It would have been inhabited by mammoths, rhinos, hippos, giant deer and bison, which were preyed upon by sabre-toothed cats, lions, wolves and hyenas.
Episode three looks at what could have caused mammoths, woolly rhinoceros, sabre-toothed cats, giant ground sloths and glyptodons to finally go extinct.
These cat-like species included the false sabre-toothed cats, or nimravids, and a family of cat-like carnivores called barbourofelids which died out several million years ago.
