Penguin Facts

Aptenodytes, Eudyptes, Eudyptula Pygoscelis, Spheniscus, and Megadyptes

Gentoo penguin walking

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Penguins (Aptenodytes, Eudyptes, Eudyptula Pygoscelis, Spheniscus, and Megadyptes species) are perennially popular birds: chubby, tuxedo-clad creatures that waddle charmingly across the rocks and ice floes and belly flop into the sea.

Fast Facts: Penguins

  • Scientific Name: Aptenodytes, Eudyptes, Eudyptula Pygoscelis, Spheniscus, Megadyptes
  • Common Name: Penguin
  • Basic Animal Group: Bird  
  • Size: range from 17–48 inches
  • Weight: 3.3–30 pounds
  • Lifespan: 6–30 years
  • Diet: Carnivore
  • Habitat: Oceans in the southern hemisphere, and the Galapagos Islands
  • Conservation Status: Five species are listed as Endangered, five are Vulnerable, three are Near Threatened

Description

Molting penguin
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Penguins are birds, and although they may not look like our other feathered friends, but they are, indeed, feathered. Because they spend so much of their lives in the water, they keep their feathers slicked down and waterproofed. Penguins have a special oil gland, called a preen gland, that produces a steady supply of waterproofing oil. A penguin uses its beak to apply the substance to its feathers regularly. Their oiled feathers help keep them warm in the frigid waters, and also reduce drag when they're swimming.

Like other birds, penguins molt old feathers and regrow replacements. But instead of losing some feathers at different times throughout the year, penguins do their molting all at once. This is known as a catastrophic molt. Once each year, the penguin bulks up on fish to prepare for its annual changing of the feathers. Then, over a period of a few weeks, it molts all of its feathers and grows new ones. Because its feathers are so vital to its ability to survive in cold waters, it makes sense for a penguin to simply stay on land for a few weeks and replace its overcoat once a year.

Though penguins technically have wings like other birds do, those wings are not like other birds' wings. Penguin wings are not built for flight. In fact, penguins can't fly at all. Their wings are flattened and tapered and look and function more like dolphin fins than bird wings.

Evolutionary biologists believe penguins could fly in the past, but over millions of years, their flight skills diminished. Penguins became efficient divers and swimmers, built like torpedoes, with wings designed for propelling their bodies through the water instead of air. A study published in 2013 determined this evolution was rooted in energy efficiency. Birds that both swim and fly, like the thick-billed murre, expend an enormous amount of energy in the air. Because their wings are modified for diving, they're less aerodynamic, and it takes more energy for them to get airborne. Penguins made an evolutionary bet that being good swimmers would serve them better than trying to do both. So they went all in on functioning ​flippers and gave up their ability to take flight.

Swimming penguin
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Once prehistoric penguins committed to living in the water instead of the air, they proved themselves to be world champion swimmers. Most move between 4–7 mph underwater, but the zippy gentoo penguin (Pygoscelis papua) can propel itself through the water at 22 mph. Penguins can dive hundreds of feet deep, and stay submerged for as long as 20 minutes. And they can launch themselves out of the water like porpoises, to avoid predators below the surface or to return to the surface of the ice.

Birds have hollow bones so they're lighter in the air, but a penguin's bones are thicker and heavier. Just as a SCUBA divers use weights to control their buoyancy, a penguin relies on its beefier bones to counteract its tendency to float. When they need to make a quick escape from the water, penguins release air bubbles trapped between their feathers to instantly decrease drag and increase speed. Their bodies are streamlined for speed in the water.

Of all the recognized species of penguins, the largest is the Emperor penguin (Aptenodytes forsteri), who can grown to four feet in height and 50–100 pounds in weight. The smallest is the little penguin (Eudyptula minor) who grows to an average 17 inches in length and weighs about 3.3 pounds.

Habitat

Don't travel to Alaska if you're looking for penguins. There are 19 described species of penguins on the planet, and all but one of them lives below the equator. Despite the common misconception that all penguins live among the icebergs of the Antarctic, that's not true, either. Penguins live on every continent in the Southern Hemisphere, including Africa, South America, and Australia. Most inhabit islands where they aren't threatened by large predators. The only species that lives north of the equator is the Galapagos penguin (Spheniscus mendiculus), which lives, as you may have guessed, in the Galapagos Islands.

Diet

Penguin eating fish.
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Most penguins feed on whatever they manage to catch while swimming and diving. They'll eat any marine creature they can catch and swallow: fish, crabs, shrimp, squid, octopus, or krill. Like other birds, penguins don't have teeth, and can't chew their food. Instead, they have fleshy, backward-pointing spines inside their mouths, and they use these to guide their prey down their throats. An average-sized penguin eats two pounds of seafood per day during the summer months.

Krill, a small marine crustacean, is a particularly important part of the diet for young penguin chicks. One long term study of the diet of gentoo penguins found that breeding success was directly related to how much krill they ate. Penguin parents forage for krill and fish at sea and then travel back to their chicks on land to regurgitate the food into their mouths. Macaroni penguins (Eudyptes chrysolphus) are specialist feeders; they depend on krill alone for their nutrition.

Reproduction and Offspring

Emperor penguin chick on father's feet.
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Nearly all penguin species practice monogamy, meaning a male and female mate exclusively with each other for the breeding season. Some even remain partners for life. Penguins reach sexual maturity between three and eight years of age. The male penguin usually finds himself a nice nesting site before attempting to court a female.

Penguins parent together, with both mother and father caring for and feeding their young. Most species produce two eggs at a time, but emperor penguins (Aptenodytes forsteri, the largest of all the penguins) raise just one chick at a time. The emperor penguin male takes sole responsibility for keeping their egg warm, by holding it on his feet and under his folds of fat, while the female journeys to the sea for food.

Threats

African penguins snapping at the camera
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Scientists warn that penguins worldwide are threatened by climate change, and some species may soon disappear. Penguins rely on food sources that are sensitive to changes in ocean temperatures, and dependent on polar ice. As the planet warms, the sea ice melting season lasts longer, impacting krill populations and penguin habitat.

Five species of penguins are already classified as endangered (Yellow-eyed, Galapagos, Erect Crested, African, and Northern Rockhopper), and most of the remaining species are vulnerable or near threatened, according to the International Union for Conservation of Nature's Red List. The African penguin (Spheniscus demersus) is the most endangered species on the list. 

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