An integrative, peer-reviewed and open-source cooperative-breeding database (Co-BreeD).

Large-scale, cross-species comparative analyses on cooperative breeding-where individuals care for the offspring of other group members-are important for understanding sociality and cooperation. However, the datasets that facilitate these analyses are often limited in precision. To advance comparative research on cooperative breeding, we hereby introduce the Cooperative-Breeding Database (Co-BreeD) for birds and mammals. We describe key features of Co-BreeD's structure: (i) integration of complementary datasets, each presenting a biological parameter relevant to cooperative-breeding research; (ii) sample-based (i.e. multiple samples per species linked to an exact sampling location and period); and (iii) open-source. Respectively, these features enable: (a) comprehensive identification of cooperative-breeding species according to the user's chosen definition, (b) linking intra- and inter-specific variation in traits with fine-scale environmental parameters and (c) enabling the research community to correct and expand this database. We present the initial Co-BreeD dataset, which estimates the prevalence of breeding events involving potential alloparents in 460 populations of 324 species, including 6 human populations (No. total = 43,247 breeding events). We conclude by demonstrating: (i) how Co-BreeD can improve comparative research (e.g. by enabling the study of cooperative breeding as a continuous rather than a binary trait); and (ii) that cooperative breeding is probably more prevalent than previously estimated in birds and mammals.