ECG and RR Interval Data from 12 Longest Dives in Steller Sea Lions

This dataset contains cardiac data collected from three Steller sea lions (<i>Eumetopias jubatus</i>) during trained, stationary breath-hold dives to depths of 3–4 m, conducted in a pool at the Vancouver Aquarium. Heart rate data were recorded using subcutaneous cardiac monitors (Medtronic Reveal XT) as part of a study investigating cardiovascular control and heart rate regulation during trained diving. The dataset includes CSV files containing extracted and manually corrected RR intervals with hand-coded annotations, as well as ECG traces exported as PDF files from the Medtronic Reveal XT system. These data support the analyses reported in the associated publication on heart rate dynamics and oscillatory patterns during dives in marine mammals. Both raw and processed cardiac data are provided to support transparency, reproducibility, and potential reanalysis of heart rate and dive response physiology.