There had been no conclusive evidence supporting the existence of allosaurs in Mid-Cretaceous Antarctica at the time this episode was made; it was merely based on an ankle bone found in Australia, which had been close to Antarctica in that time. This is the reason it is not given a more specific name than "allosaur" in the episode, which was a broad group of large carnivorous dinosaurs that contained the famous American and European genus Allosaurus. A decade after the episode's production, a carnivorous dinosaur named Australovenator or "Southern hunter" was described by scientists, whose parameters were similar to those of the "allosaur" in this episode. BBC themselves would then retroactively label the creature as Australovenator on their website, while the series' 2008 re-release simply named it a "carnosaur", a broader group of dinosaur predators that included allosaurs.
Features creatures in this episode: Leaellynasaura, Muttaburrasaurus, Koolasuchus, Allosaurus. This is the smallest cast of the series. The book also features the platypus-like mammal Steropodon.
Recent scientific finds have made palaeontologists re-evaluate the image of Leaellynasaura, the main dinosaur star of this episode. Its tail was actually much longer than what we see in this episode, taking up 75% of the animal's full length. What more, the animal may have been covered with a fluffy plumage.
None of the creatures depicted in this episode have been found on Antarctica, but at the time Antarctica was connected to Australia. Thus, it is feasible that they also existed on the nearby Antarctica or migrated there during its warm summer. Only one genus of dinosaur has been discovered on Antarctica itself: the Early Jurassic theropod Cryolophosaurus. Since this was an 8 m long predator, it seems likely other, as of yet undiscovered dinosaurs also existed on Antarctica at the time.