Why do slugs and snails produce a silver trail?

The characteristic slime trail left by slugs and snails has some of the qualities of both a glue and a lubricant. It helps the creature glide forwards when pressure is lifted, or stick to surfaces when pressure is applied. It’s made from a carbohydrate mucus and a ‘hygroscopic’ protein – meaning that it absorbs moisture from the air, helping to prevent it from evaporating. The slime is secreted from a gland inside its ‘foot’, and the chemicals it contains are also important for communication. Interestingly, the medical community is now investigating the adhesive and elastic properties of this slime, with the hope that it might lead to a synthetic glue that’s capable of repairing tissue damage.