In many mammalian species, both inter-individual and inter-group differences in vocalisations exist. Social learning may play a role in shaping such vocal individuality. The project investigates, mostly in the model species of the domestic pig, 3 main questions: 1. What constitutes vocal individuality in Sus scrofa and in related Suidae and Tayassuidae species? 2. How is vocal individuality co-determined by perceived vocalisations in early ontogeny? 3. Do pigs use vocal individuality to recognize individuals? The aims will be achieved (i) through recording of vocalisations in domestic piglets and sows, followed by state-of-art bioacoustic analysis, (ii) through cross-fostering of piglets at birth and quantifying later vocal similarity between biological and foster-siblings and in mother-daughter pairs, (iii) through testing whether mother sow recognise playbacks of their biological and foster piglets. The main result of the project will be a deeper insight into the mechanisms and functions of mammalian vocal individuality.