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Nat Commun 2 (2011) 435
Heterothermy in growing king penguins.
Götz Eichhorn1, René Groscolas1, Gaële Le Glaunec1, Camille Parisel2, Laurent Arnold2, Patrice Medina2, Yves Handrich1

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.
1 :  DEPE-IPHC - Département Ecologie, Physiologie et Ethologie
2 :  DRS-IPHC - Département Recherches Subatomiques
Sciences de l'environnement