Paleontology owns thousands of Tyrannosaurus rex bones, dozens of skeletons, and exactly one thing it never had until this week: a recorded walk.<\/p>\n
In a study just published in the Journal of Vertebrate Paleontology, researchers from the Denver Museum of Nature & Science and Liverpool John Moores University describe the first trackway ever attributed to an adult T. rex<\/a> \u2014 four enormous three-toed footprints in sequence, two left and two right, pressed into what was Hell Creek mud about 66.5 million years ago, in the species\u2019 final act before the asteroid.<\/p>\n Bones are anatomy. A trackway is behavior \u2014 a preserved moment of an animal actually doing something. \u201cWith a trackway, we can actually follow an animal as it moved across the landscape,\u201d said Denver\u2019s senior curator Tyler Lyson. \u201cThat is incredibly rare for T. rex.\u201d<\/p>\n Reading the walk<\/p>\n The trackway, found in 2025 on U.S. Forest Service land near Marmarth, in North Dakota\u2019s fossil-rich southwest corner, runs about 23 feet, with each print roughly three feet long<\/a> and a stride \u2014 the gap between successive prints of the same foot \u2014 of approximately 13 feet.<\/p>\n Feed the stride and footprint size into the standard locomotion equations and out comes the headline number: the animal was moving at about 3.5 to 4.5 mph<\/a> \u2014 the pace of a brisk human walk. Seven tons of apex predator, out for a stroll. The team is careful to call the figure approximate, since the prints are heavily weathered \u2014 but the pace sits comfortably alongside other large theropod trackways and the biomechanical consensus that a walking T. rex preferred exactly this kind of unhurried gait.<\/p>\n The attribution rests on elimination. Tyrannosaur trackways found before \u2014 in Canada, in Wyoming \u2014 were left by smaller animals: juveniles, or smaller related species. These prints\u2019 sheer size, the narrow angle between the toe impressions, and the surrounding rock\u2019s abundance of adult T. rex bones leave no other known animal in the formation<\/a> matching the feet. Isolated single prints had been credited to adult rex before; a walking sequence \u2014 the thing that yields a stride, and therefore a speed \u2014 never.<\/p>\n The expert who never saw the tracks<\/p>\n The project\u2019s methods are as modern as its subject is ancient. The prints survive in an unusual medium \u2014 hardened, calcium-carbonate-cemented sandstone casts, natural sculptures of the original squelch \u2014 and the field team documented every print with high-resolution 3D surface scanning.<\/p>\n Which enabled the study\u2019s charming structural joke: lead author Peter Falkingham, one of the world\u2019s foremost dinosaur-track experts, analyzed the trackway without ever seeing it in person<\/a> \u2014 colleagues scanned the stones in the North Dakota badlands and sent him the models in Liverpool. The find itself, by the accounts circulating with the study, was first spotted not by a professional at all but by a high-school teacher working with the museum\u2019s field program \u2014 hikers and amateurs being, as track specialists have long noted, the discipline\u2019s best discovery engine.<\/p>\n Three of the four prints are due to be airlifted out by helicopter this fall<\/a> and installed at the Denver Museum.<\/p>\n Why a slow walk is big news<\/p>\n There is a mild comedy in the fact that the most fearsome animal ever to walk North America makes headlines for ambling \u2014 but the pedestrian pace is precisely the scientific payload.<\/p>\n How T. rex moved has been fought over for decades: the Jurassic Park jeep-chaser versus the biomechanical models showing that a running rex would have needed impossible quantities of leg muscle, with modern estimates converging on a fast-walking animal whose long legs made walking efficient rather than swift. Those conclusions, though, were built from bones, models and other species\u2019 tracks. This is the first time the actual animal has weighed in \u2014 an adult rex, caught mid-commute, moving at exactly the relaxed pace the equations predicted. One data point, and an unhurried one, but from the only witness that was there.<\/p>\n And that is the real gift of the Marmarth stones. Every skeleton is a death; a trackway is twenty-three feet of a Tuesday. Sixty-six and a half million years ago, in the last few hundred millennia of its species\u2019 existence, a full-grown Tyrannosaurus rex walked across a mudflat at the speed of a human late for lunch, going about business no one will ever know \u2014 and the mud kept the receipt.<\/p>\n About this article<\/p>\n This article is for general information and reflection. It is not professional advice. 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See our editorial standards<\/a> and masthead<\/a>.\n\t\t\t<\/p>\n","protected":false},"excerpt":{"rendered":"Paleontology owns thousands of Tyrannosaurus rex bones, dozens of skeletons, and exactly one thing it never had until…\n","protected":false},"author":2,"featured_media":845196,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32],"tags":[79],"class_list":["post-845195","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/845195","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=845195"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/845195\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/845196"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=845195"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=845195"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=845195"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}