Vocal Signatures in Rams: Exploring Individual Distinctiveness Across Different Contexts

Individual vocal recognition is essential for social cohesion and survival among conspecifics. In sheep, it facilitates postnatal identification and strengthens the mother–offspring bond. Although vocal individuality has been well-documented in lambs and ewes, little is known about whether rams—typically reared separately in farming systems—exhibit acoustic distinctiveness. This study investigated whether rams express vocal individuality across different emotional contexts and whether their calls convey contextual information. Adult rams’ vocalizations were recorded across five emotionally distinct contexts: physical and visual isolation (morning and evening), auditory exposure to ewes’ bells without visual contact, feed anticipation, and feed denial. Implementing discriminant function analyses and linear mixed models, we assessed individual distinctiveness and contextual variation in acoustic parameters. Rams exhibited vocal individuality ranging from 59% to 80%, with higher distinctiveness in negative contexts compared to positive ones. Vocal distinctiveness persisted across contexts, albeit to a lesser degree, suggesting some degree of acoustic stability. Calls were classified above chance by context, suggesting rams use vocalizations to convey affective states. Formant dispersion and amplitude variation were the most informative raw acoustic parameters under negative from positive contexts. The findings indicate that rams exhibit context-dependent vocal individuality, potentially conveying affective states through vocalizations.