Overview
- A volunteer high school teacher discovered a sequence of large three‑toed prints on U.S. Forest Service land near Marmarth, North Dakota in 2025, which prompted field teams to document the site with high‑resolution 3D scans and digital models.
- The described trackway is about seven metres long and preserves four tridactyl casts, each roughly one metre in length with an average stride near four metres that yields an estimated walking speed of about 1.5–2 m/s.
- Authors of the Journal of Vertebrate Paleontology paper conclude an adult Tyrannosaurus rex is the most likely trackmaker based on print size, toe proportions, site locality, and nearby T. rex body fossils, but they emphasize this attribution is probabilistic because the casts are heavily weathered.
- The prints survived as sandstone concretions cemented with calcium carbonate, three of the four casts have been wrapped for helicopter removal with U.S. Forest Service permission, and the combination of physical casts plus 3D data will let researchers test gait and foot‑anatomy hypotheses off‑site.
- Researchers say the find is scientifically valuable because trackways record an animal in motion and could reveal gait details or skin impressions, but further excavation is unlikely due to local overburden and erosion so study will rely on the recovered casts and digital models.