{"paper_id":"246a2087-196f-4e0e-91c4-cf597df51a96","body_text":"This is a Preprint and has not been peer reviewed. This is version 6 of this Preprint.\nYou must log in to post a comment.\nThere are no comments or no comments have been made public for this article.\nThis is a Preprint and has not been peer reviewed. This is version 6 of this Preprint.\nAdd a Comment\nYou must log in to post a comment.\nComments\nThere are no comments or no comments have been made public for this article.\nMonitoring stress and emotional states in dolphins is an important step toward improving animal welfare in managed care. Established physiological approaches, such as measuring cortisol from blood or fecal samples, have provided valuable information for stress assessment. Suction-based devices have also enabled cardiac monitoring, contributing to our understanding of diving physiology and circulatory control. Each of these methods offers unique strengths, but they may not always be suited for real-time or continuous monitoring during routine conditions. In this study, we propose a framework in which heart rate variability (HRV) serves as a non-invasive indicator of autonomic activity, stress, and emotional states. As an initial step, we tested the feasibility of attaching a commercially available belt-type heart rate monitor to dolphins. The device was fitted safely and generally tolerated, although subtle behavioral resistance was observed in some cases. In principle, this HRV-based framework is not limited to the belt-type device tested here and could be adapted to other attachment methods, provided stable cardiac signals are obtained. Continuous cardiac signal acquisition and HRV analysis are ongoing, but these preliminary results represent a first step toward introducing HRV-based welfare assessment in cetaceans. Importantly, the feasibility of this approach under routine husbandry conditions supports the development of practical, physiology-based welfare indicators that can be implemented on site by animal care staff. This framework has the potential to extend beyond dolphins to other marine mammals such as pinnipeds and sirenians, thereby contributing to the establishment of practical, non-invasive welfare assessment standards for zoos and aquaria.\nhttps://doi.org/10.32942/X20H15\nLife Sciences, Social and Behavioral Sciences\nDolphins, heart rate variability, HRV, animal welfare, stress assessment, marine mammals, Autonomic Nervous System, non-invasive monitoring, zoo and aquarium\nPublished: 2025-09-24 16:57\nLast Updated: 2026-03-31 14:47\n- Version 5 - 2026-02-09\n- Version 4 - 2025-10-21\n- Version 3 - 2025-10-21\n- Version 2 - 2025-09-24\n- Version 1 - 2025-09-24\nCC BY Attribution 4.0 International\nConflict of interest statement:\nNone\nData and Code Availability Statement:\nNo datasets or code are associated with this preprint.\nLanguage:\nEnglish","source_license":"CC-BY-4.0","license_restricted":false}