Using the fossil and fossilized footprints of a 300-million-year-old animal, scientists from EPFL and Humboldt-Universität zu Berlin have identified the most likely gaits of extinct animals and designed a robot that can recreate an extinct animal's walk. This study can help researchers better understand how vertebrate locomotion evolved over time. How did vertebrates walk 300 million years ago? Could they already stand upright on their legs? Did they move in a balanced, energy-efficient way?

Nearly 300 million years ago, a curious creature called Orobates pabsti walked the land. Animals had just begun pulling themselves out of the water and exploring the big, dry world, and here was the plant-eating tetrapod Orobates, making its way on four legs. Paleontologists know it did so because one particularly well-preserved fossil has, well, four legs. And luckily enough, scientists also discovered fossilized footprints, or trackways, to match. The assumption has been that Orobates--a cousin of the amniote lineage, which today includes mammals and reptiles--and other early tetrapods hadn't yet evolved an "advanced" gait, instead dragging themselves along more like salamanders.