Walking with Prehistoric Beasts

For 160 million years dinosaurs have ruled the world, while mammals have lived in their shadow. Then a meteor crashes into the Earth wiping out the dinosaurs. 15 million years on, the world has changed. Birds, reptiles, mammals and insects live together waiting to establish a new order.

The mass extinction event that saw the demise of the dinosaurs was almost as devastating in the seas. The oceans were emptied of almost all large animals and carnivorous creatures. 30 million years after the dinosaurs, the top of the ocean food chain is now occupied by an early whale: Basilosaurus.

For 40 million years forests have dominated the world, helping mammals evolve, but the world is changing. The forests are punctuated by open plains. With the constraints of living in the forest lifted, evolution has produced the largest land mammal that ever lived, the Indricothere.

In Ethiopia, a world of grassy savannah and forests, live zebra, wildebeest , gazelles, Deinotheriums - a giant type of elephant with inward facing tusks - and a species of ape. This ape shows signs of early humankind. This ape can walk on two legs.

For years, South America was separate from the rest of the world. Animals that evolved there were unlike those found elsewhere on Earth. But 2.5 million years ago, a land bridge connected North and South America and the Smilodon, the largest saber-tooth cat ever, crossed the bridge.

Northern Europe is a scene of grassy plenty, where many animals spend the brief Ice Age summer gorging on vegetation. Among them are the mammoths. This program follows one particular herd as they migrate to greener pastures.