[Energy metabolism of the king penguin chick - Aptenodytes patagonicus (J.F. Miller) - during growth (author's transl)].

The growth of the subantarctic King penguin chick is distinguished from that of other penguins by its long winter fasting period (from 2 weeks to 3 months). From the moment of hatching the unfledged chicks are brooded by their parents until they are able to maintain their own body temperature. Body temperature increases gradually from 34.3 degrees C after hatching to 39.2 degrees C by about 20 days of age; measured air temperature (Ta) was 16 degrees C on average. Unlike antarctic Penguins, homeothermy and full emancipation does not occur at the same time. This suggests that emancipation may be determined by insulation after thermogenesis mechanisms have become efficient. Close to 90 kcal.kg-1.day-1 after hatching (Ta = 15.8 +/- 3.6 degrees C), the resting metabolic rate increases by 125% during the first three days and then decreases progressively; this appears to be linked with insulation generated by the down. By two months of age, the resting metabolic rate reaches 47 kcal.kg-1.day-1 on average for Ta = 4.3 +/- 1.4 degrees C and then does not evolve significantly until the moult.