The reptiles evolve, and the race for survival continues on land. Giant arthropods lurk in the Carboniferous forest, and sail-backed mammal-like reptiles fight for the survival of their young in the Permian.
Did You Know?
The giant spider that appears in the first segment of the episode is referred to as "Mesothelae", which is although not a proper name of a specific genus or species, the series tends to refer to a number of animals by the name of the animal group they belong to. Originally, this Mesothelae was meant to be a Megarachne, possibly the biggest spider ever discovered, until during the series' production, it turned out that "Megarachne" wasn't a spider at all, but an eurypterid (or sea scorpion). By this time, though, since the production was already underway, all they could do was to change the name of the spider. The error was not fixed completely, though, as (now that Megarachne has been re-classified) there is no evidence of any spider being as large as the "Mesothelae" depicted in this program. See more
When the Dimetrodon appears, you can still see the Sun's rays shining even after it has blotted out the Sun itself with its large back-sail. Normally, when the light-emitting object is covered, its rays also "disappear". See more
Kenneth Branagh - Narrator
Three hundred million years ago, much of the Earth was covered in vast swamp forests. Here nothing is as it seems.