The origin of traveling waves in an emperor penguin huddle

• Main Authors: Gerum, R.C., Fabry, B., Metzner, C., Beaulieu, Michael, Ancel, André, Zitterbart, D.P.
• Other Authors: Department of physics, Friedrich-Alexander Universität Erlangen-Nürnberg = University of Erlangen-Nuremberg (FAU), Department of Evolutionary Biology and Animal Ecology, University of Freiburg Freiburg, Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDE]Environmental Sciences; [SDV]Life Sciences [q-bio]; [PHYS.PHYS.PHYS-DATA-AN]Physics [physics]/Physics [physics]/Data Analysis; Statistics and Probability [physics.data-an]; Antarctic; Huddle; The Antarctic; Antarc*; Emperor penguins
• Online Access: https://hal.science/hal-00925832; https://hal.science/hal-00925832/document; https://hal.science/hal-00925832/file/1367-2630_15_12_125022.pdf; https://doi.org/10.1088/1367-2630/15/11/000000

International audience Emperor penguins breed during the Antarctic winter and have to endure temperatures as low as −50 C and wind speeds of up to 200 km h−1. To conserve energy, they form densely packed huddles with a triangular lattice structure. Video recordings from previous studies revealed coordinated movements in regular wave-like patterns within these huddles. It is thought that these waves are triggered by individual penguins that locally disturb the huddle structure, and that the traveling wave serves to remove the lattice defects and restore order. The mechanisms that govern wave propagation are currently unknown, however. Moreover, it is unknown if the waves are always triggered by the same penguin in a huddle. Here, we present a model in which the observed wave patterns emerge from simple rules involving only the interactions between directly neighboring individuals, similar to the interaction rules found in other jammed systems, e.g. between cars in a traffic jam. Our model predicts that a traveling wave can be triggered by a forward step of any individual penguin located within a densely packed huddle. This prediction is confirmed by optical flow velocimetry of the video recordings of emperor penguins in their natural habitat.