Gallimimus, meaning “fowl mimic”, is a genus of dinosaur from the Late Cretaceous Period (Maastrichtian age) found in the Nemegt Formation in Mongolia. It was discovered in the early 1970s in the Gobi Desert and never shortly after its discovery. The only known species is G. bullatus. A second species discovered was never confirmed as a member of this genus. Multiple individuals have been recovered ranging from juveniles up to adults.
The adult Gallimimus was about 13 feet in length and weighed as much as 970 pounds. It stood close to 7 feet tall at the hip. It is one of the largest ornithomimosaurs to be discovered. This was an ostrich-like dinosaur with a small head and large eyes. It had a long neck, short arms, long legs, and a long tail. A characteristic of Gallimimus is the relatively short hand in comparison to the length of the humerus (in relation to other ornithomimids). It used its long tail as a counter balance. The eyes were located on the sides of the head, meaning that it did not possess binocular vision. The bones were hollow, like most modern birds. There are characteristics of this dinosaur that indicate it was a quick runner. Long limbs and short toes are the likely reasons for it to be a quick and agile runner, however it is not known how fast it could run.
Ridges found on the beak of the Gallimimus indicate that it may have been a filter feeding animal much like a duck. However, similar ridges that are seen in sea turtles and other ornithomimids were fairly common in seasonally dry environments where filter-feeding was not a viable lifestyle. It is more likely that Gallimimus was an omnivore, using its beak to crop plants and capture small animals.