August 4, 2010

Experiment Shows Snails Can Find Their Way Home

Public invited to take part in additional experiments

A sixty-nine-year-old amateur scientist has discovered that her garden snails have a homing instinct.

According to BBC News, the results of her experiment have wowed some professionals who previously believed that snails are far too simple creatures to find their way home.

With the help of BBC Radio 4's Material World Program, experts launched a national experiment to settle the debate over whether snails do in fact have the homing instinct.

The idea came about last year, when Ruth Brooks became frustrated with the snails in her garden after they had ravaged her plants and vegetables. She was too kind of a person to kill them, so she took them away to a nearby piece of waste land. But she found that they kept coming back.

"I really don't like killing snails with pellets or salt and I wanted to find a humane way of protecting my garden," said Brooks.

It is gardener's lore that snails have a homing instinct. But Ruth wondered if there was a scientific reasoning for this. She called Material World, who put her in touch with Dr Dave Hodgson, a biologist at Exeter University.

The two devised experiments to assess the snails' alleged homing techniques. The results suggested that snails are able to home. Brooks found that her snails were able to return to her garden unless they were placed more than 30 feet away.

The result astonished Dr Hodgson. "The conventional thinking is that snails are far too simple to be able to find their way home. So if Ruth's findings are true we'll have to rethink our theories," he told BBC News.

Ruth's results are from just one experiment. In science, it is key for researchers to perform as many experiments as necessary to ensure they have not got a fluke result.

To learn more, Dr Hodgson has invited members of the public to take part in a National "Snail Swap" Experiment.

The plan is for people to gather their garden snails in a bucket and mark them with colored nail polish -- a process he says does not harm the snails. The next step is to persuade a neighbor to do the same -- but to mark their snails with a different color. The final step is to swap buckets and wait to see if any of your snails come back.

"It could be a long process," says Dr Hodgson, "because snails aren't the fastest of creatures."

"Even if none of your swapped snails return we'd like you to enter your results online, as the data will help ecologists understand the behavior of these ancient creatures."

Ruth's study concerned only one type of snail, but there are many other species. For example, the giant African land snail, which, as an invasive species, has become a serious crop pest in Asia. This species can cover much larger areas and would have to be taken further away from its habitat to ensure it would not come back.

Experts say it would be interesting to replicate this study elsewhere to see if there really is a difference between homing behaviors of different types of snails.

If the results back Ruth Brooks' claims, gardeners will have to do more than just throw their snails over the garden fence to be rid of their pests.


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