Dinosaurs dragged their tails on the ground

Biomechanical and paleontological evidence shows most non-avian dinosaurs held their tails elevated above the ground, held relatively rigid by overlapping vertebrae and tendons. Trackway evidence lacks tail drag marks despite excellent fossil preservation in many sites. CT scans of theropod vertebrae reveal zygapophysis architecture that would have made tail dragging biomechanically inefficient. The tail served multiple functions: balance during running, sexual display, thermoregulation, and possibly communication. This elevated posture was particularly important for bipedal dinosaurs during rapid locomotion.