Ornithomimids

Diet

Ornithomimids probably acquired most of their calories from plants. Many ornithomimosaurs, including primitive species, have been found with numerous gastroliths in their stomachs, characteristic of herbivores. Henry Fairfield Osborn suggested that the long, sloth-like 'arms' of ornithomimids may have been used to pull down branches on which to feed, an idea supported by further study of their strange, hook-like hands. The sheer abundance of ornithomimids — they are the most common small dinosaurs in North America — is consistent with the idea that they were plant eaters, as herbivores usually outnumber carnivores in an ecosystem. However, they may have been omnivores that ate both plants and small animal prey.