Walking with Beasts

The incredible story of how mammals took over from the dinosaurs as the largest, fastest and fiercest creatures on Earth. The mammals triumph was a roller coaster ride as they faced one of the most turbulent phases in Earth's history. At a time when birds ate horses, the mammals had to fight for their very survival.

This behind-the-scenes special details the science behind the evolution of the primates and the rise of the human race to dominance. In the process, the program attempts to answer an age-old question: was man behind the last great extinction after the Ice Age?

15 million years after the end of the Age of Dinosaurs, Earth has recovered from the massive meteor impact. Rainforests dominated the early Eocene, and the planet has a warm, tropical climate. It is this age that the mammals begin to thrive and spread, taking over niches left vacant by the death of the dinosaurs. But it is the birds that dominate this period in Earth's history, and they are almost all killers. But in the water, the first evidence of the mammal's destiny has appeared!

The late Eocene is a time of great change, but not a pleasant one for Earth's life form. Antarctica has separated from the other continents and is slowly freezing, changing the ocean currents. This is playing havoc with the climate, creating environmental disasters worldwide. Into this world has evolved the most fearsome whale ever to live; Basilosaurus. With ocean food stocks in chaos, a female Basilosaurus must search her home in the Tethys Sea from north to south, to satisfy her enormous hunger. And she is also pregnant...

It is now the Oligocene period, and the massive change in climate claimed 1 in every 5 species. The great tropical forests and plains that dominated the Eocene have shrunk, hanging on in the equatorial regions. In Mongolia, a seasonal desert now dominates the land, populated with some of the largest beasts ever to roam its landscape since the days of the dinosaurs. The are Hyenadon, predators as big as modern rhinos; Entelodonts, mean spirited pigs just as big; and largest of all, the massive Indricotheres, a species of rhino that was the biggest land mammal ever!