Ornithomimus was discovered in the Denver Formation of Colorado in 1890. This theropod roamed North America during the Late Cretaceous Period more than 66 million years ago. The Ornithomimus dinosaur had long legs, long necks, and bird-like arms.
Ornithomimus was covered in feathers and had beaked skulls without any teeth. This dinosaur resembled the modern-day ostrich. Because they didn’t have any teeth, paleontologists believe Ornithomimus ate an omnivorous diet but favored plants. Their long limbs and hollow bones made them fast runners. Ornithomimus’ hands were curved, resembling a sloth’s claws, which made them ideal for hooking onto branches while they fed.