In Kipling's tale, the elephant got his trunk from a crocodile on the banks of the great grey-green greasy Limpopo river. But does science understand how the trunk really evolved? Vivienne talks to researchers Kathleen Smith and her husband William Kier about the wonders of muscular hydrostats (trunks, tongues and tentacles to you and me) whilst vet Jon Hutchinson ponders the elephant's aquatic origins. Last of the series. The reader is Samuel West. Producer: Rami Tzabar Show less