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Inside a computer-built trail behind the dolphin, the strongest evidence appeared in the moving water near the tail.<\/p>\n
By tracing those rings, Yutaro Motoori, who studies moving water at The University of Osaka (UOsaka<\/a>) in Japan, showed that the largest swirls drove the useful push.<\/p>\n The smaller swirls still filled the trail, but they mostly came from larger rings stretching and breaking the water.<\/p>\n That separation sharpens the next question: how a tail kick turns those large rings into forward speed.<\/p>\n Rings push dolphin forward<\/p>\n Engineers call each ring a vortex<\/a>, a rotating pocket of fluid that carries motion through water.<\/p>\n When the dolphin\u2019s tail moves down, the ring forms along the tail edge and then peels away.<\/p>\n As that ring leaves, it pushes water backward, and the dolphin gains forward momentum from the exchange.<\/p>\n In the simulations, the backward jet carried the main share of thrust, the forward force that moves a swimmer.<\/p>\n Turbulence sorts itself<\/p>\n Fast swimming also creates turbulence<\/a>, an unstable flow that breaks into changing swirls of many sizes.<\/p>\n Large rings stretched nearby water, and that stretching created smaller swirls through an energy cascade, a handoff of motion from large to small.<\/p>\n Many tiny eddies<\/a>, small swirling currents, appeared in the wake, yet their number did not make them the main engine.<\/p>\n For dolphin speed, size mattered more than clutter because the biggest rings carried the strongest backward momentum.<\/p>\n Computer model shows flow<\/p>\n To test the flow without disturbing a living animal, the team used a direct numerical simulation, a computer model that solves fluid motion step by step.<\/p>\n A related visualization effort<\/a> handled about 1.9 billion grid points, digital locations where the program tracked water movement, to show layered swirls.<\/p>\n \u201cUsing a supercomputer, we can simulate and decompose the flow to determine which components play dominant roles,\u201d said Motoori.<\/p>\n On Fugaku, a supercomputer in Kobe, Japan, that detail exposed wake patterns that real-world filming would struggle to capture.<\/p>\n Large vortex rings won because they formed at the moving tail edge, where muscle-driven motion met the water directly.<\/p>\n During the downstroke<\/a>, the downward part of the kick, the tail swept water into a ring that detached and carried momentum backward.<\/p>\n After detachment, the dolphin moved forward because the water had received an opposite push from the tail.<\/p>\n That cause-and-effect chain explains why the largest structures, not the smallest ones, dominated propulsion across tested speeds.<\/p>\n Small swirls still matter<\/p>\n Tiny vortices did not become irrelevant, because they showed how a large push becomes ordinary turbulent motion.<\/p>\n As bigger rings stretched the water, small swirls spun off and filled the trail behind the dolphin.<\/p>\n Numerous small structures helped researchers check the flow\u2019s realism, but they added little to forward force.<\/p>\n For designers, ignoring them entirely would lose detail, while treating them as the main source of speed would miss the point.<\/p>\n Robots copy dolphin motion<\/p>\n Underwater engineers care about this result because many machines still waste power pushing water in messy patterns.<\/p>\n Robots that copy animal swimming, called biomimetic robots<\/a>, already use flexible bodies, tails, fins, and control systems.<\/p>\n A dolphin-style lesson points designers toward building strong, well-timed rings instead of merely adding more tail motion.<\/p>\n Such designs could help inspection vehicles, ocean sensors, and search tools travel farther on the same stored energy.<\/p>\n Limits of the model<\/p>\n Simulated water still has limits, even when the numbers are large and the physics is carefully solved.<\/p>\n The modeled body came from measurements of a Pacific white-sided dolphin<\/a>, a real dolphin species used for the body shape.<\/p>\n Its swimming motion was set in advance, which means nerves, decisions, fatigue, and live muscle feedback stayed outside the calculation.<\/p>\n Those boundaries do not erase the result, but they keep the finding focused on tail-driven motion rather than dolphin behavior.<\/p>\n Same idea may apply to other animals<\/p>\n Beyond dolphins, the same hierarchy may help explain other animals that move through water or air.<\/p>\n Bird wings, fish tails, and insect wings all leave organized swirls that can carry useful momentum.<\/p>\n Seeing those structures by size helps researchers separate the force-making flow from the smaller leftovers.<\/p>\n That view could improve turbulence control, reducing unstable flow to cut unwanted drag, noise, and wasted energy.<\/p>\n What the finding gives<\/p>\n The dolphin\u2019s wake now has a clear sequence: tail motion, large vortex rings, backward water<\/a>, forward thrust.<\/p>\n Future tests can compare simulations with animal-safe measurements and robot trials, while keeping the main lesson clear and usable.<\/p>\n The study is published in Physical Review Fluids<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.\u00a0<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"A new study has found that large rings of swirling water provide most of the push behind dolphins\u2019…\n","protected":false},"author":2,"featured_media":645129,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-645128","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/645128","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=645128"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/645128\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/645129"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=645128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=645128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=645128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"The](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/05\/dolphins-fast-swim_vortices_ocean-eddies_graphic_1s.webp.webp\")
<\/a>The smallest-scale vortices identified help explain the fast swimming of dolphins by polygonal isosurfaces around their bodies. Credit: European Journal of Mechanics \u2013 B\/Fluids. Click image to enlarge.Bigger rings give thrust<\/p>\n