Classification of meerkat contact calls by age and relevance for group cohesion during foraging

Like many group-living mammals, meerkats (Suricatta suricatta) rely on acoustic signals to coordinate activities and maintain group cohesion. While foraging, meerkats produce medium-frequency pulsated vocalizations named close calls, which help maintain contact between individuals. Previous studies suggested that close calls may convey individual information. This study examined age-related variation in close calls of male and female meerkats to provide a basis for exploring inter-individual differences and potential vocal recognition. Close calls of wild but habituated meerkats were recorded in a standardized behavioral context between 2014 and 2024 in the Kuruman River Reserve (South Africa). Temporal and spectral features were measured on 2,754 good-quality close calls from 159 different individuals across six age classes: 3, 6, 12, 18, 24, or 30 months. Using a supervised classification algorithm (Random Forest), we found that close calls emitted by young individuals (3–6 months old) differ significantly from those of adults, which remain stable in acoustic structure after 12 months. We discuss the potential origins of this variation (vocal ontogeny) and its implications on the modulation of social interactions (food competition) and the maintenance of group cohesion during foraging in the highly social meerkat species.