S1·E9 The Rise of the Mammals

Mammals have proved to be one of the most adaptable products of evolution. David Attenborough looks at their evolution from reptiles 200 million years ago. This remarkable transition involved the development of mechanisms for regulating body temperature, for allowing the young to develop in the womb and for suckling newborns. Attenborough also explores the South American origins of marsupials and their colonisation of Australia.