Can snails find their way home - and over what distance?

Do snails have sat-nav?

A scientist from the University of Exeter is helping to solve one of the great gardening mysteries – do snails have sat-nav?

Dr Dave Hodgson, from the University’s School of Biosciences (Cornwall Campus), is working with Totnes-based amateur scientist Ruth Brooks to find out if snails have a homing instinct.

As part of this they’re running a huge national experiment, and are hoping people all over the country will offer to take part.

Snails are ferocious herbivores and can wreak havoc in gardens, munching their way through prize produce and causing a great deal of damage.

This leads some green-fingered enthusiasts to resort to any means necessary to keep them at bay.

Many try to humanely deal with the problem by collecting the snails and moving them to another area, but the question is — do they simply return to the same spot? If so, how far would you have to move them before they can’t find their way back to your greens?

Ms Brooks put this question forward to BBC Radio 4’s Material World programme as part of their ‘So You Want To Be A Scientist’ feature, which is aiming to find the BBC Amateur Scientist of the Year.

Her question was one of four picked to become a full-blown science research project from more than a thousand entries. Dr Hodgson from the University of Exeter has been drafted in to be her mentor through the evidence gathering process.

He said: “This is a fantastic project because this is a real issue for gardeners all over the country – how do you stop snails from eating everything you grow? Ruth’s question could help find a humane way of dealing with that.

“My job is to help oversee the science and it’s been great so far because we’re getting lots of people involved and showing them how the scientific process works. It’s not all about lab coats and maths, it can be much more accessible and fun. The more people who get involved the better.”

The next big step in the project is to hold the ‘Great Snail Swap’ experiment, which aims to get people all over the UK taking part.

It asks people to pair up to swap Helix aspersa (or garden) snails from their back gardens, marking them up beforehand to see how many snails end up returning to their original patch.

Those taking part are then asked to submit their data, including information such as how far apart the two gardens are and what obstacles are between them.

Ms Brooks said: “I’ve always wanted to know whether the snails that decimate my plants just come back when I move them, and if they do, what is their homing distance? How far away would I have to move them so they won’t come back?

“We’re hoping the evidence from this project will give us a fascinating insight into the behaviour of snails, as well as help us find a way for gardeners to deal with the problems they pose.”

Anyone wanting to get involved in the Great Snail Swap should go to the BBC Radio 4 website at to find out more about how to run the experiment.

You can see Ms Brooks’ research diary on her facebook page for the experiment at

Ruth will present the results from the great snail swap at the British Science Association Festival in Birmingham in September.

Date: 26 July 2010

Read more University News