Snails’ Homing Instincts Put to the Test

It’s a fact that I’d thought widely known in gardening circles—snails return to feast on your vegetables even after you’ve chucked them (the snails, that is) over the fence into your neighbour’s garden (though, of course, no responsible gardener does that).

Over the years, I’ll wager that quite a few gardeners have marked snails’ shells with paint or Tippex, sent them flying, and had a moment of bitter satisfaction when they later found said snails finishing off the broccoli. However, it's a subject that has now caught the scientific world's attention.

When BBC Radio 4’s Material World asked for projects for their “So You Want to Be a Scientist” feature, aimed at finding the BBC Amateur Scientist of the Year, Ruth Brooks, snail-pestered gardener, asked Do snails return when you remove them, and from what distance can they find their way back? It was one of four projects chosen for research from over a thousand entries.

Ms Brooks has already performed her own experiments. Her results indicate that snails return up to a distance of ten metres, so if you’re lobbing them over the fence, you probably need to throw a bit harder.

Dr Dave Hodgson, of Exeter University, who is overseeing the research, is astonished by Ruth’s conclusion and is quoted on the BBC website as saying, “The conventional thinking is that snails are far too simple to be able to find their way home.”

That’ll be conventional thinking by those who aren’t gardeners, obviously.

Still, to prove conclusively that Ruth hasn’t encountered exceptionally talented snails, we are all being invited to take part in a National Snail Swap, involving marking a bucketful of snails with nail varnish, swapping them for a bucket of a friend’s snails (differently marked), letting them loose in your respective gardens and waiting to see if any make it “home”.

This could be a good project to keep kids out in the garden for the summer, so if you want to take part,you'd better be quick and visit the Radio 4 website, where you can also read the original proposal, download instructions on taking part and listen to relevant audio clips, including one from Gardener’s Question Time. Your results have to be submitted before 31st August and will be reported on Material World in September.