National Geographic Documentaries - Weirdest Dinosaurs

Seizoen: 2015 - Aflevering: 23 / 1405 - Eerst uitgezonden: 09 juni 2015 - Episode ID: 1162741

As dinosaurs grew into the behemoths of the Cretaceous period they evolved many extraordinary but apparently useless features including spikes, sails horns, crests and the tiny "arms" of tyrannosaurs. The program reviews these unusual features and discusses theories of why they exist.