True paternal care in a multi-male primate society

Although male parental care is rare among mammals1, adult males of many cercopithecine primate species provide care for infants and juveniles. This care is often in the form of grooming, carrying, support in agonistic interactions, and protection against infanticide2,3. For these behaviours to be interpreted as true parental care, males must selectively direct care towards their own offspring and this care must result in fitness benefits4. With the exception of males defending probable offspring from infanticide5, male primates living in multi-male, multi-female social groups have not been shown to selectively direct care towards their own offspring6,7. We determined paternity for 75 juveniles in a population of wild savannah baboons (Papio cynocephalus) and collected data on interventions in agonistic disputes by adult males on behalf of juveniles as a form of male care. Here we show that adult males differentiate their offspring from unrelated juveniles and selectively support their offspring in agonistic disputes. As support in agonistic disputes is likely to contribute to rank acquisition and protect juveniles from injury and stress2,3,5, this can be considered true parental care.