Researchers say that despite their lethargic reputations, snails can travel at a relatively speedy one metre per hour. By attaching multi coloured LED lights, the scientists were able to track their movements over a 24-hour period. The gastropods were fast enough to explore the length of an average garden in a single night. But scientists are worried that the fast-moving snails are spreading a parasite that is deadly for dogs.
According to the Royal Horticultural Society, their numbers increased by 50% last year. As well as being a pest for gardeners, snails can also spread a parasite called Angiostrongylus vasorum. This lungworm is a particular threat to dogs, which can become infected by accidentally eating slugs or snails which they come across in the garden or on dog toys.
Researchers at the University of Exeter were commissioned to look into the scale of the threat by the Be Lungworm Aware campaign, which was set up and funded by Bayer Animal Health. The scientists attempted to track the movements of snails in garden situations. To do this they attached tiny, multi coloured LED lights to the backs of about 450 snails and used UV paint to track their movements. The researchers found that the snails could cover distances up to 25m in a 24-hour period.
The lungworm parasite can be fatal in dogs and researchers say it is spreading. "They are so slow that people don't even think about them moving, but it turns out they do, and they can go a long way in a night," said Dr Dave Hodgson, who led this study. The researchers say their new work indicates that snails pose a growing threat to pets. "They are not just lettuce munchers, they are carriers of parasites that can kill your dogs," said Dr Hodgson. A recent survey of veterinary surgeons indicated that the lungworm parasite was now endemic.
"It is becoming a real problem not just in the south of England, it is moving north to Scotland," said Dr Hodgson. "It is a national problem and we all have to pay attention to the interactions between dogs and snails," he said. In the new work, the scientists were surprised to see so many snails followed the slimy trails laid by others. Dr Hodgson says it is all about conserving energy. "We know that snails use about 40% of their energy budget producing slime. Given a chance, a snail will prefer to follow a trail that has been laid by another, it is a form of cheating like slipstreaming," he said.
As to what pet owners should do, the scientists suggested they should regularly check the nooks and crannies in their gardens for snails and try to reduce exposure to the species. "I wouldn't be too happy suggesting that there should be a snail apocalypse and everyone should get rid of them," said Dr Hodgson. "I think awareness is a better idea, people need to understand the wildlife in their gardens and that no organism is totally harmless."