Lactation costs in southern elephant seals at King George Island, South Shetland Islands.

CARLINI, A. R.; DANERI, G. A.; MARQUEZ, M. E. I.; BORNEMANN, H.; PANARELLO, H.0.; R CASAUX,; RAMDHOR, S.; PLOTZ, J.

POLAR BIOLOGY

Springer Verlag

Lugar: Berlin Heidelberg,Alemania; Año: 2004 vol. 27 p. 266 - 276

0722-4060

Abstract Labelled-water methodology was used to quantify energy costs and energy transferefficiency in 18 mother-pup pairs of southern elephant seals (Mirounga leonina) duringlactation. During the lactation period, mothers lost a mean mass of 227±47 kg. Mass lossincluded 22% of the protein, 60% of the fat, and 51% of the energy in the mother s bodyupon arrival. Total body-energy reserves at parturition explained 69% of the variation in thetotal lactation costs and 50% of the variation in the pup s body energy at weaning. Onaverage, pups retained 48% of the mass, 49% of protein, 53% of fat and 51% of energy lostby their mothers. Greater, fatter females showed a decrease in the efficiency of energy and fattransfer and, at the same time, an increase in the efficiency of protein transfer. This may bedue to an increased use of protein as metabolic fuel, as fat demands for milk productionincrease. There was no evidence that greater total lactation costs influence the ability ofmothers to produce a pup in the next breeding season.