Walking with Dinosaurs is a 1999 six-part nature documentary television miniseries created by Tim Haines and produced by the BBC Science Unit, the Discovery Channel and BBC Worldwide, in association with TV Asahi, ProSieben and France 3. Envisioned as the first "Natural History of Dinosaurs", Walking with Dinosaurs depicts dinosaurs and other Mesozoic animals as living animals in the style of a traditional nature documentary. The series first aired on the BBC in the United Kingdom in 1999 with narration by Kenneth Branagh.

Spirits of the Ice Forest - Spirits of the Ice Forest is the fifth episode of Walking with Dinosaurs, set in the middle Cretaceous epoch, roughly 106 MYA. A few hundred kilometres from the South Pole, a clan of Leaellynasaura emerge during spring after several months of total darkness. They feed on the fresh plant growth (which has adapted to the changing seasons), and build nests to lay their eggs; a male Koolasuchus also wakes and heads to a river, where he will stay during the summer. Out on the banks of the river, migrating herds of Muttaburrasaurus have also arrived to feed and lay their eggs. When summer arrives, many of the Leaellynasaura clan's eggs have been eaten; however, those of the matriarch hatch successfully. Meanwhile, a male polar allosaur hunts both the Leaellynasaura and the Muttaburrasaurus, the latter species also having to deal with blood-sucking insects. When autumn arrives, the Muttaburrasaurus herd begins to migrate, and the Koolasuchus leaves the river to find a pool for hibernation. During the migration, some Muttaburrasaurus become lost in the forest; they vocalize loudly while trying to return to their herd, preventing the Leaellynasaura clan's sentries from hearing the polar allosaur approaching. It manages to kill the matriarch of the clan. Winter descends and the forest is shrouded in darkness, but the now matriarch-less Leaellynasaura clan is able to stay active, using their large eyes to help them forage for food. The clan and other creatures are also shown to use various methods of coping with the cold such as being frozen alive or suspended animation. Finally, spring returns, and two Leaellynasaura males challenge each other for the right to mate, and the clan establishes a new dominant pair. The closing narration states that continental drift will soon pull this landmass closer to the South Pole, and when that happens, this unique ecosystem will disappear.