The third episode looks at the last generation of killer dinosaurs - carnivores that took killing to a new level. By the end of the cretaceous period - 75 millions years ago - these gigantic and specialised hunter-killers had spread throughout the globe. In the southern continents it was the powerful and muscular abelisaurids that reigned supreme but it was the famous tyrannosaurids (or tyrant dinosaurs) that dominated in the north. Whilst the northern daspletosaurus hunted in gangs, using its highly developed smell and hearing to take down opponents like the horned rhino-sized beast, chasmosaurus, in the Southern hemisphere the small-skulled majungasaurus reigned. And though the sharp toothed majungasaurus was an efficient killer of the much smaller feathered rahonavis that did not stop it from occasionally turning cannibal and hunting its own.
The journey begins on the Galapagos' west side at the youngest and most volcanically active islands in the archipelago, Isabela and Fernandina, which are home to a richly diverse wildlife scene. Here, Liz and the team journey into the clouds above Wolf, the tallest volcano in the Galapagos, where they join a group of biologists hunting for the elusive pink iguana, which teeters on the edge of extinction. But how and why did it come to live on the top of a volcano? Back on the research vessel, Liz boards Alucia's Triton submersible to descend a kilometre into the ocean abyss in search of a new species hiding in the darkness. Liz also travels to one of the most remote locations in the Galapagos, Alcedo Volcano, in search of the largest population of giant tortoises. Plagued by drought in recent months, scientists are keen to find out how this prehistoric species has fared. Finally, Liz helps out with a groundbreaking science experiment to x-ray marine iguanas that have so far stunned the scientific community with a new mutation. As with all life on these remote islands, the key to survival is adaptation.