New insights into the huddling dynamics of emperor penguins

• Published in: Animal Behaviour
• Main Authors: Ancel, André, Gilbert, Caroline, Poulin, Nicolas, Beaulieu, Michaël, Thierry, Bernard
• Other Authors: Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Vétérinaire Maisons-Alfort, Institut de Recherche Mathématique Avancée (IRMA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Zoological Institute & Museum, Universität Greifswald - University of Greifswald, IPEV
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: aggregation; Antarctica; aptenodytes forsteri; energy saving; environment; huddling; social thermoregulation; geo; envir; Antarctic; Huddle; The Antarctic; Antarc*; Aptenodytes forsteri; Emperor penguins
• Online Access: https://doi.org/10.1016/j.anbehav.2015.09.019; https://hal.archives-ouvertes.fr/hal-01253590

International audience Social thermoregulation is a cooperative strategy in which animals actively aggregate to benefit from thewarmth of conspecifics in response to low ambient temperatures. Emperor penguins, Aptenodytes forsteri,use this behaviour to ensure their survival and reproduction during the Antarctic winter. An emperorpenguin colony consists of a dynamic mosaic of compact zones, the so-called huddles, included in alooser network of individuals. To maximize energy savings, birds should adjust their huddling behaviouraccording to environmental conditions. Here, we examined the dynamics of emperor penguin aggregations,based on photo and video records, in relation to climatic factors. Environmental temperature,wind and solar radiation were the main factors contributing to huddle formation. The analysis of individualmovements showed that birds originating from loose aggregations continually joined huddles.Sometimes, a small number of birds induced a movement that propagated to the entire huddle, causingits breakup within 2 min and releasing birds, which then integrated into looser aggregations. Differentparts of the colony therefore appeared to continually exchange individuals in response to environmentalconditions. A likely explanation is that individuals in need of warmth join huddles, whereas individualsseeking to dissipate heat break huddles apart. The regular growth and decay of huddles operates aspulses through which birds gain, conserve or lose heat. Originally proposed to account for reducingenergy expenditure, the concept of social thermoregulation appears to cover a highly dynamic phenomenonthat fulfils a genuine regulatory function in emperor penguins.