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.
The series begins in the 'land of the sabre-tooth'; North America, a continent that was half covered by ice that was up to two miles thick. Yet this frozen land also boasted the most impressive cast of Ice Age giants in the world. Across locations such as the Grand Canyon, the sands of Arizona and the coast of California, Alice traces the movements of Ice Age beasts like bear-sized sloths, vast mammoths and the strange beast known as the glyptodon. These leviathans all have one thing in common: they were stalked by the meanest big cat that ever prowled the Earth, armed with seven-inch teeth and hunting in packs - Smilodon fatalis, the sabre-toothed cat.
The annual Serengeti wildebeest migration is a journey so fraught with peril, it's a wonder they set off at all. For wildlife expert Jean du Plessis, it's a unique chance to see how a new generation of calves, born just months ago, will fare among the predatorial lions and crocodiles that await them.
This is the story of two young animals forced to grow up fast. In Africa's savannah, a baby elephant shrew learns how speed is the secret to survival amongst the largest animals on Earth; and in America, a young grasshopper mouse confronts the Wild West's deadliest creatures to stake a claim of his own.
The savannah is home to some of the greatest herds on Earth, and in this episode, Wild Africa brings you close encounters with these animals. The savannah is Africa's youngest landscape, shaped by the weather and the animals themselves as the continent dried. It is now home to baboons, wildebeest, lions, cheetah, and aardvarks who must struggle through the eight-month dry season to survive.