title: Heterothermy in growing king penguins.
abstract: A drop in body temperature allows significant energy savings in endotherms, but facultative heterothermy is usually restricted to small animals. Here we report that king penguin chicks (Aptenodytes patagonicus), which are able to fast for up to 5 months in winter, undergo marked seasonal heterothermy during this period of general food scarcity and slow-down of growth. They also experience short-term heterothermy below 20 °C in the lower abdomen during the intense (re)feeding period in spring, induced by cold meals and adverse weather. The heterothermic response involves reductions in peripheral temperature, reductions in thermal core volume and temporal abandonment of high core temperature. Among climate variables, air temperature and wind speed show the strongest effect on body temperature, but their effect size depends on physiological state. The observed heterothermy is remarkable for such a large bird (10 kg before fasting), which may account for its unrivalled fasting capacity among birds.
authors.affiliation: Université de Strasbourg, IPHC-DEPE, 23 rue Becquerel, Strasbourg 67087, France. goetz.eichhorn@c-strasbourg.fr
authors.forename: Götz
authors.initials: G
authors.lastname: Eichhorn
authors.forename: René
authors.initials: R
authors.lastname: Groscolas
authors.forename: Gaële
authors.initials: G
authors.lastname: Le Glaunec
authors.forename: Camille
authors.initials: C
authors.lastname: Parisel
authors.forename: Laurent
authors.initials: L
authors.lastname: Arnold
authors.forename: Patrice
authors.initials: P
authors.lastname: Medina
authors.forename: Yves
authors.initials: Y
authors.lastname: Handrich
mesh_terms: D000818:Animals; D001831:Body Temperature; D001833:Body Temperature Regulation; D003080:Cold Temperature; D005215:Fasting; D005260:Female; D008297:Male; D012621:Seasons; D046429:Spheniscidae / Q000254:growth & development / Q000502:physiology*