Penguins have a unique way of keeping warm as they battle harsh Antarctic conditions, a new study suggests.
Scientists found that emperor penguins stay in a tight huddle to protect themselves from the harsh winter. The findings, published in the New Journal of Physics, describe how the penguins use stop-and-go movements much like cars in a traffic jam to battle the elements.
Biologists and physicists based at the University of Erlangen-Nuremberg in Germany had previously identified how emperor penguins form a huddle that moves every 30 to 60 seconds.
This new study expanded on the findings where scientists used a mathematical model to recreate how individual penguins move inside the group. The study found that a penguin only needs to move 2 centimeters in order for its neighbor penguin to react and move closer.
"That means a perfectly compact huddle tries to maintain each bird's maximum fluffiness and insulation," co-author of the study Daniel Zitterbart, of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, told New Scientist.
Each of these movements makes the entire huddle resemble a wave that guards the penguins from the cold.
"Our previous study showed how penguins use travelling waves to allow movement in a densely packed huddle, but we had no explanation as to how these waves propagate and how they are triggered," Zitterbart said.
Researchers used a mathematical model, previously used to study traffic jams, to monitor the penguins’ movements and compared them to video recordings of penguin huddles. Researchers found that the wave can begin from the movement of a single penguin and propagate in any direction.
"We were really surprised that a travelling wave can be triggered by any penguin in a huddle, rather than penguins on the outside trying to push in," Zitterbart said. "We also found it amazing how two waves, if triggered shortly after each other, merged instead of passing one another, making sure the huddle remains compact."
While Zitterbart’s findings explains what triggers emperor penguins to move in the huddle, the team is still left wondering why an individual penguins shifts altogether.
“Right now we speculate that the penguins might use this technique to be able to rotate their eggs -- which they can’t with their beak, [so] it would make sense for a penguin to start movement even if he is right inside the huddle,” Zitterbart told Scientific American.
Unlike other penguin species, male emperor penguins carry the sole responsibility of incubating an egg during the winter, which can drop to -58 Fahrenheit. Male penguin huddles consisting of thousands form to maintain their body temperatures.