Ontogeny of vocal rhythms in harbor seal pups: An exploratory study

Puppyhood is a very active social and vocal period in a harbour seal’s life Phoca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythms in harbour seals is critical to a cross-species hypothesis in evolutionary neuroscience that links vocal learning, rhythm perception, and synchronisation. The current study utilised analytical techniques that may best capture rhythmic structure in pup vocalisations with the goal of examining whether (i) harbour seal pups show rhythmic structure in their calls and (ii) rhythms evolve over time. Calls of three wild-born seal pups were recorded daily over the course of 1–3 weeks; three temporal features were analysed using three complementary techniques. We identified temporal and rhythmic structure in pup calls across different time windows. The calls of harbour seal pups exhibit some degree of temporal and rhythmic organisation, which evolves over puppyhood and resembles that of other species’ interactive communication. We suggest next steps for investigating call structure in harbour seal pups and propose comparative hypotheses to test in other pinniped species.