{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T03:11:16Z","timestamp":1777864276472,"version":"3.51.4"},"reference-count":60,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T00:00:00Z","timestamp":1777507200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:p>\n                    A seal\u2019s heart rate is affected by their physiological adaptation to aquatic and terrestrial environments. At-sea, heart rate during dive bouts cycles between bradycardia during dives and tachycardia for oxygen replenishment on the sea-surface. While onshore, heart rate reflects apnoea and eupnoea. Intriguingly, complete sea-and-onshore heart rate traces and any relationship between sea and subsequent onshore heart rate, including any immediate or delayed physiological adaptation, remain unexamined. In this study, sea-and-onshore heart rate traces from female Cape fur seals (\n                    <jats:italic>Arctocephalus pusillus pusillus<\/jats:italic>\n                    ; CFS,\n                    <jats:italic>N<\/jats:italic>\n                    = 4) and Australian fur seals (\n                    <jats:italic>A. p. doriferus<\/jats:italic>\n                    ; AUFS,\n                    <jats:italic>N<\/jats:italic>\n                    = 8) revealed expected at-sea cycles of bradycardia (mean minimum beats\u00b7min\n                    <jats:sup>-1<\/jats:sup>\n                    , CFS: 14.8 \u00b1 1.3 SE; AUFS: 5.7 \u00b1 1.6) and tachycardia (mean maximum beats\u00b7min\n                    <jats:sup>-1<\/jats:sup>\n                    , CFS: 161.1 \u00b1 1.5; AUFS:163.8 \u00b1 2.6), with interspaced periods where heart rate stabilized as the seal swam at the sea surface. Following haul-out, heart rate traces revealed peaks approximately 20 to 40 beats\u00b7min\n                    <jats:sup>-<\/jats:sup>\n                    \u00b9 above the apparent minimum, reaching a maximum 6 to 8 hours following the seal\u2019s return to land. Potentially, this onshore heart rate trace reflects a physiological response attributable to delayed compensation for at-sea debt, a scenario explored with multiple linear analyses of area under the heart rate curve, the results of which were all significant (\n                    <jats:italic>p<\/jats:italic>\n                    &amp;lt; 0.05) but varied in strength (\n                    <jats:italic>\n                      R\n                      <jats:sup>2<\/jats:sup>\n                    <\/jats:italic>\n                    range from 0.61 to 0.86). These findings underscore the complex interplay of heart rate across aquatic and terrestrial environments, highlighting the benefits of examining holistic physiological traces, and potentially revealing evidence for delayed metabolic processing.\n                  <\/jats:p>","DOI":"10.3389\/fphys.2026.1755942","type":"journal-article","created":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T05:39:18Z","timestamp":1777527558000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Aquatic and terrestrial heart rates in fur seals: evidence for delayed metabolic processing"],"prefix":"10.3389","volume":"17","author":[{"given":"Melissa J.","family":"Walker","sequence":"first","affiliation":[{"name":"School of Life and Environmental Sciences, Deakin University","place":["Burwood, VIC, Australia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel P.","family":"Costa","sequence":"additional","affiliation":[{"name":"Scripps Institution of Oceanography, University of California, San Diego","place":["San Diego, CA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stephen P.","family":"Kirkman","sequence":"additional","affiliation":[{"name":"Department of Forestry, Fisheries and the Environment: Oceans and Coasts","place":["Cape Town, South Africa"]},{"name":"Institute for Coastal and Marine Research, Nelson Mandela University","place":["Gqeberha, South Africa"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrew J.","family":"Hoskins","sequence":"additional","affiliation":[{"name":"North Australian Indigenous Land and Sea Management Alliance","place":["Brinkin, NT, Australia"]},{"name":"School of the Environment, University of Queensland","place":["Brisbane, QLD, Australia"]},{"name":"James Cook University","place":["Townsville, QLD, Australia"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"W. 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