How Penguins Lost Their Ability to Fly
July 23, 2012 --
This week Google debuted a new set of panoramic images from the South Pole. Taken in partnership with on-site researchers from the University of Minnesota’s Polar Geospatial Center, these interactive views shed light on remote locations such as Ernest Shackleton’s early shelter and the Adélie penguin rookery. The images were captured using off-the-shelf equipment that included a digital SLR camera with a fisheye lens, said Alex Starns, a Google technical program manager for Street View whose work covers operations in Asia Pacific and Antarctica. Brad Harried, a researcher with the Polar Geospatial Center, took the latest photos. “Brad would often carry extra batteries in his pocket and use a chemical hand warmer to keep them from freezing,” Starns said. “It’s a little challenging to operate the camera wearing thick winter clothes and mittens.” Explore the frigid Antarctic landscape in this slide show of high-resolution images.
The South Pole Telescope building shown here contains an enormous scientific instrument that took more than 30 engineers and scientists to construct. “The South Pole Station is actually at a really high altitude,” Starns said. Located 1.7 miles above sea level, the telescope is used by a team of scientists seeking to answer crucial questions such as “How old is the universe?” Since the South Pole has such clear atmosphere, it’s an ideal location for observing the thermal radiation that fills our universe. Starns hopes that Street View users who interact with the new images from Antarctica will be excited to learn more about the continent. He also wants them to have a greater appreciation for the explorers of 100 years ago and modern researchers, he said. Particularly the challenges inherent in a place NASA scientists used to prepare the landers for conditions on Mars. ANALYSIS: 100 Years Ago Today: Scott Reaches South Pole
Anglo-Irish explorer Ernest Shackleton survived what seemed like certain death. His first attempt to reach the South Pole in 1901 nearly killed him. In 1908 he returned, getting even closer to the South Pole. Although Norwegian explorer Roald Amundsen got there first in 1911, Shackleton was still determined. His ship Endurance would get trapped in the ice, forcing the crew on an epic adventure to safety. New images show the entire interior of Shackleton’s 1908 hut at Cape Royds. “Having this immersive imagery of the supply depot they built really reinforces the sense of just how incredible that journey was,” Starns said. Reading materials remain on the beds, tossed aside as if their owners will be back momentarily. And yet the objects inside hut have stayed in place for more than a century. “His
was unique because they had some early photographic equipment on board,” Starns said of Shackleton. “In the hut you can still see some of the photographic chemicals that they used to develop their film.” Photographer Frank Hurley’s images from the Endurance expedition would become famous. HOWSTUFFWORKS: Can You Vacation in Antarctica?
A 50-foot-long wooden cabin was built in 1911 at Cape Evans on Ross Island to house several dozen men. British explorer Robert Falcon Scott used this building as a base for his Terra Nova expedition to the South Pole, but he and his team ultimately reached the pole weeks after Amundsen. Scott and the four other men in his party died in the frozen wilderness while attempting to return. A letter found with his body read, "Had we lived, I should have had a tale to tell of the hardihood, endurance, and courage of my companions which would have stirred the heart of every Englishman." Although the cabin has remained largely unchanged since Shackleton locked it up in 1917, scientists have to regularly keep it from being swallowed by ice and snow. "You look at the food and the equipment that they brought and imagine how isolating and how lonely it must have been down there," Starns said, adding that he couldn’t imagine spending years eating tea biscuits and gravy. "It’s amazing to me that not only did these men do this, but many of them volunteered for it." NEWS: Two Aussies Reach South Pole Unaided
Back in 2010, Google first unveiled Street View images taken from Half Moon Island on the northern edge of the Antarctic Peninsula. Visitors from cruise ships that stopped there helped take the panoramic photos at the time, Starns said. Instead of a human, the Street View icon turned into a little penguin. The Adélie penguins at a remote rookery on Cape Royds aren’t accustomed to humans taking their pictures, but they seem more focused on soaking up the summer sun. From here the waters of McMurdo Sound are visible. Adélie penguins use the sun to navigate from land to the sea, according to scientific data from the Polar Conservation Organization. Unlike the humans in Google’s shots, none of the penguins have blurred faces to protect their identities. “If we get any blurring requests from them, we’ll be sure to tend to them,” Starns joked. ANALYSIS: Paralyzed Athlete Sit-Skis to the South Pole
Flags from the nations that signed the Antarctic Treaty encircle the Ceremonial South Pole. In 1959 the original treaty among 12 nations included provisions stating that Antarctica would only be used for peaceful purposes and ensuring continued scientific research there. Since then, the list of signatories has grown to 50. Besides flags, the Ceremonial South Pole is marked by a pedestal with a reflective globe on top. In the background stands the Amundsen-Scott South Pole Station, an American scientific facility. When the Google panoramic images were shot on the polar plateau, the conditions weren’t just windy -- the temperature was negative 60 degrees F. The ice that the station is built on moves annually so the geographic South Pole location is in a different position every year, Starns said. "The ceremonial pole always stays in the same place." VIDEO: Frozen Planet: Journey to the South Pole
Penguins lost their ability to fly millions of years ago, and now a new study explains why -- the birds became lean and mean diving machines, trading flight for such skills.
The study, published in the latest Proceedings of the National Academy of Sciences, points out that good flippers don’t fly very well.
"Once penguins gave up flight, changes to wing structure and overall body size and shape probably followed rapidly because flying no longer placed constraints to body form," co-author Robert Ricklefs told Discovery News.
"Note that penguins are much more at risk of predation in the water than they are on land, and so there has been strong selection to make their swimming and diving as efficient as possible," added Ricklefs, who is a professor of biology at the University of Missouri at St. Louis.
Ricklefs, lead author Kyle Elliott and their team at first wondered why the ubiquitous black and white birds lost their ability to fly millions of years ago, given how beneficial flying can be. Emperor penguins laboriously walk over 32 miles between their rookeries and the sea. The journey takes them several days, which could be reduced to just a few hours if they could fly. Why then don’t they?
To solve the mystery, the researchers focused on birds-- especially the murre -- that both fly and dive. The scientists equipped 41 such wild-caught birds with equipment to measure avian energy expenditure. In doing so, the researchers came up with a new world’s record. Murres and pelagic cormorants turn out to have the highest expenditure ever recorded for any flying animal.
"The costs are incurred in providing lift in air," Ricklefs explained, adding that overcoming drag in the air is also energy costly to the birds.
While murres can both fly and dive, there appears to be a threshold where one activity overtakes the other in evolution. If a bird needs to fly more, it will lose more of its diving and swimming ability. Conversely, if a bird greatly relies upon swimming and diving for its hunting and survival, then it will tend to lose its flight skills. In the case of penguins, those skills completely disappeared, with the wings evolving into marine mammal-type flippers.
The study also sheds light on what prehistoric flying penguins looked and acted like.
"The flying ancestors of penguins were probably not much different in general appearance than murres and their relatives, and probably behaved in much the same way," Ricklefs said.
The findings could help explain how other birds lost their ability to fly. There is a flightless cormorant in the Galapagos Islands, and steamer ducks of the southern oceans are also flightless.
The reasons for flightlessness are different for ostriches and emus, which do not dive. These big birds instead traded flight for running ability. It’s likely that the ancestors of ostriches and emus did not have to migrate. They perhaps lived in the southern continents with relative few predators. Running with their powerful legs sufficed, versus needing to rely upon flight to take them up and away.
Tony Diamond of the University of New Brunswick, James Lovvorn at Southern Illinois University, and Daniel Roby of the Department of Fisheries and Wildlife all told Discovery News that they agree with the conclusions of the new study.
Diamond said the study "draws on the unique diversity of mobility-modes in birds -- walking, running, swimming, flying -- to clarify and explain evolutionary patterns that are otherwise puzzling."
Rory Wilson of Swansea University, had a more measured response, saying the authors of the study "are probably right, but the result would be more definitive if they compared auks with diving ducks." He explained that some birds have very different types of plumage that can affect heat loss. Heat loss, in turn, can affect the bird’s energy costs when flying and diving.