Penguins feed on plankton, fish, and cephalopods, depending on the species and the season. To remove excess salt from their food, the kidneys are not enough; like other seabirds, they have "salt glands" above the eye sockets and leading out through an excretory channel.
After their meal, they shake their head to chase the "beak drop". Penguins observe long periods of fasting when on land to breed and during molting.

All nest on land, or on the ice: some in burrows they dig or under boulders, the others in the open, on a rudimentary nest. Only the emperor and the royal penguin do not have a nest. After a period of fattening at sea, the males find their nests on land, sometimes a hundred kilometers away, where the females join them. These penguins are monogamous and we often see the same couples forming. Penguins lay one or two eggs, but only one chick is usually kept. The parents incubate alternately and take turns to feed their chick according to a "calendar" specific to the species. They regurgitate the food that the chick comes to take in their crop (a pouch under the throat where they store food)

Penguins form huge colonies with sometimes several thousand pairs, often of different species, in one location. The chicks are often gathered in crèches, which limits predation and improves the thermoregulation of the young, i.e. the ability of the body to remain at a desired temperature. Calls, plumage, but also postures or head movements are used to communicate (parade, defense of territory, etc.). Each chick has its own call, recognized by the parents despite the large size of the colonies.

The only predators of penguins are killer whales, seals, and leopard seals, or, on land, skuas, jaegers, and giant petrels, which attack the weakest. Man has exploited penguins for their eggs, their feathers and especially their oil (the pressed bodies were used as fuel under seal or whale fat pots). They are currently protected.
Nevertheless, studies have shown that large temperature variations in the past have greatly disturbed penguin populations, which may suggest that the current climate disruption may have an effect on their ability to both feed and find habitat, due to poor sea ice conditions.

Papuan penguin (Pygoscelis papua)
Lays two eggs in September/October on a nest of rocks sometimes covered with plants or feathers (Incubation: 35 days). Feeds mostly on fish, sometimes on crustaceans and squid. Measures between 75 and 80 cm, but it is not the smallest of the penguins. They nest in very noisy and smelly rookeries.

The chinstrap penguin (Pygoscelis antarctica)
Lays two eggs on a gravel nest. It is aggressive and sometimes steals the nests of Adélie penguins, which live in the same habitat. Likes to settle on icebergs. Feeds on krill and some fish.

The jumping gorfou (Eudyptes chrysocome)
Leaps over scree instead of going around it on its belly as other species do. Lays two eggs, of which only one will hatch, in a nest strongly protected by the parents. Feeds on krill and fish. It can be distinguished from the golden gorfou by the color of its eyes and the shape of its yellow egrets.