Steen J B, Gabrielsen G W
Department of Biology, University of Oslo, Norway.
Acta Physiol Scand. 1988 Apr;132(4):557-61. doi: 10.1111/j.1748-1716.1988.tb08365.x.
Oxygen consumption (VO2), body temperature (TB) and electric muscle activity (EMG) were measured at varying ambient temperatures (TA) in common eider ducklings from the eggs pipped to 1 day after hatching. Eggs at pipping and ducklings still wet from hatching doubled their VO2 at TA = 2-4 degrees C compared with TA = 27 degrees C, but were unable to maintain constant TB. Increased EMG activity was recorded from ducklings 30 min after hatching. Artificially dried 1-h-old ducklings maintained normal TB (39.0-40.5) for at least 90 min at TA = 2 degrees C. Ducklings older than 24 h maintained homeothermy even when the pelt was artificially wetted. Oxygen consumption at thermoneutrality increased about 50% from hatching to 12 h of age. The specific thermal conductance of ducklings at different ages indicates that the youngest ducklings maintain homeothermy by having a cold periphery in addition to pelt insulation and increased VO2, while ducklings older than 12 h rely on pelt insulation and increased VO2 only.
