First, hear about fish-shaped reptiles that thrived in the oceans while dinosaurs ruled the land. Then, learn about the evolutionary history of whales, the mammals that conquered the seas. The most famous of all dinosaurs, Tyrannosaurus Rex, gets a fresh look as scientists re-examine fossil evidence for clues as to the tyrannosaur¿s actual behavior. Also, learn about some ancient Australian marsupials that were as ferocious as they were bizarre. Then, in "Which Came First, the Feather or the Bird?" hear about the carnivorous bipedal dinosaurs that developed the earliest feathers. Also, "Terror Birds of South America," huge creatures that were the dominant carnivores on the continent for millions of years, until competitors drove them into extinction. Finally, get an overview of the "Evolution of Life on Earth."