Changes in surface temperatures reveal the thermal challenge associated with catastrophic moult in captive Gentoo penguins

• Main Authors: Lewden, Agnès, Du Fretay, Tristan, Halna, Stier, Antoine
• Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Leeds, 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), University of Turku
• Format: Report
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDV]Life Sciences [q-bio]; Pygoscelis papua; Sea ice
• Online Access: https://hal.science/hal-04424523; https://hal.science/hal-04424523/document; https://hal.science/hal-04424523/file/2024.01.16.575878v1.full.pdf; https://doi.org/10.1101/2024.01.16.575878

Once a year, penguins undergo a catastrophic moult replacing their en=re plumage during a fas=ng period on land or on sea-ice during which =me individuals can lose 45% of their body mass. In penguins, new feather synthesis precedes the loss of old feathers leading to an accumula=on of two feathers layers (double coat) before the old plumage is shed. We hypothesize that the combina=on of the high metabolism required for new feathers synthesis and the poten=ally high thermal insula=on linked to the double coat could lead to a thermal challenge requiring addi=onal peripheral circula=on to thermal windows to dissipate extraheat. To test this hypothesis, we measured the surface temperature of different body regions of cap=ve Gentoo penguins (Pygoscelis papua) throughout the moult under constant environmental condi=ons. The surface temperature of the main body trunk decreased during the ini=al stages of the moult, therefore sugges=ng a higher thermal insula=on. On the opposite, the periorbital region, a poten=al proxy of core temperature in birds, increased during these same early moul=ng stages. The surface temperature of bill, flipper and foot (thermal windows) tended to ini=ally increase during the moult period, highligh=ng the likely need for extra heat dissipa=on in moul=ng penguins. These results raise ques=ons regarding the thermoregulatory capaci=es of wild penguins during the challenging period of moul=ng on land in the current context of global warming.