why do penguins huddle together to keep warm infrared

For penguins trying to survive a harsh Antarctic winter, huddling is a matter of life or death. Birds within a colony crowd together so tightly that individual movements are impossible. Collective movements are a must, however: The penguins on the periphery would die of cold if they weren't continuously being reshuffled toward the center of the crowd. But how does this constant, collective reorganization happen? How does a huddle of millions shuffle itself without crushing anyone? Physics, as it turns out. Penguins move through the huddle in the same way that sound waves propagate through a fluid only much more slowly. "Every 30 to 60 seconds, all penguins make small steps that travel as a wave through the entire huddle," writes Daniel Zitterbart, a physicist at the University of Erlangen-Nuremberg in Germany, who wrote the
along with his colleagues in the journal PLoS ONE. In a highly coordinated manner, the emperor penguins the researchers studied each took miniscule steps measuring just 2 to 4 inches (5 to 10 centimeters). "Over time, these small movements lead to large-scale reorganization of the huddle," they wrote. [Read: The traveling wave of small steps is similar to how a sound wave travels through a fluid, the researchers noted. "In general, individual penguins do not change their position relative to their neighbors, and they do not force their way in or out of a huddle. " Penguins are much better at "going with the flow" than humans, who also tend to move in waves when packed together in large, dense crowds, but sometimes end up getting crushed. "Why these waves are uncoordinated, turbulent and but not in a penguin huddle remains an open question," Zitterbart and his colleagues wrote.

If you're in stop-go traffic, you're probably pretty unhappy about it.

If you're a male penguin balancing an egg on your feet in the freezing Antarctic, that traffic jam is probably keeping you alive.

Scientists studying huddles of emperor penguins in Antarctica have discovered that waves of movement travel though huddled masses of flightless birds rather as they do through cars stuck on the freeway during rush hour - but in ways that keep the birds warm as they incubate their eggs. Emperor penguins are the only vertebrate species that breed during the Antarctic winter, and they face freezing winds that blow as fast as 200km/h in an icy landscape that can be as cold as 50 degrees Celsius below zero.

So they huddle together against the harsh elements - and together, their bodies can raise the temperature within two hours to as high as 37 degrees above zero. At first glance, the penguins may not appear to move much. The males probably can't run anywhere in a rush, in any case: The fathers-to-be cover their eggs with feathered skin known as a brood pouch, with the eggs resting on top of their feet. "If you look at a penguin huddle in real time, you hardly see any movement at all - they are all standing very still," said Richard Gerum, a physicist at University of Erlangen-Nuremberg in Germany and first author of the study published in the New Journal of Physics.

But watch this huddle of shuffling penguins long enough, and there emerge distinct waves of motion through the feathered masses as one penguin takes a step and the rest follow. It's a way of maintaining order, Gerum pointed out. "When a big human crowd is together, there can be accidents," Gerum said. "And this is something that never happens in a penguin huddle. " So although the emperor penguins don't dance like the characters in the 2006 animated film Happy Feet, they still perform some pretty fancy footwork.