great swimmers.
Penguins usually walk or hop and toboggan along on their breasts, pushing with wings and feet.
They swim with great speed and agility. Some species progress by porpoising, which is swimming underwater some distance, emerging in a graceful arc to take a fresh breath, and submerging again. Penguins do not have specific feather tracts, as do most birds, but are covered almost uniformly with small, scalelike feathers. Whereas most birds shed their feathers and grow new ones during a relatively long period of the year, penguins molt all of their feathers and, in some species, even shed the shields from the beak within a short space of time. During the molting period, which may last several weeks, the penguin does not enter the water to feed.