An observation of attempted infanticide and female-female cooperation in wild plains zebras (Equus quagga)

Male infanticide has been reported in a wide range of taxa as a strategy for redirecting maternal investment and increasing a male's chance of siring future offspring. Plains zebras (Equus quagga) possess many of the social organization and life history traits found to favour infanticide. However, most documented cases are from captive animals, while it has not been detected in studies of free-ranging populations. Here, we report an apparent infanticide attempt in which the historical associations of all participants were known. In addition, we report the first instance of non-kin female-female cooperative defence against male aggression in this species. We discuss why this behaviour may not have been observed by other longitudinal studies. We then explore how intraspecific and inter-individual variation may factor into its relative rarity, how the reproductive biology of plains zebras relates to this behaviour, and how female-female cooperation between non-kin can operate as an effective counterstrategy.