It's like killing two birds with a single stone. Researchers have found that African farmers are using bees to save their crops from elephants, and also making a fast buck from the honey. The bees attack anything that threatens their hives. Angry swarms are reputed to have chased herds of elephants over several kilometres. Elephants too avoid all those trees that have beehives hanging on them, say Fritz Vollrath of the Kenya-based Mpala Research Centre and, Ian Douglas-Hamilton of the Nairobi-based conservation organisation Save the Elephants.

During their study in Kenya, they found that even empty hives were enough to reduce elephant damage, probably through their smell. On the other hand, more than 90 per cent of trees which were without beehives had branches ripped off and bark stripped. "Beehives would be much cheaper than fences,' says Ian Redmond, a uk-based expert on African wildlife and conservation.