The first episode of Walking with Beasts, this episode shows the Early Eocene Epoch.

Set in the dark, steamy and mysterious global forest of 49 Million Years Ago, this episode is set in the particular region associated with the Messel Shales of Germany. In this time, though the dominating force of the Dinosaurs and other giant reptiles had been over for well over 16 Million Years, Mammals still did not have it there way - the direct successors to the Non-Avian Dinosaurs were the Avian Dinosaurs. In effect, the rule of Dinosaurs was still in force; albeit in the form of far smaller - yet still utterly terrifying - giant Terror Birds, such as Gastornis. Mammals scurry about under the sharp gaze of the monstrous birds. For the first and only time in their evolutionary history, birds, rule the world.

This episode features Leptictidium, Ambulocetus, Gastornis, and several other creatures.