Penguins win acclaim for outstanding strength
Dr. Michael Habib, assistant professor of biology at Chatham University, studies the wing strength of a variety of birds. Here he holds a dark green and blue emu egg from the university's collection.
A macaroni penguin swims in the tank at the Pittsburgh Zoo & PPG Aquarium.
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And you thought Pittsburgh's hockey team was named after a dumpy-looking, flightless bird.
Michael Habib offers another perspective that should please local fans.
The perception that the penguin is plump, waddling and goofy-looking is correct, but only because we analyze it based on its movements on land.
But the Stanley Cup champions and their fan base should be proud of the ice-bird moniker as a world-class swimmer.
Research by Dr. Habib, a Chatham University biologist, reveals that the penguin has the strongest wings of any bird on Earth relative to its size. Its short, robust wings make it the most efficient warm-blooded swimmer on the planet.
That fact is, it would be the Stanley Cup champion among swimming birds.
Analyzing the penguin on ice is akin to evaluating Penguin superstar Sidney Crosby off ice. Both are out of their predatory element.
Dr. Habib's study published today in the Biological Journal of the Linnean Society, analyzes wing size and strength of various bird species, with a focus on birds that also swim. To his mild surprise -- and perhaps everyone else's major surprise -- the penguin embodies one crazy conundrum:
The bird with the world's strongest wings cannot fly.
That's because penguins are built to swim. Water is a denser medium than air, so their wings must be strong, oar-like paddles to propel them through icy water. It's lemon-shaped physique actually is aerodynamic, allowing it to spear torpedo-like through water with water-resistant feathers that produce little drag.
Besides making the bird bullet-shaped, penguin fat protects it against the cold.
"If you are swimming in water, which is tough to do, your wings should be swimming wings," Dr. Habib said. "Why do penguins have super strong wings? It comes down to the fact they don't also have to fly."
Birds that swim and fly must have wings adapted to both functions, making them less efficient swimmers, due to slower wing motions and the buoyancy of feathers along with air sacks inside their bodies that require them to spend considerable energy just to remain submerged.
But penguins use less oxygen per unit of distance traveled than any other swimming bird, giving them best mileage. They can dive as deep and swim as fast as dedicated warm-blooded marine animals including some dolphins.
And yet, they also can walk on land.
Penguins, he said, dive deeper at higher speeds and stay underwater longer than any other swimming bird. Puffins, another swimming bird, "can't hold a candle to a penguin" and not only because water would extinguish said candle.
"There does seem to be an advantage to giving up flight," Dr. Habib said. "It makes the penguin a better swimmer. My conclusions allow them to supersize their muscles and wing strength with heavy, thick bones."
Bird wing bones typically are lightweight. But a penguin's wing bone "feels like a rock," Dr. Habib said.
"It's solid all the way through. There's no space left in the bone. Our bones have marrow but their bones have almost no marrow. They are strong and solid. That's not conducive to flying, but it is conducive to swimming. It makes them heavy and helps them to dive."
For a moment, forget the Sidney Crosby comparison and consider the penguin as the Michael Phelps of warm-blooded swimmers.
Their small but powerful wings get equal push from the upstroke and downstroke, which puts more rigor on muscles and bones. But that's why the penguin is so stout. It's vast chest and shoulder muscles help propel its 40-plus pounds efficiently through water.
"Its musculature and extra layer of fat -- smooth extra fat so it can live in cold water -- makes it streamlined with a very low drag coefficient," Dr. Habib said. "The drag is lower than expected due to feather structures that create little friction in the water."
Dr. Habib said he realized before doing the study that penguins had strong swimming wings but thought their wing strength would be similar to other wing-propelled swimming birds, including puffins and auks.
"I didn't think the gap between them would be that big," he said. "But there's a huge difference."
Dr. Habib calculated the biomechanical strength of penguins and other birds, including birds that don't swim. His work advances the research on penguins with new details about how penguins swim and, thus, behave.
It also proves that penguins, which are "hugely different" from other swimming birds, represent a unique evolutionary line that included penguin-like prehistoric birds that stood 6 feet tall and weighed hundreds of pounds.
The present-day birds stand tall in athletic ability, even exceeding humans.
Dr. Habib describes the lower-case penguin as "the prince of the warm-blooded swimming world."
First Published March 31, 2010 12:00 am