Overview
Gallimimus bullatus was a swift, ostrich-like theropod
dinosaur that lived during the Late Cretaceous in what is now
Asia (Mongolia). Fossil evidence suggests
long, slender limbs and a toothless beak adapted for
an omnivorous diet. Weighing around
500 lbs and reaching about
20 ft in length, Gallimimus may have sprinted
up to 35 mph.
Frequently compared to modern ostriches, Gallimimus possessed
lightweight bones, a flexible neck, and a relatively small head.
These features, combined with its substantial leg length, allowed it
to evade predators or forage rapidly. Paleontologists believe
Gallimimus likely fed on plants, small animals, and possibly insects.
Quick Facts
Diet
Omnivore (plants, insects, small animals)
Speed
Up to ~35 mph (est.)
Weight
~500 lbs (~227 kg)
Bite Force
~200 psi (estimated)
Discovery & Significance
First described in 1972 by paleontologists Osmólska, Roniewicz,
and Barsbold, Gallimimus remains iconic for demonstrating
the diversity among theropods beyond large carnivores. Specimens
from the Nemegt Formation of Mongolia highlight the genus’s
advanced locomotor features and potential group behavior.
Gallimimus has helped paleontologists understand convergent evolution
between dinosaurs and modern flightless birds—both in overall body
shape and likely social dynamics. Its depiction in popular culture
often emphasizes speed and flocking behavior, reflecting hypotheses
that it may have roamed in herds, seeking safety in numbers.
More Details
Discovered in the sandy expanses of Mongolia’s Gobi Desert during Polish-Mongolian expeditions in the 1960s, this creature remains one of the best-known “ostrich-mimic” dinosaurs. Standing about 1.9 meters (6 ft 3 in) tall at the hip and stretching 6 meters (20 ft) from snout to tail, adult Gallimimus likely weighed somewhere around 400 to 490 kilograms (880 to 1,080 lb). Its snout was broad and toothless, topped by a keratinous beak, while its eyes sat to the sides, keeping an eye out for danger—much like modern birds.
Along its neck and trunk, Gallimimus bore many vertebrae that were hollow, hinting at air sacs much like those of living birds. This pneumaticity helped lighten its frame, allowing for remarkable speed; some estimates suggest Gallimimus could run at up to 42–56 km/h (29–34 mph), a handy asset in a world filled with fearsome predators such as Tarbosaurus and other carnivores. Though its arms were relatively short and delicate, Gallimimus compensated with powerful hind limbs and an arctometatarsalian foot structure—where the middle toe was pinched between its neighbors—to support swift, efficient strides.
Debate flourishes about its diet. Early views portrayed it as an opportunistic omnivore, snatching small prey much like a modern gull. Others noted the possibility of filter-feeding, spurred by the presence of tiny ridges or “columns” inside the beak that could sift food from sediment. Still more recent work suggests a herbivorous leaning, akin to ostriches that graze on vegetation. Whichever the case, Gallimimus’ elongate neck and mobile head likely allowed it to forage across a range of habitats, all while maintaining the agility needed for a quick getaway.
Popular culture immortalized Gallimimus in the film Jurassic Park—where a stunning stampede scene showcased the dinosaur’s graceful, flocking behavior. Even decades later, Gallimimus continues to stand as a prime example of how bird-like some non-avian dinosaurs truly were.