Dromiceiomimus

Dromiceiomimus was a slender ostrich-like theropod that roamed the river plains and open woodlands of prehistoric Alberta during the Late Cretaceous period. Discovered in formations such as the Horseshoe Canyon Formation, it is celebrated for its remarkably long lower legs and oversized eye sockets. These anatomical adaptations strongly suggest that it was an exceptionally rapid runner and may have had keen vision suited to feeding during twilight hours. Like related ornithomimids, it lacked teeth and instead possessed a delicate, keratinous beak. Its diet was likely omnivorous, taking advantage of a wide selection of shoots, seeds, insects, and small vertebrates. Although several researchers have considered it synonymous with Ornithomimus, ongoing studies keep the distinct nature of its skeletal proportions in active scientific discussion.

It possessed unusually large eye sockets and slender leg proportions compared with other North American ornithomimids.

Where and when

Dromiceiomimus lived in the Late Cretaceous, from 73.5 to 68.5 million years ago (Campanian-Maastrichtian age). Its remains come from Canada, in the Horseshoe Canyon Formation.

The numbers

Length 3.7 m (estimates run from 3.5 to 3.8 m). Mass about 120 kg. Hip height about 1.4 m. That is 2.2 human-lengths, or 0.33 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Dromiceiomimus with a bus Place on the timeline