The data in this dataset are derived from long-term, individual-based field studies of wild populations of four mammal species: banded mongoose (Mungos mungo), spotted hyena (Crocuta crocuta), chimpanzee (Pan troglodytes), and yellow baboon (Papio cynocephalus). The data contain demographic records (births, deaths, group membership), behavioural observations, and genetic parentage data to construct pedigrees and estimate local relatedness among group members. Across all four species, the data are structured as longitudinal, individual-level records ("individual-years"), and include; individual identity, sex, and age (z scored), group size by year and estimated local relatedness from pedigree. Banded mongooses were studied in Queen Elizabeth National Park, Uganda, as part of the Banded Mongoose Research Project. The dataset covers the period 2000-2019 and includes a population of approximately 197-326 individuals living in 6-13 social groups per year. Individuals are uniquely marked and observed frequently (every 1-4 days), resulting in highly resolved life-history data including dates of birth and death, group membership, and reproductive events. Parentage is assigned using genetic data for the majority of individuals. Spotted hyena data were collected from eight clans in the Ngorongoro Crater, Tanzania, as part of the Ngorongoro Hyena Project (since 1996). Individuals are identified by unique spot patterns and monitored through near-daily observations. The dataset includes demographic and life-history information (age estimates, dispersal, survival) alongside genetic parentage assignments derived from microsatellite data. Clan sizes vary over time (mean c. 24-43 individuals). Chimpanzee data derive from long-term studies of the North and South communities in Taï National Park, Côte d'Ivoire, conducted by the Taï Chimpanzee Project. Continuous behavioural and demographic observation has been conducted since 1985 (North) and 1997 (South). Group membership, births, deaths, and dispersal are inferred from direct observation, with maternity assigned behaviourally and confirmed genetically, and paternity inferred genetically. Group sizes range from approximately 10-42 adults. Yellow baboon data come from the Amboseli Baboon Research Project in Amboseli National Park, Kenya, with data used here spanning from 1988 onwards. The study includes multiple social groups (mean ~5 per year) with group sizes ranging from 14 to 130 individuals. Individuals are monitored on a near-daily basis, with detailed records of births, deaths, dispersal, and group composition. Parentage is determined using long-term field observations and genetic analyses (microsatellite data). Full details about this dataset can be found at https://doi.org/10.5285/034802f9-c8bd-4fcf-aee5-97ea2478cf99