Imagine a National Geographic survey of a natural world that hasn't existed for millions of years. The sequel to the mesmerizing Walking with Dinosaurs, one of the most imaginative explorations of the prehistoric world ever made, once again uses the technology of the Jurassic Park fantasies to re-create the "menagerie of weird and wonderful creatures" that roamed the globe after the dinosaurs. Designed as a series of survival dramas, each of the six episodes plays like a speculative Disney True Life Adventure (with appropriately resolute narration by Kenneth Branagh) centered around a day in the life of a creature or the seasonal cycle of a species: a pride of saber tooth cats, a herd of woolly mammoths, a tribe of hominids. It's all supposition, of course, but it's supposition based on the best research available. The BBC production, which does not shy away from this violent world, includes computer-animated footage of mating and hunting techniques. However, any prehistory fan 7 or older should enjoy this series. --Sean Axmaker