Coordinated Movements Prevent Jamming in an Emperor Penguin Huddle

For Emperor penguins (Aptenodytes forsteri), huddling is the key to survival during the Antarctic winter. Penguins in a huddle are packed so tightly that individual movements become impossible, reminiscent of a jamming transition in compacted colloids. It is crucial, however, that the huddle structu...

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Bibliographic Details
Published in:PLoS ONE
Main Authors: Zitterbart, Daniel P., Wienecke, Barbara, Butler, James P., Fabry, Ben
Format: Text
Language:English
Published: Public Library of Science 2011
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3106014
http://www.ncbi.nlm.nih.gov/pubmed/21673816
https://doi.org/10.1371/journal.pone.0020260
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Summary:For Emperor penguins (Aptenodytes forsteri), huddling is the key to survival during the Antarctic winter. Penguins in a huddle are packed so tightly that individual movements become impossible, reminiscent of a jamming transition in compacted colloids. It is crucial, however, that the huddle structure is continuously reorganized to give each penguin a chance to spend sufficient time inside the huddle, compared with time spent on the periphery. Here we show that Emperor penguins move collectively in a highly coordinated manner to ensure mobility while at the same time keeping the huddle packed. Every 30–60 seconds, all penguins make small steps that travel as a wave through the entire huddle. Over time, these small movements lead to large-scale reorganization of the huddle. Our data show that the dynamics of penguin huddling is governed by intermittency and approach to kinetic arrest in striking analogy with inert non-equilibrium systems, including soft glasses and colloids.