Producer

MARY HOPE GARCIA

Art Director

SABINA DALEY

Designers

KAREN MATTSON

RADIK SHVARTS

Pagebuilding

BRIAN SANTALONE

Writer

DAVID MALAKOFF

Production Assistance

RUIYAN XU

Technical Director

BRIAN LEE

About the Writer

David Malakoff is a journalist covering research discoveries and the politics of science for SCIENCE MAGAZINE in Washington, D.C. His writing has appeared in a wide range of venues, including THE ECONOMIST, THE WASHINGTON POST, and ABCNews.com.

Thirteen Online is a production of Thirteen/WNET New York’s Kravis Multimedia Education Center in New York City. Anthony Chapman, Director of Interactive & Broadband. Bob Adleman, Business Manager. Carmen DiRienzo, Vice President and Managing Director, Corporate Affairs.

Television Credits

A co-production of TVNZ and Thirteen/WNET in association with NDR & NHK.

This program was produced by Thirteen/WNET, New York, which is solely responsible for its content.

Yellow-Eyed Penguin Trust
http://www.yellow-eyedpenguin.org.nz/
Describes efforts to save New Zealand’s Yellow-eyed Penguin.

Pete & Barb’s Penguin Pages
http://www.adelie.pwp.blueyonder.co.uk/
Over 100 pages of penguin information and many photographs.

Virtual Antarctica Science: Penguins
http://www.doc.ic.ac.uk/~kpt/terraquest/
va/science/penguins/penguins.html
Excellent overview of penguin research in the Antarctic.

Everything About Penguins
http://birding.about.com/msub1-penguins.htm?once=true&
About.com’s list of penguin-related resources on the Internet.

Penguins
http://www.seaworld.org/infobooks/penguins/home.html
Detailed scientific information about penguins from Sea World.

Penguins in New Zealand
http://www.penguin.net.nz/
Information on the penguin species in New Zealand, their status, and conservation. Don’t miss games, photos, and more.

Books

Gorman, James. THE TOTAL PENGUIN. New York: Prentice Hall, 1990.

Lester, Helen. TACKY THE PENGUIN. New York: Houghton Mifflin, 1988.

Love, John A. PENGUINS. New York: Whittet Books, 1994.

Todd, Frank S. THE SEAWORLD BOOK OF PENGUINS. New York: Harcourt Brace Jovanovich, 1984.

Williams, Tony D. THE PENGUINS. New York: Oxford University Press, 1995.

Ironically, some of the factors that have so endeared penguins to people have placed their survival in jeopardy. Many penguin species, for instance, are highly social birds that breed in large colonies called rookeries. Since most healthy adult penguins fear few land predators, particularly in colder climates, they have little natural fear of people. Curious birds may waddle right up to a visitor, a behavior that has turned some penguins into favorite subjects for today’s birdwatchers and wildlife photographers. In the past, however, such behaviors made penguins easy targets for human hunters and egg gatherers, who dramatically reduced some populations. At the turn of the century, for example, egg collectors gathered more than 13 million African penguin eggs from colonies on the Cape Islands off South Africa, leading to the loss of some colonies. In 1867, one company killed 405,000 penguins from the Falkland Islands alone, rendering the birds into oil. Such hunting drove the Islands’ King Penguins to the edge of extinction.

Today, the threat to penguins from hunting and egg gathering has mostly ended, though, as recently as the 1980s, one Japanese company asked the international body that governs Antarctica to be allowed to harvest Antarctic penguins for oil, meat, and skins (to be turned into high-fashion golf gloves). Luckily for the penguins, the company was turned down. Instead, the birds are now threatened primarily by destruction of their nesting habitats, competition from human fishermen for the fish and shrimp they eat, and by introduced predators — such as rats, dogs, and foxes — that eat penguin eggs and young. Currently, the species most at risk are those concentrated near human populations in temperate zones, such as the Little Blue, Yellow-eyed, African, and Humboldt penguins.

But scientists say even penguins living thousands of miles from the nearest city are at risk from a new threat: global warming caused by human alterations to the atmosphere. “Most recent changes in penguin distribution suggest that climate change is probably one of the greatest potential threats to penguins,” says Dee Boersma, a University of Washington biologist who extensively studied penguin colonies in Argentina and elsewhere. She notes that some studies have already shown that penguins are especially sensitive to climate changes. On one island, for instance, the number of breeding Rockhopper penguins dropped from 1.7 million in the 1940s to about 100,000 today, probably because surrounding seas became warmer.

Researchers fear such warming trends could be particularly hard on the penguins that live on or closest to Antarctica. Emperor penguins, for instance, nest directly on the South Polar sea ice, meaning an early thaw could endanger their chicks. And some researchers believe recent warming is responsible for the dramatic, 20-year decline in Adelie penguin populations on the Antarctic Peninsula. Researcher Wayne Trivelpiece of Montana State University suspects that warming has reduced winter sea ice, which hosts the algae that is the basis of the local food chain. Less sea ice means less food for the shrimp-like krill that is the Adelie’s major food source. The decline, he says, may be a disturbing “harbinger of what’s coming.”

But penguin experts hope that public fondness of these waddling torpedoes (what University of California biologist Gerald Kooyman calls “the cuteness factor”) will translate into strengthened protection efforts. The more the public learns about the remarkable world of penguins, researchers say, the more likely they are to understand that these elegantly clothed creatures aren’t on Earth just to provide comic relief.

It may not seem natural for a bird to fly under the sea. But since they abandoned the skies more than 50 million years ago, penguins have evolved some ingenious solutions to the challenges of a mostly marine life. Most importantly, perhaps, penguins have evolved an extraordinarily streamlined body that allows them to feed efficiently on the fish and other prey that live deep in the sea, far out of reach of their flying cousins. “Penguins have an almost perfectly hydrodynamic body profile — just what you want if you live in a water world,” says Gerald Kooyman, a University of California, San Diego biologist who has studied penguins for decades. In fact, Kooyman says, the penguin has among the most streamlined body shape ever gauged. A swimming Chinstrap penguin measuring more than seven inches wide, for instance, slices through the water with less resistance than a quarter-sized pebble.

Such streamlined design allows penguins to swim fast. While most cruise at about 5 miles per hour, some, such as Gentoo penguins, have been recorded blazing along at 15 miles per hour. Such bursts, often achieved by “porpoising,” or repeatedly leaping out of the water, probably help penguins snag quick-moving prey and escape predators like leopard seals and killer whales. Sleek bodies also help penguins travel long distances. While most species appear to cover fewer than 60 miles in a single trip, some roam vast feeding territories. King and Emperor penguins, for instance, have been known to cover almost 1,000 miles on foraging trips that last up to a month, swimming more than 40 miles per day. Adelie penguins are believed to swim up to 3,000 miles to return to their spring nesting grounds, having spent the rest of the year roaming the drifting pack ice around Antarctica.

Penguins aren’t just champion swimmers, however: Kooyman’s research has helped reveal that they are also world-class divers. In the 1970s, in an effort to understand what Emperor penguins were doing at sea, Kooyman pioneered the use of automatic dive recorders — devices attached to the penguins that recorded the depth and length of their dives. Though relatively crude, the first devices produced astonishing results: the penguins were revealed to be diving to depths of almost 900 feet in search of food. Later, more sophisticated devices recorded Emperors staying underwater for up to 11 minutes and diving to at least 1,766 feet. The devices showed that other penguins also ventured into deep waters far more often than biologists had thought possible. Researchers observed one Gentoo penguin, for instance, making more than 450 dives in 15 hours, some to lower than 300 feet.

At such depths, penguins must overcome at least one potentially deadly challenge: the enormous pressure that is squeezing their bodies. At 1,200 feet, for instance, the birds are being squashed by 40 times the pressure they feel at the surface. The big squeeze is dangerous because it crushes the air in the penguin’s lungs to just one-fortieth of its original volume, making it hard for oxygen to circulate to the brain and other vital organs. The pressure also forces nitrogen to dissolve in the blood; in humans and many other animals, the dissolved nitrogen can cause dangerous conditions called nitrogen narcosis (which can cause divers to hallucinate and make deadly mistakes in the deep) and “the bends,” a painful condition caused by the formation of nitrogen bubbles in the blood.

How do penguins avoid these problems and stay down so long? Recent research suggests that, as they free fall into the depths, the birds cut off blood flow to many parts of the body — essentially turning off all but the most essential organs, such as the heart and the brain. This not only allows the birds to hold their breaths longer, but also reduces the risk that their blood will become contaminated by nitrogen, researchers say. Whether the penguins can consciously control or limit this body shutdown, or whether it occurs automatically when they reach certain depths, is not yet known.

Penguins also have other adaptations that make them highly efficient menaces of the deep sea. Their tongues are armed with sharp, backward-facing barbs that help prevent prey from escaping. And penguin eyes appear to be adapted to multipurpose use, producing sharp vision in both the dark depths and at the sunlit surface. This is no easy accomplishment, since air and water demand very different kinds of sight. But penguins apparently make the switch smoothly by changing the shape of the lenses in their eyes to correct for differences in the way air and water transmit light. The birds seem to use fine eye muscles to bend and warp the wafer-thin lens, which is shaped much like a contact lens. Some penguins even may retain some of their ability to see color in the deep, where only blue-green light penetrates. Humboldt penguins, for instance, have eyes that are especially sensitive to blue-green light — a trait that may help them see and distinguish prey like squid.

In the spring of 1498, seamen sailing with Portuguese explorer Vasco da Gama on his historic voyage from Europe to India were astonished to discover a flock of large swimming birds leaping like porpoises from the deep waters off Southern Africa. The remarkable creatures, one sailor wrote, “had a cry resembling the braying of donkeys.” For days, da Gama’s men debated how the apparently flightless creatures survived in the frigid waters so far from land. Today, we know that da Gama’s expedition had stumbled across a flock of aptly named Jackass Penguins, also known as African Penguins. But, even now, modern researchers are still amazed by the routine feats of endurance achieved by Earth’s 18 species of penguins.

Those accomplishments are the focus of this week’s NATURE program, THE WORLD OF PENGUINS, which takes viewers on a global tour of penguin territory. From the freezing dark winters of the Antarctic ice sheet to the blistering equatorial summers of the Galapagos Islands, THE WORLD OF PENGUINS documents the ingenious adaptations that penguins have developed, allowing them to forsake the skies and prosper in some of the planet’s harshest environments. It also captures some of the complex penguin rituals, from flipper boxing and bill jousting to bowing contests and feeding chases, that have long fascinated observers.

“When most people think of penguins, they think of the very cold, icy, south polar regions,” says Tony Williams, a penguin researcher at Simon Fraser University in Canada. But in reality, he says, only two species, the Adelie and the Emperor, are confined to chilly Antarctica, where penguins deftly withstand temperatures as low as 100 degrees below zero. The majority of penguins can be found throughout the cool southern oceans, breeding on islands and the coastlines of Africa, South America, and Australia. The northernmost species, the Galapagos Penguin, lives on those tropical islands just a few miles north of the equator.

Although they are spread across the southern half of the globe, far-flung penguins have much in common. All species share torpedo-shaped bodies that sport the same basic color scheme of dark backs and white bellies. This outfit makes for perfect camouflage in the sea both from above and below. Instead of broad, long wings and tails suitable for flight, penguins have stiff paddle-like flippers, stubby tails, and broad feet that allow them to “fly” underwater. Similarly, penguins have lost the light, hollow bones that help flying birds stay aloft; instead, they have heavy, solid bones that are an advantage for a bird that often must dive deep to find the fish, squid, and shrimp they usually eat. Sadly, many penguins are also beginning to have something else in common: their survival is endangered by a wide range of threats, from habitat destruction to changes in the global climate.

While similar, each species also displays its own variation on the basic penguin theme. The pattern and color of head feathers, for instance, varies greatly from bird to bird. Antarctica’s Emperor and King penguins complement their feathery tuxedos with dramatic bright orange patches on their heads and bills. Six other species — the Rockhopper, Erect-crested, Fiordland, Snares, Macaroni, and Royal penguins — sport elaborate yellow crests and plumes that give them a festive look. One species, Australia and New Zealand’s Little Penguin, has even traded the traditional penguin black-tie look for a lustrous blue-gray coat — hence its nickname, “Little Blue.”

The Little Blue’s name is fitting in another respect: it is the world’s smallest penguin, measuring just 18 inches tall and weighing a little over two pounds. In contrast, Emperor Penguins — the world’s largest species — can reach almost four feet and 90 pounds, the size of a young child.

No matter their size, people often think of penguins as the awkward, waddling buffoons of the bird world. That is largely because most photographs and films of penguins are taken on land, where the birds are easy to find as they congregate to breed and wait for feathers to drop out and regrow. However, most penguins actually spend only a small part of their lives on land. The majority of the time — for some species, up to 80 percent of it — penguins are at home in the ocean, feeding or simply resting at the surface. And once at sea, penguins are far from clumsy. Indeed, they are the avian equivalent of attack submarines: sleek, deadly predators designed for speed, deep diving, and the survival of harsh conditions.

Meet those well-loved, well-dressed flightless birds in THE WORLD OF PENGUINS.

We all have an image of penguins gliding on ice at the South Pole — images that come from childhood. But contrary to popular belief penguins live beyond Antarctica, and can be found in New Zealand, southern Africa, and South America. While some species have adapted to life in regions that reach 100 degrees below zero others are comfortable in temperatures 100 degrees above. The classic tuxedoed penguins are found in Antarctica, along with the largest, the Emperor penguins, while Jackass penguins flourish in Namibia and South Africa and Humboldts live on a desert landscape near the coasts of Peru and Chile.

Though they are considered birds — they lay eggs and have feathers — penguins spend most of their lives at sea as fast and powerful predators — a stark contrast to the clumsy, waddling penguin on land. The penguin’s powerful flippers, gives them the ability to dive and hunt at ocean depths where no other bird can go.

No matter how awkward it is, every penguin must return to land. Each year penguins forsake the sea and struggle ashore to mate and lay eggs. Rockhopper penguins climb 90 foot cliffs to their nest; Adelies travel 3,000 perilous miles to breeding colonies.

Join NATURE and travel to “The World of Penguins” to discover the great variety of these aquatic birds.

To order a copy of The World of Penguins, please visit the NATURE Shop.

Online content for The World of Penguins was originally posted March 1997.