The term "self-maintenance" should not generate any confusion as to what it means; it simply consists of those behaviours animals employ to ensure that their bodies are properly maintained (not including feeding).

    For birds, this behaviour entails a great deal of feather maintenance. Birds that fly must ensure that their feathers are properly preened so that they a) attain low drag during flight and b) are protected from the weather. The case is no different in penguins. Although penguins do not fly, feathers must be sufficiently groomed to prevent water infiltration. This is a crucial facet of penguin biology since maintaining a high degree of air insulation is vital to survival for some penguins.

    In my own observations of Humboldt penguins, the early morning hours before feeding time were spent preening, both on land and in the water. Penguins gather oil from a preening gland located on the rump, from where the tail originates. This oil is applied to feathers and to the edges of the flippers; oil on the flippers is subsequently transferred to the unreachable regions of the head. Additionally, a penguin will enter the water and preen various regions of the body. Following this preening, the penguin will rub the flipper over the region while rotating its body as it coasts along in the water. It appears as if the penguin is side-stroking.

    Often one penguin may preen another penguin. This occurs both intra-sexually and inter-sexually. These acts will be discussed in later sections.

    Another aspect of self-maintenance entails huddling. One French explorer described this event as resembling a giant turtle on the beach. Penguins, especially young, gather together to minimize heat loss. There are a number of assumptions that surround the nature of these huddles. If you would like to read about what I think of penguin huddling, please go over to the section on Deconstructing Penguin Myths.

    Even penguins get hot. Like all birds penguins release heat through several activities: panting, lifting wings, stream-lining feathers or entering the water. Stream-lining feathers reduces the volume of air between the skin and the edge of the feathers. This layer of air serves as an insulator, and when it is minimized, heat is easily expelled from the body.

    By and large, penguins eat small fish and crustaceans; however, larger penguins like the emperor or king penguin have been known to take larger fish and even squid.

    Several comprehensive studies of penguins have been made in recent years of foraging behaviour. In contrast to older studies, these new methods include time-depth recorders and micro-satellite techniques that enable researchers to locate the penguins and the food they capture. When attacking their prey, generally penguins approach fish from the side, and when caught, they rotate the fish in their bills so that they are swallowed head first.

    What I have noticed in my study is that Humboldt penguins tend to circle around a body of fish before diving deeper to catch them. Oliver (1955) noted that Little blue penguins drove fish into dense packs before driving through the mass of fish.

    Nevertheless, penguins don't seem to be as indiscriminate foragers as other aquatic animals may be, as they don't swim through the waters with their bills open. Instead, they seem to capture a few fish or crustaceans before swallowing.

    See Species Information for descriptions lists of food taken by specific penguins.