Escape VelocityAwkward on land, emperor penguins soar through the sea. Now scientists have discovered the secret of their speed.

An airborne penguin shows why it has a need for speed: To get out of the water, it may have to clear several feet of ice. A fast exit also helps it elude leopard seals, which often lurk at the ice edge.

An emperor’s dense feathers—about a hundred per square inch that overlap like roof tiles—seal out water and trap air in a downy underlayer. When released, the air coats the bird in lubricating bubbles.

After hunting at sea to get food for their chicks, adult penguins swim at the surface, which loads their plumage with air. Then they’ll dive deep, gather speed, and race toward their exit hole.

At a colony on the frozen Ross Sea, emperor parents and chicks bask in the brief summer sun. The distance to open water varies with the season; in midwinter birds may have to cross many miles of ice to feed.

Life is safer at the colony, where predators are few and company is close.

The danger of ambush by leopard seals is greatest when entering the water, so penguins sometimes linger at the edge of an ice hole for hours, waiting for one bold bird to plunge in.

Emperors can bolt away for any number of reasons, as photographer Paul Nicklen discovered when he spooked this group. “A tenth of a second after I took this picture, all I could see were bubbles.”

“These penguins have probably never seen a human in the water,” says photographer Paul Nicklen, “but it took them only seconds to realize that I posed no danger. They relaxed and allowed me to share their hole in the sea ice.”

Emperor penguins are Olympian swimmers, capable of diving to 1,750 feet and remaining underwater 20 minutes on a single

breath. “I was mesmerized by their beautiful bubble trails,” says Nicklen, who braved 28°F water to capture these images.

Emperor penguins mill in the depths as they prepare for their swift ascent to the sea ice. “Once they start to launch,” says Nicklen, “within 30 seconds they’re all standing on the ice.”

Without the safety of numbers, a lone penguin corkscrews to get a 360-degree view of its surroundings. When it leaps from the water, it will land with a thump and a squeak and leave its most graceful moves behind.

Deadly BeautyA photographer falls under the spell of Antarctica's leopard seals.

I expected this 12-foot-long (4 meters) female to flee with her catch, a live penguin chick, but instead she dropped it on my camera. Then she opened her mouth and engulfed the camera-and most of my head. After 45 minutes of more threats, she finally relaxed and ate. The next day, as if wanting an audience, she came looking for me.

On alert, an adult leopard seal pauses between acrobatic hunting forays. Leopard seals are the only known seals to regularly hunt warm-blooded prey. But during the three weeks I swam with them, they often revealed a playful side.

A diver face-to-face with a leopard seal

A powerful young seal toys with a gentoo penguin. Leopard seals are opportunistic hunters, taking krill, fish, squid, and other seals as well as penguins.

This seal appeared out of nowhere, propelled by curiosity and powerful flippers. Solitary as adults, leopard seals roam so widely in the pack ice that little is known of their biology or even their numbers. Estimates range from 200,000 to 400,000.

In a lethal game of cat and mouse, the large female I encountered earlier caught and released this penguin chick, foreground, for more than an hour, repeatedly presenting it to me. When I ignored her, she blew a stream of bubbles from her nose in a threat display and tried again.

After a big female seal realized I was unable to catch a swimming penguin, she tried other ways of presenting her offerings.

More frightening than the canines of the large female was the deep jackhammer sound she let loose that rattled through my chest. She was warning off another leopard seal that had snuck behind me. It worked-the visitor moved on.

In a death shake, the large female shreds a penguin chick by whipping it from side to side. It took 1/2000 of a second to freeze the action; at the time all I saw was a splash and storm petrels and gulls gathering for scraps. This efficient killing machine prizes above all else penguin stomachs stuffed with krill.

The large female dives to eat her prey. Because leopard seals eat whatever is available, scientists track their diets to help gauge changes in the food web caused by global warming. The Antarctic Peninsula is one of the most rapidly warming places on Earth. By chemically analyzing a seal's whiskers, scientists can glean roughly three years of feeding patterns.

Life renews itself: A penguin carcass feeds a host of sea stars. Ribbon worms and smaller creatures will join the feast next. Days later only bone will remain.

Sated from a morning feast, a leopard seal rests on a piece of freshly calved glacier ice in Lemaire Channel. I had arrived in Antarctica nervous, well aware of the animal's fierce reputation. I left humbled, knowing I had experienced a powerful and rare meeting in the sea.

A leopard seal plunges through Antarctic waters. Swift and stealthy, adult leopard seals tend to be solitary creatures, hunting alone at the fringes of pack ice. Finding a mate can be challenging, given their isolation and the fact that females are in estrus only a few days each year. Both males and females sing, a trait uncommon among mammals. But females sing to announce their readiness to mate. Male leopard seals will spend as many as 13 hours a day serenading potential mates with complex melodies that can carry 25 miles (40 kilometers) underwater. Australian researcher Tracey Rogers describes the songs, produced as the males rock back and forth, as "soulful and stylized."

Over the course of a five-day photographic study, she brought him approximately 30 penguins, beginning with live penguins, then weaker penguins to make it easier for him, dead penguins — and even demonstrated how to eat one.

Young gentoo penguins take a cautionary first dive into an Antarctic sea. They have good reason to be wary of the predators that lurk beneath-penguins compose a significant part of the leopard seal diet, and the younger birds are particularly vulnerable. In Antarctica's summer, when 14- to 16-week-old penguins make their initial leaps from land to water, leopard seals stake out penguin colonies; the newly fledged birds make easy targets.

A young leopard seal plays with its food, a gentoo penguin. The 1,000-pound (450 kilograms) creatures "are not empathetic," says photographer Paul Nicklen, who spent three weeks swimming with the seals. "Killing seems as much about fun and games as it does about eating." Nicklen observed leopard seals prolonging their prey's death for over an hour by shaking the animal, dropping it, and snapping it back up again. Sometimes the penguin would die not from its wounds, but rather from the shock or stress of the chase.

A sociable female leopard seal poses on an ice shelf. While toying with her soon-to-be dinner, the leopard seal would "slide along the iceberg with the penguin, contorting her body in the most elegant postures," says Nicklen. She repeatedly offered her prey to the photographer, perhaps to see what this newcomer would do with it

A lone leopard seal rests on glacier ice. Much of the species' true nature still eludes marine mammal experts, with questions surrounding breeding habits and population size. As the only known seals to regularly eat warm-blooded animals, they are often cast as the pernicious predator, quick to snap at anything that comes their way. But Nicklen encountered the seldom seen curiosity of this wild and unpredictable animal. "I experienced a true and rare meeting in the sea with an incredible predator," he says. "I felt we were like two animals, connecting, relating, and respecting each other."

Paul Nicklen emerges numb from the cold after an hour under the ice. Admiralty Inlet, Nunavut, Canada

Polar ObsessionNational Geographic photographer and biographer Paul Nicklen has been making bold expeditions to the Arctic and Antarctic for many years, documenting the lives and habitats of leopard seals, whales, walruses, polar bears, bearded seals and narwhals and how they are threatened by climate change.

Drifts of Barents Sea ice can still bear the weight of a bear, but this young male is leaping into a changing world.

An Atlantic walrus plods toward shore after gorging on clams in the shallows. Such a big bull may stir up, shell, and suck down thousands of clams a day in summer, relying on his muzzle full of sensitive whiskers, called vibrissae, to help locate prey.

A female bear and cub test the air on an iceberg after a swim. Not tied to specific territories, bears roam widely in search of food, often leapfrogging from berg to berg. Bears fitted with satellite collars have been tracked on long swims—up to 150 miles (240 kilometers) across open ocean.

In the Arctic spring, meltwater channels drain toward and down a seal hole, returning to the sea.

Looking towards an uncertain future, a huge male bear triggers a camera trap, taking his own picture. Leifdefjorden, Spitsbergen, Norway.

Polar Bears, Svalbard Young male polar bears spar under the low light of winter in Svalbard, a cluster of islands halfway between Norway and the North Pole. Polar bears thrive here—roughly half the estimated 3,000 bears in the Berents Sea population raise their young on the archipelago's isolated islands.

A kittiwake soars in front of a large iceberg. Svalbard, Norway.

A gentoo penguin chick peeks, checking for leopard seals before tempting fate.

Nicklen's friend, the female leopard seal, greets a fellow adventurer near Anvers Island.

Narwhals dive deep under the ice to feed on Arctic cod, then return to the surface to breathe and raise their tusks high in the air. Lancaster Sound, Nunavut, Canada.

A ringed seal scans for polar bears before snatching a breath. Stealthy bears grab seals at these icy holes.

Its image mirrored in icy water, a polar bear travels submerged—a tactic often used to surprise prey. Scientists fear global warming could drive bears to extinction sometime this century.

Walrus and Calf, Foxe Basin A walrus and her calf rest on a piece of multiyear ice in Foxe Basin, Canada. The floating ice keeps them perched over favorite feeding grounds—clam beds—and allows the mother to whisk her calf to safety in the water should a polar bear appear.

Leopard Seal, Anvers Island Propelled by curiosity and powerful flippers, a leopard seal patrols a penguin rookery near Anvers Island, Antarctica. Solitary as adults, leopard seals roam so widely in the pack ice that little is known of their biology or even their numbers. Estimates range from 200,000 to 400,000.

Chinstrap Penguins, Anvers Island Young chinstrap penguins rest on an iceberg near Anvers Island, Antarctica. These penguins, which rely less on sea ice than other species do for their survival, have thrived as climate change has warmed the ocean around Antarctica.

Narwhals, Admiralty Inlet Male narwhals rest in Canada's Admiralty Inlet. In spring, as the ice pack recedes, narwhals push into cracks and holes as they migrate. Their compact size and lack of dorsal fins aid travel beneath the ice. The annual migration also brings them within range of human hunters.

Ivory Gull, Hornsund An ivory gull lands on ice in Hornsund, a fjord on Spitsbergen, the largest of Svalbard's islands. Glacial ice covers more than half the terrain of this archipelago, which lies 400 miles (640 kilometers) north of the Norwegian mainland.

Elephant Seal Pup, South Georgia An elephant seal pup plays in a freshwater stream on South Georgia, a remote British outpost in the far South Atlantic. Hundreds of thousands of southern elephant seals come to the island each summer to breed and to rear their young.

Walrus, Svalbard Both male and female walruses have tusks—actually canine teeth—used to haul their bodies out of the ice and break breathing holes into ice from below. Bulls also use their tusks to maintain territory and protect their harems.

Nicklen tried for weeks to get a close-up portrait of a male elephant seal. Because the creatures are so aggressive during breeding season, it was a dangerous endeavor. In one instance, he barely escaped death when a bull attacked him. He eventually got his

shot of this bull cooling off in fresh water in Stromness Harbour.

Elephant Seal Bulls, St. Andrews Bay During breeding season, South Georgia's beaches become battlegrounds as big elephant seal bulls engage in bloody duels for dominance. The largest of all seals, males can be over 20 feet (6 meters) long and weigh up to 8,800 pounds (4,000 kilograms).

In the water on one of his shoots.

King Penguins, Gold Harbour King penguins rinse in the surf zone of Gold Harbour on South Georgia. The island's king penguin populations are soaring. In 1925 only 1,100 kings were counted at St. Andrews Bay; since then there has been a 300-fold increase in the rookery.

Polar Bears, Svalbard A female polar bear rejects the advances of a male in Svalbard. Their stark white coats provide camouflage in surrounding snow and ice. Under the fur is black skin—the better to soak in the sun's warming rays.

Wet Polar Bear With their slightly webbed paws and powerful muscles, polar bears are excellent swimmers. Their favorite meal is seals, but they will eat anything they can catch, even scavenging through garbage in areas where their habitat overlaps with humans.

West Spitsbergen, Svalbard From 15,000 feet (4,580 meters), Spitsbergen looks inhospitable. Whalers, scientists, and Arctic explorers have used Svalbard as a base, but only 2,500 call the islands home.

Young Polar Bear, Spitsbergen A young polar bear carefully navigates a disintegrating ice pack off Spitsbergen, Svalbard. An abundance of seals keep Svalbard's polar bears fed, providing the energy necessary to keep the bears' massive bodies moving over a home range that can vary from 60 to 144,000 square miles (155 to 370,000 square kilometers).

Polar Bear Tracks, Svalbard Huge footprints reveal a polar bear's path on Svalbard. Fur grows even on the bottom of a bear's paws, protecting against cold and providing a good grip on ice.

Brünnich’s Guillemots, Bjørnøya Brünnich’s guillemots line the shore at Bjørnøya, Svalbard. These stout seabirds breed here by the hundreds of thousands, most dispersing to Iceland or Greenland in winter.

Two adult bowhead whales, each more than 45 feet in length, rest by a floe edge after diving under the ice to feed. Nicklen tells one story of accidentally parking his boat on top of a whale at night.

Parked on a whale's back, Nicklen barely escaped disaster by slowly backing up as the whale arched its back and curled its tail, dumping hundreds of gallons of water into his small boat. Rightfully overwhelmed, Nicklen did not snap a photo. But here, a bowhead whale dives to feed on copepods in Baffin Bay, Nunavut.

Polar Bear, Hornsund Strong swimmer, a polar bear takes a dip in front of a Svalbard glacier. These Arctic giants are the masters of their environment and have no natural enemies.

Hornsund, Spitsbergen A hole in glacier ice frames Hornsund, Spitsbergen. Vikings may have found the far-flung islands of Svalbard as early as the 12th century.

end

cast National Geographic Photographers: Paul Nicklen

images credit   www.          Music Oxygene - Jean Michel Jarre

created   o.e.

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