'If we stopped poaching tomorrow, elephants would still be in big trouble'

Ivory poaching is the most immediate, urgent threat to Africa's elephants. But even if that can be tackled, they will have to fight humans for land, food and water

It is the dead of night. The day's red-dust heat has given way to a cooling breeze. A hundred frogs chirp urgently. Tim and his crew are preparing for another stealth raid. Their mission is highly dangerous and now there's a new threat: armed men are following them.

This is the scene repeated nightly on the eastern fringes of Amboseli national park in Kenya, close to the border with Tanzania. Tim is an elephant who, along with a group of up to 12 other males, has developed a taste for the tomatoes and maize growing on local farms on the outskirts of the park. The armed men are park rangers who have been tasked with keeping him from the crops - and saving his life.