Washington, October 21: Emperor penguins propel through the water by releasing air from their feathers in the form of tiny bubbles, a team of scientists has found.
When Roger Hughes, marine biologist at Bangor University in north Wales, saw emperor penguins in a BBC documentary, rocketing through the sea with trails of bubbles in their wakes, he had an insight that would lead to a surprising discovery.
Hughes first thought that those bubbles help penguins swim faster, as reported by National Geographic Magazine.
Hughes and his friend John Davenport, a marine biologist at University College Cork in Ireland, combed the scientific literature and found that the phenomenon had never even been studied. So they decided to do it themselves.
With the help of Poul Larsen, a mechanical engineer at the Technical University of Denmark, they analysed hours of underwater footage and discovered that the penguins were doing something that engineers had long tried to do with boats and torpedoes: They were using air as a lubricant to cut drag and increase speed, according to the magazine.
When an emperor penguin swims through the water, it is slowed by the friction between its body and the water, keeping its maximum speed somewhere between four and nine feet a second.
But in short bursts the penguin can double or even triple its speed by releasing air from its feathers in the form of tiny bubbles. These reduce the density and viscosity of the water around the penguin’s body, cutting drag and enabling the bird to reach speeds that would otherwise be impossible. (As an added benefit, the extra speed helps the penguins avoid predators such as leopard seals.)
The key to this talent is in the penguin’s feathers. Like other birds, emperors have the capacity to fluff their feathers and insulate their bodies with a layer of air.
But whereas most birds have rows of feathers with bare skin between them, emperor penguins have a dense, uniform coat of feathers. And because the bases of their feathers include tiny filaments-just 20 microns in diameter, less than half the width of a thin human hair-air is trapped in a fine, downy mesh and released as microbubbles so tiny that they form a lubricating coat on the feather surface.
Though feathers are not an option for ships, technology may finally be catching up with biology. (ANI)