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Identifying individuals' foraging strategies is critical to understanding the ecology of a species, and can provide the means to predict possible ecological responses to environmental change. Our study combines stable isotope analysis and satellite telemetry to study the variability in individual foraging strategies of adult female southern elephant seals ( Mirounga leonina). Our hypothesis is that female elephant seals from the Western Antarctica Peninsula (WAP) display individual specialization in their diets. We captured adult female elephant seals ( n = 56, 2005-2009) at Livingston Island (Antarctica), and instrumented them with SMRU-CTD satellite tags. We collected blood, fur, and vibrissae samples for δC and δN analyses. The mean values for all vibrissae were −21.0 ± 0.7‰ for δC, and 10.4 ± 0.8‰, for δN. The individual variability of δC (60%) was more important than the within-individual variability (40%) in explaining the total variance observed in our data. For δN, the results showed the opposite trend, with the within-individual variability (64%) contributing more to the total variance than the individual variability (36%), likely associated with the effect that the fasting periods have on δN values. Most individuals were specialists, as inferred from the low intra-individual variability of δC values with respect to the population variability, with half the individuals utilizing 31% or less of their available niche. We found eight different foraging strategies for these animals. Female elephant seals from the WAP are a diverse group of predators with individuals utilizing only a small portion of the total available niche, with the consequent potential to expand their foraging habits to exploit other resources or environments in the Southern Ocean. [ABSTRACT FROM AUTHOR]