Penguins are a famous family of flightless birds. They are highly adapted to living a life in the sea and are found almost exclusively in the cooler waters of the Southern Hemisphere. Several physiological adaptations have allowed them to thrive in cold environments, such as Antarctica and sub-Antarctic islands, and prosper in the cold water surrounding these locations. There is a total of 17 penguin species clumped into 6 genera. They are generally long-lived birds and often form long-term mating pairs.

Body structure

A penguin’s body plan is highly designed for a marine life. They have streamlined bodies that help to reduce drag in the water and highly modified wings that form stiff, flat flippers that are used to propel themselves through water. As opposed to most birds that have hollow, light bones to reduce weight for flying, a penguin’s bones are heavy and solid to reduce the amount of energy required to dive.

Penguins have a dark plumage on the backside and light plumage on their front as a form of camouflage from predators in the water. Looking down on a penguin in water, its dark back blends into the dark deep waters below and looking up at a penguin from deeper water, its light underside blends into the lighter waters towards the surface.

Short, stiff feathers form a dense coat and provides penguins with a good layer of insulation while in water or a cold climate. Their legs are short and sit far back on their body. Together with the penguin’s tail, its legs form a solid rudder. Although they often look awkward walking on land, they can travel over 3 km by foot but often revert to tobogganing across ice and snow in colder locations.

Penguins range in size from 1-30 kg and 30-120 cm tall. The smallest species is the little penguin (Eudyptula minor) and the largest species is the emperor penguin (Aptenodytes forsteri) which is found only in Antarctica.

Distribution of penguins

Penguins are found in cool waters of the Southern Hemisphere and only cross the equator into the Northern Hemisphere at the Galapagos Islands. The Adelie and Emperor penguins are the only species found on mainland Antarctica, the remaining species are distributed through the Southern Ocean up to New Zealand, Australia, Africa and South America.

They are most abundant in Antarctica and sub-Antarctic regions and make up as much as 80% of the sub-Antarctic bird life. The greatest diversity is found in the sub-Antarctic islands south of New Zealand.

Although they spend most of their time at sea, they do require land for breeding, rearing chicks and molting. They utilize a number of different nesting habitats on land such as beaches, snow, grasslands and forests and the Galapagos penguins nest in desert-like lava flows.

Diversity of penguins

There is a total of 17 different species of penguins from 6 different genera. The most significant differences between each species are differences in body size and the appearance of their heads.

Fossil records indicate that there have been at least 40 different penguin species in the past, many of which lived along the Antarctic coast. Of the current living species of birds, penguins are most closely related to petrels and albatrosses.

Species list: Adele, Africa, Chinstrap, Emperor, Erect-crested, Fiordland, Galapagos, Gentoo, Humboldt, King, Little, Macaroni, Magellanic, Rockhopper, Royal, Snares, Yellow-eyed

Life history

Penguins are relatively long live birds with some birds living for over 30 years. They are typically monogamous birds, forming long-term mating pairs that can last for several breeding seasons. Most species breed each year, laying their eggs in spring a rearing their chicks over the summer.

Emperor penguins are unusual because they rear their chicks through the Antarctic winter and are the only species to breed in Antarctica. The majority of species nest in colonies and some colonies exceed over 200,000 breeding pairs.

All birds must molt their feathers each year and grow a new plumage. This is a process that can take several weeks. While penguins are molting they are unable to feed because they lack their insulating coat of feathers for the water. Most species molt once their chicks have fledged at the end of summer. The crested penguins fast for around 40 days while they molt but they are put to shame by male emperor penguins who must endure 120 days of fasting while they rear their chicks through the Antarctic winter.

Penguins spend up to 80% of their life in water. All species feed at sea including during the breeding season. For many species, the only time they return to land is to breed and molt. Most species feed on fish, squid and crustaceans.

Many penguin species are impressive divers. Emperor penguins are able to dive deeper than 400 m and for longer than 10 minutes at a time.

Last edited: 16 December 2015