Inferring kinship from behaviour: Maternity determinations in yellow baboons

Kinship is commonly inferred from behaviour in primate field studies, but the validity of such inferences has not yet been documented. A comparison of the relationships of six three-year-old yellow baboon (Papio cynocephalus) females with 14 adult females showed that when a juvenile's mother was living she could easily be identified from behavioural data. The most useful behaviour in this context was Presenting For Grooming. When the mother was not living, however, the juvenile compensated by forming a strong relationship with a less closely related or unrelated adult female. If compensation also occurs in other populations and other species, past attempts to infer kinship from behaviour have probably included a few cases in which a female was incorrectly identified as a juvenile's mother. Multivariate statistical techniques revealed differences between mother-daughter relationships and strong relationships based on compensation among other individuals. These differences involved comparisons of the frequencies of certain behaviours (frequency of Grooming by adult versus frequency of Grooming by juvenile, frequency of Grooming versus frequency of aggression) as well as the magnitudes of frequencies (amount of Grooming, number of Interventions).