Maternal social status and sibling rivalry shape milk transfer in spotted hyenas
Females of low social status often have limited access to food resources. As a result, their offspring are nursed infrequently and may experience long fasting periods that can seriously compromise their growth and survival. In particular when they have to share their milk intake with a littermate, milk shortage can be very detrimental. Yet researchers from the German Leibniz Institute for Zoo and Wildlife Research (IZW) and the German Max-Planck-Institute for Behavioral Physiology found that low-ranking spotted hyenas were able to compensate to some extent for their low nursing frequency. They do this by transferring more milk of superior nutritional quality to their offspring than high-ranking mothers during nursing bouts. The results also reveal that the socially dominant offspring in twin litters efficiently uses aggression against its subordinate littermate to skew milk transfer in its favour. The study has been published in the scientific journal Behavioural Ecology.