Environmental and physiological determinants of huddling behavior of molting female southern elephant seals (Mirounga leonina)

• Published in: Physiology & Behavior
• Main Authors: Chaise, Laureline, Mccafferty, Dominic, Krellenstein, Adélie, Gallon, Susan, Paterson, William, Thery, Marc, Ancel, André, Gilbert, Caroline
• Other Authors: Mécanismes Adaptatifs et Evolution (MECADEV), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), University of Glasgow, Scottish Oceans Institute, University of St Andrews Scotland, 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), École nationale vétérinaire d'Alfort (ENVA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: stomach temperature; meteorological variations; phocids; aggregation behavior; heat loss; habitat type; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; Wallows; Elephant Seal; Elephant Seals; Mirounga leonina; Southern Elephant Seal; Southern Elephant Seals
• Online Access: https://hal.archives-ouvertes.fr/hal-02108299; https://hal.archives-ouvertes.fr/hal-02108299/document; https://hal.archives-ouvertes.fr/hal-02108299/file/PHB_2018_3_Original_V0.pdf; https://doi.org/10.1016/j.physbeh.2018.10.016

International audience Thermoregulation is particularly costly for homeotherms living in extreme environmental conditions. The southern elephant seal Mirounga leonina undertakes an annual catastrophic molt while fasting on land in a wet, windy and cold environment. However, southern elephant seals show characteristic aggregation patterns that are predicted to reduce high metabolic costs during the molt. Between 2012 and 2016, 59 female elephant seals were tracked on land during their molt to study their aggregation behavior in relation to molt stage, habitat type and local weather conditions. Nine seals were equipped with stomach temperature loggers and infrared thermography was used to observe variation in body and surface temperature, respectively, in relation to molt stage and aggregation behavior. We found that thermal constraints varied during the molt, with a peak in surface temperature during mid-stage of the molt. Wallows (mud pools) appear as favorable habitat to aggregate while molting. Indeed, wallows offered a warmer microclimate with higher ground temperature and lower wind speed. Moreover, there was a greater proportion of aggregated seals and larger group size in wallows. These aggregation patterns in wallows were influenced by local weather such that a greater proportion of seals positioned in the center of the aggregation, and larger group size occurred during days of unfavorable meteorological conditions. We also observed that elephant seals aggregated more during the mid-stage of molt. This aggregation behavior may reduce the cost of thermogenesis as surface body temperature and stomach temperature were lower in aggregated compared to isolated seals by 1.0°C and 1.5°C, respectively. Huddling behavior was therefore thermally advantageous for female southern elephant seals during the molt. Further work is needed to better understand physiological mechanisms linked to different huddling strategies. File Name [File Type] cover-letter_Chaise_P&B.pdf [Cover Letter] ...