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, Théry, 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), DACE, University of Glasgow, Sea Mammal Research Unit, St Andrews, 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 - 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.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; [SDV.BDLR.RS]Life Sciences [q-bio]/Reproductive Biology/Sexual reproduction; [SDV.EE.IEO]Life Sciences [q-bio]/Ecology; environment/Symbiosis; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; environment/Ecosystems; Wallows; Elephant Seal; Elephant Seals; Mirounga leonina; Southern Elephant Seal; Southern Elephant Seals
• Online Access: https://hal.science/hal-02889417; https://hal.science/hal-02889417/document; https://hal.science/hal-02889417/file/Chaise%20et%20al_determinants%20of%20huddling%20behabior_Physiol%20Behav%202018.pdf; https://doi.org/10.1016/j.physbeh.2018.10.016

International audience While endotherms can rely on their insulation to reduce heat loss to adapt to cold environments, renewing of fur during molt impairs insulation while they have to perfuse the periphery to support epidermal tissues. 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. Infrared thermography and stomach temperature loggers were used to observe variation in body surface and internal temperature in relation to molt stage and aggregation behavior. We found that thermal constraints varied during the molt, with a peak in surface temperature during the mid-stage of the molt. Wallows (mud pools) appear as favorable habitat to aggregate while molting. Indeed, wallows offered a warmer microclimate with greater 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 were located in the center of the aggregation, and larger group size occurred during days of unfavorable meteorological conditions. We also observed a higher proportion of seals at mid-stage of molt amongst aggregated seals compared to isolated individuals. This aggregation behavior may reduce the cost of thermogenesis as surface body temperature and stomach temperature were cooler by 1.0 °C and 1.5 °C, respectively, in aggregated compared to isolated seals. As a consequence, huddling behavior may be thermally advantageous for female southern elephant seals during the molt.