Man's Heritage: The Lost Elephants Of Timbuktu Pearl, 8.30pm Legend has it that an elephant never forgets. And that's a valuable trait for the herd featured in this BBC documentary. The lost elephants of the fabled city of Timbuktu, Mali, survive in Africa's harsh Sahara Desert by recalling the location of the country's few and far between watering holes. Living in one of the most arid places on Earth forces them to make a gruelling yearly migration of more than 1,000 kilometres in search of water. They are joined in their quest by the nomadic Tuareg people, in a remarkable example of co-existence that is centuries old. The Tuaregs' goats graze in the giants' shadows and, at night, the elephants dig water troughs to share with their human travelling companions. The most intriguing aspect of this relationship, however, is that every June, the elephants disappear through a narrow mountain pass. The Tuareg have never followed them. This film does.