Originally uploaded to https://www.youtube.com/watch?v=OL7O5O7U4Gs by Nature on PBS To survive frigid temperatures, emperor penguins all converge on the same central point and begin to form a huddle. As those on the outside take the brunt of the cold, those on the inside take tiny steps that move the huddle in waves. The pack continues to shift and rotate from the center, so no one is left permanently in the cold. "The Gathering Swarms" premieres Wednesday, May 21, 2014, at 8/7c on PBS. For more, visit http://www.pbs.org/wnet/nature