You thought "The March of the Penguins" was cool? Check out the launch of the penguins — an aerodynamic phenomenon that helps these flightless birds take flight.
Emperor penguins can't fly just by flapping their wings, but they can propel themselves fast enough through Antarctic waters to turn themselves into winged rockets. They do it by releasing tiny bubbles of air from their feathers: The air acts as a lubricant, reducing drag as they swim up from the depths like tuxedoed torpedoes. In fact, engineers have used air bubbles in similar ways to speed the movement of torpedoes through the water.
Who knew that penguins have been doing the same sort of thing for eons? University College Cork's John Davenport knew: He and his colleagues studied video footage from the BBC's "Blue Planet" TV series to develop a biochemical model for the penguins' torpedo trick. They were amazed to find that the birds' speed was due to the "coat of air bubbles" streaming from their feathers.
Before the penguins dive into the water, they ruffle their plumage to trap air within the feathers' structure. A deep dive compresses the air into a smaller volume. When the penguins go into their launch, the decompressing air is released through pores in the feathers — creating a layer of tiny, lubricating bubbles.
The trick is described for scientists in the Marine Ecology Progress Series, and for the rest of us in November's issue of National Geographic magazine. The heart of the magazine story is Paul Nicklen's pictures, which have just won him top honors in the Environment Wildlife Photographer of the Year competition.
"We wanted to change people's perception of penguins as ungainly animals," said Nicklen, who has followed penguins and other polar species for years, and admits he's always had an obsession with Antarctica. "The biologist in me was trying to learn about the science."
And he did learn more about the biological background for the bubble trick: Penguins are preyed upon by leopard seals, which lie in wait beneath the ice to ambush the birds during their ascent from the depths. "The penguins know they're there, and as they're coming up ... it's like someone turns on a tap, and there are millions of microbubbles pouring over their bodies."
The supercharged speed helps the penguins elude their predators and shoot up to safety on the ice, Nicklen said. The masses of bubbles have another defensive effect: They confuse the seals as they try to swim in for the attack. Nicklen himself found out how that feels. When he got too close to the penguins underwater, they released a bubbly barrage.
"It was like I was floating through space, in a sea of bubbles," he said.
The online version of National Geographic's penguin spread will feature a video and interactive graphic showing in detail how the penguins rocket out of the water and onto the ice. Next week, the photographer will unveil an app called "Paul Nicklen: Pole to Pole," with more images. In the meantime, feast your eyes on these images from National Geographic, plus two bonus videos:
More about penguins:
- Penguins' graphic sexual acts shocked researcher
- Not-so-happy feet: You're stressing out the penguins
- Satellite view doubles Emperor penguin count
- Chinstrap penguin colony declines as ice and food shrink
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered via email every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.
