PBS writes “The remains of medium-sized predatory dinosaurs are pretty rare in places where giant predators like T. rex existed. Which is weird, because that’s just not how ecosystems work today.”
Where Are All the Medium-Sized Dinosaurs?
Death of the dinosaurs. Artist's impression of a pair of giant dinosaurs being startled from their sleep by the blazing fireball of an incoming asteroid or giant meteor. The dinosaurs died out 65 million years ago, along with thousands of other life-forms, at the end of the Cretaceous Period. The theory that the mass extinction was caused by the impact of an extraterrestrial body has recently received support from geological evidence, though numerous other explanations for the death of the dinosaurs have been put forward.