Change in the foraging strategy of female South American sea lions (Carnivora: Pinnipedia) after parturition


  • Massimiliano Drago Department of Animal Biology and Biodiversity Research Institute (IRBio), University of Barcelona
  • Luís Cardona Department of Animal Biology and Biodiversity Research Institute (IRBio), University of Barcelona
  • Enrique A. Crespo Laboratory of Marine Mammals, Centro Nacional Patagonico (CENPAT-CONICET) - National University of Patagonia
  • Néstor García Laboratory of Marine Mammals, Centro Nacional Patagonico (CENPAT-CONICET)
  • Santiago Ameghino National University of Patagonia
  • Alex Aguilar Department of Animal Biology and Biodiversity Research Institute (IRBio), University of Barcelona



South American sea lion, diet, feeding strategy, suckling pup, lactating females, Otaria flavescens, stable isotopes, Bayesian mixing models


This study tests the hypothesis that female South American sea lions shift from off-shore, pelagic prey to coastal, benthic prey after parturition in order to reduce the foraging trip duration and hence the time pups remain unattended on the beach during early lactation. The δ13C and δ15N values of the serum and blood cells of 26 South American sea lion suckling pups from northern Patagonia were used to track the dietary changes of their mothers from late pregnancy to early lactation, after correction for differential isotopic fractionation between tissues. Primary producers and potential prey species were also analysed to establish a baseline for interpreting the stable isotope concentration of serum and blood cells. Isotopic ratios revealed a generalized increase in the consumption of coastal-benthic prey after parturition. Such a generalized post-partum shift will allow females to spend more time on land and look after their pups. The effects of this foraging strategy on the nutritional quality of the female’s diet are discussed.


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How to Cite

Drago M, Cardona L, Crespo EA, García N, Ameghino S, Aguilar A. Change in the foraging strategy of female South American sea lions (Carnivora: Pinnipedia) after parturition. Sci. mar. [Internet]. 2010Sep.30 [cited 2024Feb.21];74(3):589-98. Available from:




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