65.5 million years ago, Late Cretaceous (Montana)
Filming location: Chile, New ZealandThis episode starts months before the extinction of the dinosaurs. The last dinosaurs are depicted living under intense environmental stress due to excessive volcanism. Many of the dinosaur and pterosaur species still in existence are the largest and most developed of their respective genera, including Ankylosaurus, Quetzalcoatlus, Triceratops and Tyrannosaurus. The story focuses on a female Tyrannosaurus who abandons her nest, the eggs rendered infertile due to volcanic poisoning. Her calls for a mate are answered by a smaller male who kills a young Triceratops to appease her. Three days later, after repeated copulation and theTriceratops carcass being stripped, she eventually drives him off. The mother fasts for an extended period as she tends to her nest, dealing with raids by Dromaeosaurus and marsupialDidelphodons. As the female tends to her vigil, herds of the hadrosaur Edmontosaurus wander from islands of vegetation among fields of volcanic ash, while Torosaurus rut for the right to mate and lose their young to attackingDromaeosaurus. Meanwhile, the mother Tyrannosaurus sees only three of her twelve eggs hatch and brings down an Edmontosaurusto feed herself and her brood. While defending her two surviving offspring several days later, the mother is fatally injured by anAnkylosaurus who swings its clubbed tail at her right side; the blow cracks her femur and ruptures internal organs. The chicks remain expectantly next to the carcass of their mother the next morning until they, and the rest of the non-avian dinosaurs in this region, are killed when an asteroid slams into the Earth, a catastrophe that triggers the Cretaceous–Paleogene extinction event. A final short sequence shows the African plains on the present-day Earth, dominated by the large African mammals of today, but still populated with numerous forms of dinosaurs: the birds.Animals Tyrannosaurus · Edmontosaurus (identified as Anatotitan) · Ankylosaurus · Deinosuchus · Didelphodon ·Dinilysia · Dromaeosaurus · Quetzalcoatlus · Torosaurus · Triceratops (carcass) · unidentified Hypsilophodont