The “ostrich dinosaur” refers to Ornithomimosauria, a name that translates to “bird-mimic lizards” or “ostrich mimics.” These dinosaurs roamed the Earth during the Cretaceous Period, primarily across the landmasses that now form Asia and North America. They are distinguished by their striking physical similarities to modern-day ostriches, a remarkable example of convergent evolution reflecting a similar lifestyle and adaptations for speed.
Anatomy of an Ostrich Mimic
Ornithomimosaurs possessed a body plan that mirrored fast-running birds. Their bodies were slender and lightly built, supported by long, powerful hind limbs that ended in three strong toes with hoof-like claws, similar to an ostrich’s foot structure. This specialized leg anatomy, including elongated metatarsals, made them highly adapted for swift locomotion.
Their streamlined torsos supported notably long and flexible necks, which held a small head with large eyes. Most ornithomimosaurs featured a toothless beak, further strengthening their resemblance to modern birds. Evidence from fossil discoveries indicates that their bodies were covered in feathers rather than scales, adding another bird-like characteristic. Their forelimbs were long and slender, equipped with powerful claws that paleontologists suggest were used for grasping or pulling down branches.
Diet and Speed
Ornithomimosaurs were likely omnivores or herbivores. Their toothless beaks would have made tearing meat difficult. The discovery of gastroliths, or stomach stones, in many specimens points towards a diet rich in plant material, as these stones aided in grinding tough fibrous vegetation.
These dinosaurs supplemented their meals with insects and small animals they could swallow whole. Ornithomimosaurs were known for their speed. Their long legs, lightweight skeletal structure, and absence of heavy defensive armor allowed them to be among the fastest dinosaurs. This agility served as their primary defense against larger predators.
Notable Species and Discoveries
Gallimimus bullatus was a large ornithomimid that lived in what is now Mongolia during the Late Cretaceous period, around 70 million years ago. Fossils of Gallimimus were discovered during Polish-Mongolian expeditions in the Gobi Desert in the 1960s, representing some of the most complete ornithomimid material found.
Struthiomimus altus, meaning “ostrich-mimic,” is another genus, with fossils found in the Late Cretaceous formations of North America. This species was about 2.5 meters (8 feet) long and adapted for rapid movement. Ornithomimus velox, meaning “bird mimic,” also hails from the Late Cretaceous of North America and was one of the earliest ornithomimosaurs discovered. These discoveries highlight their widespread geographical distribution and evolutionary success.