Ornithomimus

Ornithomimus is the defining genus of the ostrich dinosaurs, living in western North America during the final stages of the Cretaceous period. It was a bipedal cursorial animal of moderate size, roughly three and a half to four metres long, characterised by hollow bones, long limbs, and a toothless, horny beak. Landmark fossil discoveries from Alberta preserved impressions of filamentous plumage across the body as well as wing-like feather structures on the forelimbs of adult individuals, demonstrating that ornate plumage developed as these animals matured. With grasping hands and agile feet, Ornithomimus was well equipped to sprint away from apex predators like tyrannosaurs. Its diet was broad and opportunistic, likely consisting of foliage, fruits, insects, and eggs. Ornithomimus provides crucial insight into the transition and shared biology between non-avian theropod dinosaurs and modern ground-dwelling birds.

Spectacular Canadian fossils preserve direct evidence of feathers, including pennaceous wing-like structures in adults.

Where and when

Ornithomimus lived in the Late Cretaceous, from 76.5 to 66 million years ago (Campanian-Maastrichtian age). Its remains come from Canada and United States, in the Dinosaur Park Formation.

The numbers

Length 3.8 m (estimates run from 3.5 to 4 m). Mass about 150 kg. Hip height about 1.5 m. That is 2.2 human-lengths, or 0.34 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Ornithomimus with a bus Place on the timeline