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How Giant Birds Can Fly Nearly 10,000 Miles in One Go  

发现者:lylillian 来源: 发布时间:2013-11-14 类型:转载
Photo of giant albatross preparing to land in nest.

A wandering albatross lands at a nest site on South Georgia Island, Antarctica. Photograph by Paul Souders, Corbis.

Forget circumnavigating the globe in 80 days—an albatross can do it in a mere 46!

These world travelers are among the largest flying birds, weighing up to 25 pounds (11 kilograms), and with a wingspan of 11 feet (3 meters). But hefting such huge bodies off the ground takes a lot of energy. If albatrosses flew simply by flapping their wings, they would lose about half their body mass fueling that kind of flight.

So how do these kings of the sky complete such long journeys so quickly? It turns out they glide in a specific flight pattern that allows them to harness wind energy, gliding right above the sea’s surface to stay aloft, according to a study published in the Journal of Experimental Biology.

Coasting Through Life

A team of scientists from the Technische Universitat Munchen in Munich, Germany, used aerospace engineering to reveal the birds’ unique flight patterns—a physical feat that has puzzled academics for years. By attaching GPS trackers to 20 wandering albatrosses (Diomedea exulans) in the wild, the researchers were able to study data from 16 of the birds as they left and returned to the Kerguelen Archipelago (map) in the Indian Ocean.

Albatrosses yo-yo up and down in the sky, taking advantage of momentum generated on their downhill glides in order to climb back up against the wind. These constant up and down changes in altitude keep the birds aloft without requiring much effort. In fact, the propulsive force generated by such undulations is about ten times greater than anything the albatross could create by simply flapping its wings.

Working Harder, Not Smarter

But it’s a trick the rest of the animal kingdom doesn’t often use. For example, hummingbirds weigh about 0.07 ounces (2.2 grams)—98 percent less than an albatross—and yet their wings have to beat about 70 times per second to keep their little bodies aloft. An albatross can go hours without flapping. Because of this frantic motion, hummingbirds have to eat up to three times their body weight every day.

Even humans struggle with energy efficiency. “An elite cyclist at 60 percent of his maximum aerobic rate can only support 15 to 30 percent of his energy needs with consumed sugars,” according to a LiveScience article. That means we have to refuel more often than the albatross, which can travel greater distances without working as hard.

While it took Jules Verne’s characters just over two and a half months to circumnavigate the globe, an albatross can do it in about half the time. Phileas Fogg and his trusty sidekick Passepartout just can’t compete with these fantastic flyers!

   
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