The world of the dinosaur is a tough and dangerous one. Remember the ferocious Velociraptors made famous by "Jurassic Park?" Watch as bigger versions of them, Utahraptors, take down larger prey by hunting in groups. It takes revolutionary adaptations to stay alive during the era of the dinosaur, and this episode exposes how different species changed to survive. See how a smaller version of the Utahraptor, the Rahonavis, used its special ability to run up trees to evade predators. In the skies, a young pterosaur - a flying reptile - uses flight to evade its enemy. Also showcased will be the radical discovery that mammals were much more diverse at an earlier time than previously thought. You'll see the unusual Castorocauda, a beaver-like animal, and the Volaticotherium, an animal similar to a flying squirrel - mammals who shared the earth with dinosaurs during their reign. And an orphaned Protoceratops - a cousin to the more famous Triceratops - finds safety in numbers when it joins up with a group to fight off predators.