The team's mathematical models showed that the huddles behave as waves instigated by any individual in the pack, no matter that individual's location. If two waves travel toward each other, they merge, rather than passing one another. Gaps just 2 centimeters wide (0.8 inches) appear to instigate a reorganization, in order for the penguins to stay warm, the team reports today (Dec. 16) in the New Journal of Physics.
Why penguins move so frequently and in such small steps remains unclear, though the researchers think the shuffles may help the birds rotate their eggs to keep them warm.
"It might be that the egg can get cold at the bottom and so the penguins have to rotate the egg every now and then," Gerum said. "This is just a speculation."
Emperor penguins are the only vertebrates on the Antarctic continent that breed during the coldest months of the year.
While the model that the researchers created has the penguins moving in a straight line, the natural formation of the huddles often moves more in a spiral rotation, Gerum said. Next, the team hopes to create a mathematical model that recreates this more complicated rotational movement.
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