Many species exhibit skewed sex ratios at birth. Here we investigate the relationships between environmental and maternal variables (as surrogates for maternal condition) and foetal sex in African buffalo Syncerus caffer and elephant Loxodonta africana of the Kruger National Park, South Africa. Using logistic regression no significant effect was found of year, maternal lactational status, maternal age, rainfall or density on foetal sex ratio. Using a subset of our data, it was also concluded that maternal body condition did not affect foetal sex ratio in buffalo. Our analyses failed to support hypotheses predicting that mothers will skew the sex ratios of their offspring in relation to their body condition. In this study, buffalo and elephant produced offspring with a sex ratio close to parity. Our results are discussed in light of the implications for testing such hypotheses in analyses of population level.
