Baleen whales are large-bodied predators that, despite their critical role in marine ecosystems, our understanding of their physiological function remains limited. Few methods exist for studying whale health in the open ocean, but biologging tags remains a promising avenue for measuring animal physiology. This study examines the use of auscultation (i.e., a stethoscope) to non-invasively record physiological sounds, including heartbeats and respiratory patterns, from free-ranging baleen whales.