This video, from Nature and Scientific American shows how Emperor penguins use physics to avoid crush and keep warm. The video is sped up to show subtle movement patterns throughout the mob that manages the feat. Mobs of all sorts may have lessons to be learned from how these birds survive crushing cold without crushing each other. The article explains:
In the sped-up video, they could see that the “Emperor penguins move collectively in a highly coordinated manner to ensure mobility while at the same time keeping the huddle packed,” the researchers noted in a new study, which published online Wednesday in PLoS ONE. “Every 30-60 seconds, all penguins made small steps that travel as a wave through the entire huddle. Over time these small movements lead to large-scale reorganization of the huddle.” And the reshuffle takes time, with each step measuring just five to 10 centimeters.
The wave pattern was not unlike that of a a sound wave traveling through a fluid, pointed out the research team, which was led in part by Daniel Zitterbart, of the Department of Physics at the University of Erlangen-Nuremberg in Germany. “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,” they noted.
In dense crowds, people also tend to move in waves. But we are not so orderly, which often leads to chaotic crushes and occasionally death. “Why these waves are uncoordinated, turbulent and dangerous in a human crowd but not in a penguin huddle remains an open question,” . . . .