{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T15:59:42Z","timestamp":1792425582047,"version":"4.5.0"},"reference-count":37,"publisher":"National Academy of Sciences","issue":"52","license":[{"start":{"date-parts":[[2024,12,16]],"date-time":"2024-12-16T00:00:00Z","timestamp":1734307200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100009152","name":"Bertarelli Foundation","doi-asserted-by":"crossref","award":["projects 2017-4 820633"],"award-info":[{"award-number":["projects 2017-4 820633"]}],"id":[{"id":"10.13039\/100009152","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2024,12,24]]},"abstract":"<jats:p>\n                    Semiaquatic taxa, including humans, often swim at the air\u2013water interface where they waste energy generating surface waves. For fully marine animals however, theory predicts the most cost-efficient depth-use pattern for migrating, air-breathing species that do not feed in transit is to travel at around 2 to 3 times the depth of their body diameter, to minimize the vertical distance traveled while avoiding wave drag close to the surface. This has rarely been examined, however, due to depth measurement resolution issues at the surface. Here, we present evidence for the use of this strategy in the wild to the nearest centimeter and document the switch to shallow swimming during naturally occurring long-distance migrations. Using high-resolution depth-accelerometry and video data for little penguins (\n                    <jats:italic>Eudyptula minor<\/jats:italic>\n                    ) and loggerhead turtles (\n                    <jats:italic>Caretta caretta<\/jats:italic>\n                    ), satellite-relayed data for green turtles (\n                    <jats:italic>Chelonia mydas<\/jats:italic>\n                    ), and literature data for further sea turtle, penguin, and whale species, we show that near-surface swimming is likely used broadly across nonforaging diving animals to minimize the cost of transport.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2413768121","type":"journal-article","created":{"date-parts":[[2024,12,16]],"date-time":"2024-12-16T15:11:56Z","timestamp":1734361916000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":10,"title":["Optimization of swim depth across diverse taxa during horizontal travel"],"prefix":"10.1073","volume":"121","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5144-5008","authenticated-orcid":false,"given":"Kimberley L.","family":"Stokes","sequence":"first","affiliation":[{"name":"Department of Biosciences, Swansea University","place":["Swansea, Wales, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4693-7221","authenticated-orcid":false,"given":"Nicole","family":"Esteban","sequence":"additional","affiliation":[{"name":"Department of Biosciences, Swansea University","place":["Swansea, Wales, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paolo","family":"Casale","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Pisa","place":["Pisa, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6178-4211","authenticated-orcid":false,"given":"Andr\u00e9","family":"Chiaradia","sequence":"additional","affiliation":[{"name":"Conservation Department, Phillip Island Nature Parks","place":["Cowes, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yakup","family":"Kaska","sequence":"additional","affiliation":[{"name":"Department of Biology, Pamukkale University","place":["Denizli, T\u00fcrkiye"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8947-3634","authenticated-orcid":false,"given":"Akiko","family":"Kato","sequence":"additional","affiliation":[{"name":"Centre d\u2019\u00c9tudes Biologiques de Chiz\u00e9, UMR7372 CNRS-La Rochelle Universit\u00e9","place":["Villiers-en-Bois, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7081-3507","authenticated-orcid":false,"given":"Paolo","family":"Luschi","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Pisa","place":["Pisa, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yan","family":"Ropert-Coudert","sequence":"additional","affiliation":[{"name":"Centre d\u2019\u00c9tudes Biologiques de Chiz\u00e9, UMR7372 CNRS-La Rochelle Universit\u00e9","place":["Villiers-en-Bois, France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9401-913X","authenticated-orcid":false,"given":"Holly J.","family":"Stokes","sequence":"additional","affiliation":[{"name":"Department of Biosciences, Swansea University","place":["Swansea, Wales, United Kingdom"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3314-8189","authenticated-orcid":false,"given":"Graeme C.","family":"Hays","sequence":"additional","affiliation":[{"name":"Deakin Marine Research and Innovation Centre, School of Life and Environmental Sciences, Deakin University","place":["Geelong, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2024,12,16]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.288.5463.133"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1258732"},{"key":"e_1_3_4_3_2","volume-title":"Structure Form Movement","author":"Hertel H.","year":"1966","unstructured":"H. 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Nousek-McGregor, The Cost of Locomotion in North Atlantic Right Whales (Duke University, 2010)."},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1186\/s40317-016-0109-4"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-031-33990-5"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.202.22.3121"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jembe.2007.12.010"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1139\/f03-144"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1716137115"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.tree.2008.03.005"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1139\/z88-064"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2656.2008.01509.x"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.048207"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1098\/rstb.2007.2107"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1016\/B978-012415031-7\/50018-5"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.adf0566"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1242\/jeb.185603"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsif.2012.0477"},{"key":"e_1_3_4_30_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.zool.2009.12.001"},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1086\/680010"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.1114898"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.3389\/fspor.2022.894066"},{"key":"e_1_3_4_34_2","doi-asserted-by":"publisher","DOI":"10.1038\/35099670"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.aaf4374"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1038\/ncomms1350"},{"key":"e_1_3_4_37_2","doi-asserted-by":"crossref","unstructured":"K. L. Stokes Data from \u201cOptimization of swim depth across diverse taxa during horizontal travel.\u201d Dryad. https:\/\/doi.org\/10.5061\/dryad.rn8pk0pks. 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