The Ornithomimus dinosaur of genus Ornithomimus and family Ornithomimidae lived in the Late Cretaceous period in North America, Mongolia, and Canada. The dinosaur had hollow bones, a small toothless beak, small ostrich-like wings and legs, a long tail, and a skull. Since its beak didn't have teeth it could only eat soft and small things. The dinosaur diet consisted of insects, fruit, leaves, eggs, lizards, and the meat of small mammals. They had a large hollow in the skull which had a bigger brain than other terrestrial dinosaurs. Its name means bird mimic and refers to bird-like feet and was named by O. C. Marsh.
Ornithomimus, the bird mimic dinosaur, is pronounced as 'or-nee-thoh-my-mus' and is named by O. C. Marsh.
Ornithomimus is classified as Dinosauria, Saurischia, Theropoda, Ornithomimosauria, Ornithomimidae, and Ornithomimus. Its type species is called Ornithomimus velox.
The Ornithomimus lived on Earth during the Late Cretaceous period around 76-66 million years ago.
The Ornithomimosauria dinosaurs became extinct during the Late Cretaceous–Paleogene period mass extinction at the end of the Mesozoic Era. The mass extinction took place around 66 million years ago when a large meteor or comet hit the earth.
Ornithomimus skeleton fossils have been found in North America (Denver), Mongolia, and Canada not sure if it was endemic to a particular place.
Details about the Ornithomimus habitat are not known yet, only the locations of the fossils and possible places where they have lived during their time. These dinosaurs could have lived in grasslands and woodlands which have an ample supply of small animals and plants to live on and supplement their diet as an omnivore.
Ornithomimus dinosaurs were gregarious species that lived in herds. The fossils were discovered in groups of adults and juveniles; with fewer adults than juveniles. The groups were probably formed for the protection of the young from predators rather than social reasons.
The exact lifespan or age of an Ornithomimus is not known. Very little information is available regarding their lifespan or life cycle. It is assumed that they have three life stages; juvenile, sub-adult, and adult, in which distinct changes occur in their physical characteristics and Ornithomimus size.
Very little information is available on Ornithomimus reproduction. They had a particular breeding season and like other dinosaurs and laid eggs like modern-day birds. The eggs were laid by the female and the juvenile dinosaurs hatched from the eggs after the incubation period.
Species of Ornithomimus have feet with three weight-bearing toes, thin and long arms, long neck ending with a bird-like, elongated, toothless, beaked skull. They resembled an ostrich and can consider ostriches cousins. Their hind limbs were very long, with hollow bones (like birds), and large brain and eye cavities. The Ornithomimus brains were large compared to other non-avialan dinosaurs. In their case, the large brains were not considered a sign of intelligence but rather were dedicated to the kinesthetic coordination required for their swift movement. The bones of the front limbs have a sloth-like appearance which led scientists to believe that the hands were used to hook onto branches while feeding. They use their tail for balance when they run at high speeds. Compared to other ornithomimids, Ornithomimus has shorter torsos, long slender forearms, and slender claws on front and hind limbs with the fingers and metacarpals having similar lengths. Both juveniles and adults had feathers on their bodies; juveniles had smaller wings. The adults had wing-like structures, which could have been used for mating displays. Initially, the Ornithomimus feathers were discovered to be pennaceous but later it was concluded that similar fossil imprints and traces would be left by monofilamentous wing feathers. The dinosaurs also have feathers along their tail according to the fossil found in Dinosaur Park Formation. The dinosaur has bare skin from mid-thigh to its feet, devoid of feathers and scales.
The exact number of Ornithomimus bones is not known yet, but many partial Ornithomimus fossils have been found in North America, Canada, and Mongolia.
Like other dinosaurs, it can be assumed that the Ornithomimus dinosaur communicated using their bodies, slender limbs, and vocalization. Dinosaurs can create distinct open-mouthed sounds and closed-mouthed sounds. The close-mouthed sounds of a lower frequency could travel long distances, which helped them communicate with the rest of the herd or warn rivals of their territory. Ornithomimus adults also have wing-like structures which were possibly used in mating displays.
The two known Ornithomimus species, Ornithomimus velox, and Ornithomimus edmontonicus differ in size. The total length of Ornithomimus edmontonicus is estimated at 12 ft (3.65 m), the femur is 18.4 in (46.7 cm) long, and the metacarpal is 3.3 in (8.4 cm) long. The Ornithomimus velox is slightly smaller, its metacarpal specimen was 2 in (5.08 cm) long.
The Ornithomimus could run very fast. It was a bipedal dinosaur with very strong hind legs and a large brain with areas dedicated to kinesthetic coordination. Its speed is expected to be more than 43 mph (69.2 kph). Its high speed is another reason why it is considered an ancestor of ostriches.
The Ornithomimus weighed moderately for its size. Its weight was concentrated in its body. It weighed 370 lb (167.8 kg).
The male and female species of this dinosaur were simply named male Ornithomimus and female Ornithomimus. They didn't have any specific names to differentiate between them. While many dinosaurs exhibit sexual dimorphism, it remains unclear whether Ornithomimus does. Sexual dimorphism usually helps in distinguishing between the sexes.
The baby Ornithomimus were simply named baby or juvenile. They did not have any specific names. As it grew it was called juvenile, sub-adult, and adult.
The Ornithomimus was an omnivore whose diet includes insects, fruit, leaves, eggs, lizards, and small mammals. They have small beaks without teeth and use their long fingers to hook onto branches while fishing. They can eat meat from small animals and insects but not larger animals since they lack teeth and have long necks.
Considering these bird-mimic Ornithomimidae dinosaurs were herbivores or omnivores, these dinosaurs aren't very aggressive. They usually don't harm other dinosaurs and since they are moderately sized, they can be preyed on by other dinosaurs like Tyrannosaurus rex.
Sometimes other dinosaur species are falsely classified as the Ornithomimus bird mimic, such as the Ornithomimus samueli specimen discovered in Dinosaur Park Formation, Alberta.
The specimen CMN 8632 found in the Horseshoe Canyon Formation of Alberta was named Ornithomimus edmontonicus.
Many specimens could not be classified as either Ornithomimus or Struthiomimus. Thus, two new genera were created; Archaeornithomimus and Dromiceiomimus, which was also a bird mimic whose name meant 'emu mimic'.
The dinosaur was named Ornithomimus by O.C. Marsh. Ornithomimus name means 'bird mimic', derived from Latin words 'ornis' which means 'birds' and 'mimos' means 'mimic', which refers to the bird-like skull, foot, toes, long neck, and toothless beak. The type species name means 'swift' in Latin.
The omnivore Ornithomimus of class Theropoda lived during the Late Cretaceous period 65 million years ago. The dinosaur fossil was discovered in North America, Mongolia, and Canada. Very little information is available on the habitat or environment of the Ornithomimus dinosaur. Since its diet consists of insects, fruit, leaves, eggs, lizards, meat, and small mammals, it probably lived in grasslands and woodlands where they have a wide variety of prey. Since they had a plumage of feathers, they might live in cooler areas.
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Second image by DinoTeam.