Today we have five species of big cat, in the past there have been 30 and Nigel decides to rescue the most famous extinct prehistoric feline of all: the Sabre Tooth. Often referred to as the Sabre Tooth Tiger, this is incorrect as the creature was not a tiger but a big cat. Three million years ago the Smilodon, or Sabre Tooth, was top predator in North America and, when the landmasses of North and South came together, it entered the territory of South America’s top carnivore, the Phorusrhacid or Terror Bird: a three-metre tall flightless flesh eater!

Nigel travels back 10,000 years to the end of the Great Ice Age when Britain was still attached to Europe. As the Earth warmed up it forced the last remaining mammoths back to colder, more remote places like Siberia. Weighing in anywhere between four to six tonnes these herbivores needed plenty of grass and shrubs to sustain their huge bulk and with the Earth warming, forests were overwhelming the grasslands, denying them vital food and threatening their survival. But as Nigel finds out, it wasn’t just the climate that threatened these once highly successful creatures.

In his most dangerous mission to date, Nigel has decided to travel back to prehistoric Texas, 75 million years ago, to find and bring back a colossal 50-foot long Cretaceous crocodile: Deinosuchus. There were more species of dinosaur alive at this point in prehistoric North America than at any other time, so Nigel's quarry won't be the only predator stalking the shoreline...

Insects and other invertebrates have always fascinated Nigel and the remote Scottish Island of Arran offers him some clues about one of the Park’s next guests. The rocks of the island date back some 300 million years and reveal fossilized tracks of an Arthropleura: a giant arthropod, much like our millipede and centipedes today, only this one grew to the size of a man. Not only giant centipedes but also oversized scorpions and dragonflies populated a hot and boggy Scotland, which, at that time, sat on the Equator.

Nigel travels back 65 million years to track down the devastating predator and undoubted king of the dinosaurs: the Tyrannosaurus rex. His search begins in Montana, North America, where many fossilized remains of this formidable creature have been found. Montana would look a strange place to us now; grass would not evolve for another 30 million years and volcanoes dominated the landscape, but you would recognise the trees – the Monkey Puzzle, we still have them today and that pretty much makes them living fossils!

Nigel now decides to pay a visit to the China of 125 million years ago: the early Cretaceous period. It was here that experts made a recent and extraordinary discovery: a tiny fossilized dinosaur with feathers. They have called the creature Microraptor, giving the scientific community its strongest evidence to-date that birds are the direct descendants of dinosaurs.