Penguin

About the penguin

Penguins are flightless, semi-aquatic seabirds that live almost entirely in the Southern Hemisphere, with the Galápagos penguin as the sole exception, ranging at and just north of the equator. They belong to the family Spheniscidae within the order Sphenisciformes, a name built from the Greek word for "wedge," describing the shape of a penguin's swimming flippers. The International Ornithologists' Union currently recognizes eighteen species across six genera, though other sources put the total number of species between seventeen and nineteen depending on classification.

Penguins are built for the water rather than the air: their wings have become flippers, and their plumage is countershaded, dark on top and white below. Size varies enormously across the family and tracks climate — larger penguins generally live in colder regions and smaller ones in temperate or tropical climates. The largest living species, the emperor penguin, stands about 3 feet 7 inches tall and weighs around 77 pounds on average, while the smallest, the little blue penguin (also called the fairy penguin), stands only 12 to 13 inches tall and weighs 2.6 to 2.9 pounds. Some prehistoric penguins dwarfed even the emperor penguin, growing as tall or as heavy as an adult human.

The word "penguin" itself was first applied not to these birds but to the great auk, an unrelated Northern Hemisphere seabird, because early European explorers thought the two looked alike. The name was later transferred to the unrelated Southern Hemisphere birds now called penguins, which were formally classified into their own family and order in 1831.

The earliest penguin ancestors lived around the time of the Cretaceous-Paleogene extinction event, roughly 70 to 68 million years ago, in the area of what is now southern New Zealand and Antarctica's Byrd Land, which were much closer together at the time. The oldest known penguin fossils, belonging to several now-extinct genera, come from the Waipara Greensand of New Zealand and date to between about 62.5 and 58 million years ago; unlike modern penguins, these early birds were not yet as well adapted to life underwater, though they were already flightless with short wings suited to diving. By about 42 million years ago, penguin relatives had reached as far as northern Peru, and by roughly 39 to 38 million years ago they had spread into South America and begun expanding into Atlantic waters. A group of penguins swimming together in the water is sometimes called a raft.

The living penguin genera differ from one another in visible ways. Aptenodytes, which includes the emperor penguin, has bright yellow-orange patches on the neck, breast, and bill and is centered on Antarctic coasts. Pygoscelis has a simpler black-and-white head pattern and a range that extends somewhat farther north from Antarctica. Spheniscus and Eudyptula, found mostly around South America and in temperate waters, lack the yellow and orange pigments seen in other genera, have a banded head pattern in Spheniscus, and are unique among living penguins in nesting inside burrows. The Megadyptes-Eudyptes group carries hairy yellow ornamental head feathers and partly red bills, and reaches its highest diversity in the New Zealand region.

Behavior and diet

Penguins split their lives roughly in half between land and sea. In the water, they hunt using a spiny tongue and powerful jaws to grip slippery prey, feeding mainly on krill, fish, squid, and other sea life, which they catch with their bills and swallow whole. On land, penguin behavior varies by genus. In the genus Aptenodytes, which includes the largest species, adults incubate their eggs by balancing them on their feet rather than building a nest, and the chicks that result hatch almost naked.

Range and habitat

Penguins are found almost exclusively in the Southern Hemisphere, occupying coastlines and offshore waters from the ice-bound edges of Antarctica to the temperate and tropical shores of South America, southern Africa, Australia, and New Zealand. The Galápagos penguin is the single exception to this pattern, living at and just north of the equator. As a general rule, the largest species live in the coldest parts of this range and the smallest species live in its warmer reaches, a pattern reflected across the family from the massive, cold-adapted emperor penguin to the smaller, temperate-zone little blue penguin.

Conservation status

Penguins have no single conservation status, because the IUCN Red List assesses each species separately. Their ratings run from Least Concern to Critically Endangered, and the majority of living species have declining populations.

The king penguin and Adélie penguin are Least Concern with increasing numbers. At the other end, the African penguin is Critically Endangered, with about 19,800 mature birds in a 2024 assessment, and the emperor, Galápagos, yellow-eyed, erect-crested and northern rockhopper penguins are Endangered. The Galápagos penguin is down to about 1,200 mature birds. The Humboldt penguin is among several species listed as Vulnerable.

Penguins have faced decline before. Giant species that stood nearly 6 feet tall and weighed 180 pounds or more died out by around 25 million years ago, at about the time large fish-eating toothed whales spread and competed with them for food.