Mesozoic that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Dinosaurs appeared in the Late Triassic and became the dominant terrestrial vertebrates early in the Jurassic, occupying this position for about 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic, having evolved from a branch of theropod dinosaurs. The first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg (33 lb)—until the Cenozoic.
Dinosaurs: Giants of Patagonia Dinosaurs: Giants of Patagonia Dinosaurs: Giants of Patagonia is a 2007 film about life in the Early Cretaceous, Patagonia. It features paleontologist Rodolfo Coria and his work, with Donald Sutherland acting as main narrator. The movie opens on a scene from approximately 65 million years ago, in the Late Cretaceous. The narrator explains that a massive comet is about to arrive to mark the end of dinosaurs, before taking us back to the Late Jurassic, circa 150 million years ago. From the announced end of the dinosaurs, this time travel serves the purpose of introducing us the biggest creatures to