Intraspecific allometry of neonatal size in the antarctic fur seal (Arctocephalus galapagoensis)

• Published in: Behavioral Ecology and Sociobiology
• Main Authors: Costa, D. P., Trillmich, Fritz, Croxall, J. P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science + Business Media 1988
• Subjects: ddc:590; Antarctic; The Antarctic; Antarc*; Antarctic Fur Seal; Antarctic Fur Seals; Arctocephalus gazella
• Online Access: https://nbn-resolving.org/urn:nbn:de:0070-pub-17818843; https://pub.uni-bielefeld.de/record/1781884; https://pub.uni-bielefeld.de/download/1781884/2313563

Costa DP, Trillmich F, Croxall JP. Intraspecific allometry of neonatal size in the antarctic fur seal (Arctocephalus galapagoensis). Behavioral Ecology and Sociobiology . 1988;22(5):361-364. Intraspecific allometry of pup mass as a function of maternal mass was analysed in Antarctic fur seals (Arctocephalus gazella), a highly dimorphic species. The allometric exponent was 0.6, much lower than in interspecific comparisons. Slopes were the same for mother-son pairs as for mother-daughter pairs, but adjusted means were significantly higher for the former, indicating higher reproductive effort of mothers of sons. The correlation of maternal mass with pup mass explained 59% of the variance in female pup mas but only 18% of that in male pup mass. Females appeared to produce sons which were as big as possible. Relative pup mass decreased with increasing maternal mass indicating a lower reproductive effort of bigger and presumably older mothers, contrary to expectations from life history theory. Sex ratio of pups showed no relation to maternal mass.