Maybe it's their endearing waddle. Maybe it's their seemingly analytical gaze. Or maybe it's their absurd, tuxedolike formality.
Whatever the explanation, there's no denying that penguins are one of the most intriguing, enchanting species on earth.
"They're comical, they're endearing and this is a spectacle of nature," Dee Boersma, one of the world's leading penguin experts, said as she sat recently on an Argentine beach surrounded by thousands of penguins. "You don't see many spectacles like this anywhere in the world."
The spectacular Punta Tombo Peninsula in Argentina's Patagonia region is home this time of year to half-a-million Magellanic penguins, the largest colony of these 2½-feet-tall penguins in the world.
For pictures of the Punta Tombo penguins, click HERE.
The area is also home to Boersma this time of year. The University of Washington biologist has been coming here for almost 30 years to conduct one of the longest-continual studies of penguins anywhere.
She has banded more than 60,000 penguins in her three decades here.
"OK," she said as she walked along the beach, counting penguins with a clicker in her palm, "so I just looked at 152 birds and one of them's got a band."
Boersma has tracked generations of penguins and documented an alarming decline in the penguin population here.
"I mean that when penguins aren't doing well, they're telling us that our world isn't doing well," she said.
Boersma is one of the world's leading experts on the quirky creatures. In the process, she has also become an expert on penguin romance. She even offers a play-by-play of the penguin mating ritual.
"He's courting, he's trying to get this female to pay attention to him," she said with a grin, watching an awkward male try to get the attention of an indifferent female.
Penguin fidelity patterns are remarkably evocative of another species, one we know quite well, Boersma said.
'Really High Fidelity'
"We 've had some pairs that have stayed together for 16 years, so that's really high fidelity," she said. "They're monogamous, but they're not necessarily faithful, particularly if they fail to raise their eggs or their chicks. Then they're much more likely to divorce in the next year."
By late afternoon, strange sounds punctured the air. It sounded like a donkey but it's penguins, just returned from a fishing expedition. It's no accident that early settlers called them jackass penguins.
"That noise that you're hearing, a couple has just come back, so one of the pair was gone, and they've just returned," Boersma explained, with a mischievous grin. "So that's the greeting. 'Hi honey, I'm home.'"
The penguins, which have been out fishing, come in for a landing at the water's edge.
As the sun starts to set -- very late in the day this far south at this time of year -- the beaches of Punta Tombo fill with wet, weary penguins.
The penguins are arriving, but it's hard to tell whether they're just playing around in the surf or coming from somewhere. "They're coming back to feed their chicks," the noted penguiphile said. "They've been gone for several days, and they're coming back so fat because they've got to bring back fish to be able to feed their two chicks."
They fill their bellies with fish and then they regurgitate it.
"So, basically, the parents are the refrigerators and they come back storing the fish inside and then they regurgitate to the chicks and that's how they grow," Boersma said.
'They Pay for It Physically'
Boersma knows exactly how far penguins travel in search of fish for their chicks: on average, about 93 miles away from the colony.
She tracks her penguins by satellite. The birds travelled pretty far this year, she said.
Scientists used to think that penguins ventured 20 or 30 miles offshore to feed. But Boersma discovered that they can swim hundreds of miles on a foraging trip.
"The fastest we've had a satellite-tagged bird go is 173 kilometers [about 107 miles] in a day, so 24 hours" she said.
One penguin, which Boersma called Dan, was at sea for two weeks in November 2007. He swam more than 850 miles, filling his belly with fish as he waited for his chicks to be born.
Satellite tracking has found in recent years that the birds have been traveling farther in search of fish during the critical days when their chicks need constant feedings, she said.
"I can follow them at sea," Boersma said, "and so we know that in the last decade, the last 10 years, they're going about 40 kilometers further, so 25 miles further now than they did 10 years ago. ... You've got to swim it back too, so that's another 50 miles.
"How much does your gas cost for your car? These guys have got to pay for the cost in terms of having more fish, and more time away. So they pay for it physically."
After the chicks are born, the trips can't last more than two or three days, which concerns Boersma. Her research has found that even in this pristine, remote stretch of ocean, penguins are having to go farther and farther to fill their bellies with food for their chicks.
Boersma has found that the parents are coming back later, with less fish in their bellies.
She walked in an area of rolling sand dunes filled with thousands of penguin nests. A female penguin sat at her feet next to a dead chick.
"It's too bad, like look at this one, she's already lost her chicks," Boersma said as she picked up the dead baby. The mother penguin came back from fishing too late.
"He had to eat sooner than she came home."
And while scenes like this will always happen in nature, Boersma's annual census of the penguin population concluded that it is down about 20 percent in 25 years.
"They're having to travel farther to find the food," Boersma said. "The food's just not here. And part of that is climate change. It changes the distribution of prey and it changes then where the penguins have to go to find it. ... It's not as good fishing as it used to be because, of course, we're Hoover-vacuuming the oceans for food for us.
"We're fishing down the food chain and so you're seeing more and more anchovies, sardines for sale. We're eating penguin food, more and more. ... Because the big fish are gone from the oceans. We've already eaten those."
But there are still a lot of Magellanic penguins to be seen here and elsewhere along the coasts of South America.
"This is the 'zona mas densa,'" Boersma said as she surveyed an area dense with penguins, "So this is a high-density area, and what you're seeing here is the real estate where penguins can dig real deep boroughs. This is the best-quality nesting. ... Everybody wants to live here. This is about 12,000 pairs right in this area."
But 12 of the world's 18 penguin species are listed as either threatened or endangered as their habitat is destroyed, their food disappears and warming oceans threaten their survival.
"Penguins are sentinels. I see them as global sentinels," Boersma said. "They're telling us what's happening on land as well as in the water."
Boersma knelt down to look at a penguin pair she's been tracking for years. A penguin waddles up beside her, looks at her curiously, then grabs for her pen. Boersma can't resist a laugh.
It is easy to share her fascination with these endlessly entertaining creatures. But while the science here has some obvious -- and charming -- dividends, it is serious.
Through the science, Boersma said, the penguins are telling us something about the planet we share, and that we need to listen to them.