Maternal effects on offspring social status in spotted hyenas

Social status is an important phenotypic trait that determines fitness-relevant parameters. In many mammalian societies, offspring acquire a social position at adulthood similar to that held by their mother ("rank inheritance") and thus obtain fitness benefits associated with this status. Mothers may influence the rank of their offspring at adulthood in at least three distinct ways. Firstly, the direct genetic inheritance of maternal traits that influence resource holding potential might predispose offspring to obtain a rank similar to that held by their mother. Secondly, the prenatal maternal environment might influence offspring rank if fetal exposure to maternal androgens is related to maternal status and affects offspring competitiveness. Thirdly, maternal behavioral support, a component of the postnatal maternal environment, may help offspring dominate individuals subordinate to their mother, thereby assisting offspring to acquire a rank similar to that of their mother. Here, we simultaneously test predictions derived from these three potential maternal effects on offspring rank acquisition at adulthood, using cases of offspring adoption in the spotted hyena Crocuta crocuta. We demonstrate that the rank of adopted offspring at adulthood was similar to that of their surrogate mother and that the competitive ability of offspring at adulthood was best explained by postnatal maternal behavioral support. Copyright 2009, Oxford University Press.