Gallimimus was a fast, agile theropod dinosaur that lived during the Late Cretaceous period, around 70 million years ago, in what is now Mongolia. Its name means chicken mimic, but with its long legs, toothless beak, and large eyes, it more closely resembled a prehistoric ostrich. Gallimimus could grow up to 20 feet long and weigh about 400 pounds, and it was likely one of the fastest dinosaurs, capable of sprinting across open plains to evade predators. As an omnivore, it may have fed on plants, small animals, and insects. With its speed, sharp senses, and bird-like features, Gallimimus is a fascinating link in the evolutionary chain between dinosaurs and modern birds.