In the humid Sava region of northern Madagascar, where vanilla vines grow in the shaded canopy of the jungle, villagers guard their crop as though it were a precious metal. Well they might. Strong demand for natural vanilla, speculation, bad harvests and money laundering have driven prices as high as silver. Farmers often awake to find their vines stripped bare, carried off in the night by gangs of thieves filling orders for buyers in the far-off capital of Antananarivo, who in turn supply the markets of western Europe, the US and Asia. In some parts of Sava, say non-governmental organisations working in the region, vigilante groups have sprung up to mete out summary justice to the vanilla snatchers.