Individual contributions to babysitting in a cooperative mongoose, Suricata suricatta

Evolutionary explanations of cooperative breeding based on kin selection ha ve predicted that the individual contributions made by different helpers to rearing young should be correlated with their degree of kinship to the lit ter or brood they are raising. In the cooperative mongoose or meerkat, Suri cata suricatta, helpers babysit pups at the natal burrow for the first mont h of pup life and frequent babysitters suffer substantial weight losses ove r the period of babysitting. Large differences in contributions exist betwe en helpers, which are correlated with their age, sex and weight but not wit h their kinship to the young they are raising. Provision of food to some gr oup members raises the contributions of individuals to babysitting. We disc uss the implications of these results for evolutionary explanations of coop erative behaviour.