Snails on forced march

For a creature that carries its house on its back, the need for a homing instinct might seem a little redundant.

But for the first time scientists have proved snails have their own territories and will try, albeit very slowly, to make their way back if moved elsewhere.

In an experiment designed for the BBC4's new wildlife programme, The British Garden: Life and Death on Your Lawn, Dave Hodgson, of Exeter University, collected 65 snails from four corners of a garden in Hertfordshire.

He painted them bright fluorescent colours, depending on which corner they came from, before placing them in the middle of the garden.

A fifth group, from Cornwall, was added and painted bright green.

The snails were videoed overnight to find out if they would travel back to their flower-beds. Snails can move at about 1.6m/h at full throttle - about 38m in 24 hours.

"Interestingly, the Cornish ones headed due west: extraordinarily, in the right direction," said Hodgson.

"In the blue corner, almost all of the snails I found were blue snails. In the red corner, almost all of the red snails found their way back. In the orange corner almost all were orange and, of the pinks, almost all of them were back in the pink corner.

"This is spectacular evidence for homing instinct in the garden snail."