Scientists are worried that the fast-moving snails are spreading a parasite that is deadly for dogs.
Over the past few years the wet summers enjoyed across the UK have proved the ideal breeding grounds for snails.
“They are not just lettuce munchers, they are carriers of parasites that can kill your dogs”
Dr Dave Hodgson University of Exeter
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, multicoloured 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 across the UK
“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 and was also involved in a BBC amateur science experiment in 2010 that sought to discover if snails had a homing instinct.