Meet the animals who live in nature's winter wonderlands,from the polar bear mother who gives her cubs the best possible start in life to the owl that finds food hidden beneath a blanket of snow, plus the plucky penguins that huddle together to keep warm.
The final episode explores dinosaurs' extraordinary ability to survive. Featured dinosaurs include the bizarre magyarosaurus, which lived in the shadow of the biggest flying animal - hatzegopteryx - and showed an amazing adaptation to island life; and the weird nothronychus, a carnivore that gave up meat eating. This astonishing capacity to evolve into ever more diverse and bizarre forms meant that dinosaurs not only spread throughout the world, but also dominated life upon it for more than 160 million years. It was only an unprecedented extraterrestrial event that finally saw the end of planet dinosaur.
Adam Rutherford meets a new creature created by American scientists - the spider-goat. It is part goat, part spider, and its milk can be used to create artificial spider's web. It is part of a new field of research, synthetic biology, with a radical aim: to break down nature into spare parts so that we can rebuild it however we please.
Undercover cameras help to explore the world of animal intelligence, ingenuity and creativity in their hunting, protection and health. Spy Orang-utan meets her real-life counterparts in Borneo to capture how, living close to local people, they have gained unexpected skills in sawing wood and washing with soap, while Spy Termite catches one of the world's cleverest animal tricksters, the drongo, as he tries to outwit a group of meerkats in the battle for food.
Hybrids can be bizarre and they can be deadly. We look at two hybrid animals that owe their existence to human interference - the pizzly bear (a cross between a polar bear and grizzly), which has come into being because of global warming, and the killer bee, brought into existence because of the transfer of African bees to South America.