Quetzalcoatlus is one of the largest known flying reptiles. Although many Jurassic and Cretaceous ecosystems featured large predatory dinosaurs far exceeding the size of any modern terrestrial predator, few pterosaurs reached the enormous size of Quetzalcoatlus. So, how did Quetzalcoatlus grow so large, and why did so few other pterosaurs achieve similar dimensions? This video aims to answer these questions.