Sir David Attenborough’s landmark BBC series Kingdom is to show one of the most heart-wrenching stories in the history of wildlife programming - involving a wild dog in a valiant fight with a crocodile. But when it airs later this month viewers will also learn how the pack of dogs , followed by cameras for five years at the Nsefu park in Zambia , have a bond so strong that members are willing to risk their own lives in a rescue attempt. In the episode, the audience learns how three-legged Flint