For penguins, temperature is everything, their waterproof feathers keeping them both cool and warm. Keeping cool is one of the penguin’s main pre-occupations. On land, their elongated bodies and flightless flippers limit their movement to a slow gait, forcing them to lead a sedentary existence. This makes them easy to observe during Antarctica tours and travel to Patagonia. Breeding in the shade or burrows and staying underwater also keep the temperature to their liking. Some species have patches of featherless skin that allow heat to escape. Species that inhabit the coldest climates are aided in keeping warm by long, dense feathers as well as by the habit of huddling together.
Penguins are social creatures, living in colonies that vary in size by species, living in close quarters, called rookeries, during the breeding season. Most penguins breed for life, though how monogamous a penguin is depends on the weather among other factors. Because the Adelie penguin lives so far south, its necessarily short breeding season makes this species less than loyal some years. The Emperor Penguin is only serially monogamous, usually selecting a new mate each year so as not to miss the breeding opportunity by waiting around for a mate that may not appear.
Most penguins breed during the summer months. Penguins lay thick-shelled eggs, larger species laying one and smaller species usually two. Incubation takes one to two months, depending on the species. In all penguin species, males share parenting responsibilities with the female, though some species help more than others. All participate in keeping eggs warm and some produce milk that is regurgitated for the young. Depending on their nesting habits, some species have brood pouches to protect and warm their eggs as a substitute for a nest.
After chicks are able to control their own body temperature, the family joins the crèche where penguins crowd together for protection and warmth. This arrangement allows the parents to leave long enough to fish and return with food for their young. Besides the penguin’s adorable gait, it is this habit of forming nurseries to cooperatively raise their young that endears these birds to humans and makes them popular with visitors on South America tours.
Penguins are born covered in down. When they acquire their first water-proof feathers, they lose their down and are ready to swim, then called fledglings. As juveniles, they will eventually molt again, gaining their adult feathers.
Surrounded by miles of water without a drop to drink describes the habitat of penguins. Fortunately they are equipped with a facial gland that removes excess salt through their bill as they feed. Krill is the staple of the penguin diet, supplemented by other crustaceans and small fish. Larger species such as the Macaroni Penguin, the Magellanic Penguinand the King Penguin add in squid, and the Emperor even larger species.