Abstract

Previous studies monitoring free-ranging capybaras with GPS collars showed no evidence of capybara dispersion or the formation of new groups. These phenomena may have gone unnoticed due to the low number of collared capybaras in previous studies. Aiming to fill this lacuna, this study monitored the group dynamics of capybaras in a human-modified landscape in Pirassununga municipality, state of São Paulo, southeastern Brazil. To this aim, we documented group formation, number of individuals, and dispersion events of capybara groups from 2015 to 2020. We evaluated the presence of established groups and formation of new groups throughout the study period, when we monitored 12 adult female capybaras with GPS-collars and regularly counted the number of individuals per group. We found that an initial group of 33-45 capybaras split itself into two groups from 2016 to 2017, and then into three groups from 2019 to 2020, each one with at least 30 individuals. This is the first study reporting group dynamics in capybaras with the use of GPS-collars. Long-term studies are needed to assess the factors that are driving the formation and division of groups, and motivating dispersion events.