A thirteen to fifteen-foot-long (4 to 4.6-meter) omnivorous theropod dinosaur from the Late Cretaceous Period that had large hips, a long tail, and strong hind limbs: "Ornithomimus has been discovered in several places in the western United States and Canada."

"Ornithomimids looked very much like modern ostriches (except for their long tails); and, although their heads were small, they had large brain areas which probably were dedicated to kinesthetic (movement) coordination, according to some paleontologists."