Infant carrying by a wild chimpanzee father at Bulindi, Uganda.

Although infanticide by wild adult male chimpanzees has been reported from multiple sites, affiliative infant carrying by males is rare. We observed infant carrying by an alpha male chimpanzee at Bulindi (Uganda) on two consecutive mornings and collected faecal samples from the newborn infant female, her mother and all candidate fathers to determine whether the alpha male was the infant's father using a likelihood-based method of paternity assignment. In contrast to previous observations of male care of orphans, in this case the mother was present during observations. Further, unlike reports of male aggression towards infants, the infant was reunited with her mother on the third morning, and survived. Neither mother nor infant presented visible injuries. The alpha male never directed aggression towards the infant. Rather, he displayed attentive behaviours, for example by holding the infant to his chest, supporting her while moving, grooming her, and 'cuddling' and 'rocking' her. Paternity results revealed with a high degree of certainty that the alpha male was the infant's father. There are several alternative explanations for the male's behaviour, but this unusual case also highlights the need for further studies to determine under what circumstances adult male chimpanzees can recognise their own offspring.