Overview: Chris Packham explores the anatomy and physiology of the largest land animal on the planet - the elephant. Their size seems ill-suited to surviving the most arid regions of Africa, but their inner workings allow them to defy the extreme heat of the desert and find food and water in seemingly barren landscapes, while their extraordinary memory enables them to repel predators. Chris reveals how hairs on the skin help keep elephants cool, how sensors in their feet may be able to guide them towards rain and how a unique pouch in their mouths stores water. Recent research has even discovered that elephants can distinguish between the voices of human friend and foe.