Dear Colleagues, We're happy to share our new open-access Perspective paper in BMC Biology. https://link.springer.com/article/10.1186/s12915-026-02675-8 This was an interdisciplinary effort bringing together marine mammal physiologists, social ecologists, cognitive neuroscientists, evolutionary modelers, and experts in biorhythms. We argue that marine mammals are productive models for examining the evolution of vocal and social rhythms. Our approach integrates current understanding of the contribution of peripheral physiological and central nervous system mechanisms for creating and maintaining rhythmic vocalizations, and links these with field data examining social coordination across species. Citation: Cook, P.F., Flem, S., Madsen, P.T., Ravignani, A., Gremore, P., Hood, C., Jadoul, Y., Papageorgiou, D., Pedersen, M., Raimondi, T., Rouse, A., Sorensen, P., Videsen, S. & King, S.L. Marine mammals as models for charting the evolution of social vocal rhythm. *BMC Biol* (2026). https://doi.org/10.1186/s12915-026-02675-8 Abstract In this Perspective, we suggest combining physiological, neurobiological, behavioural, and social data from multiple marine mammal species to create evolutionary models of the emergence of social vocal coordination. Marine mammal sound production mechanisms have evolved to manage vocalizing and breathing in an aquatic environment, potentially releasing functional constraints on the control of vocal timing. Intervals in rhythmic cetacean vocalizations cover a remarkable temporal range, from less than a millisecond in porpoise burst pulses to 10 s in sperm whale slow clicks. Many cetaceans demonstrate temporally coordinated social behaviour, while pinnipeds express high variability in vocal plasticity and social behaviour. The systematic variability of vocal production mechanisms, vocal rhythms, and sociality can be compared phylogenetically to generate models for the evolution of social rhythm in the vocal domain. All the best, Peter (on behalf of co-authors) Peter F. Cook, Ph.D Associate Professor of Psychology and Marine Mammal Science Master's in Marine Mammal Science New College of Florida Research Associate Institute for Marine Sciences University of California Santa Cruz *@pfcooklab.bsky.social*