Steve Downer / Juvenile Common frog (Rana temporaria) on back of a Common snail (Cornu aspersum), UK, June.

Steve Downer / Juvenile Common frog (Rana temporaria) on back of a Common snail (Cornu aspersum), UK, June.

Brian Bevan / Two Giant african snails (Achatina fulica) emerging from their shells and looking around, UK. Captive.

Steve Downer / Close up of a Black slug (Arion ater agg.) feeding on a Plantain lily (Hosta) leaf, Birmingham, England, UK, August.

Steve Downer / Black slug (Arion ater agg.) feeding on a dead Yellow slug (Limax flavus), Birmingham, England, UK, August.

Steve Downer / Grove snail / brown lipped snail (Cepaea nemoralis) with juvenile riding on its back, Birmingham UK June.

Steve Downer / Yellow slug (Limax flavus) back lit embryo moving around in egg case.

Steve Downer / Yellow slug (Limax maximus) moving across bridge over road with traffic in the background. Birmingham, UK. June.

Steve Downer / Black arion slug (Arion ater) moving, viewed from beneath showing ripples or pedal waves used for locomotion.

Steve Downer / Yellow slug larva (Limax flavus) emerging from an egg case, controlled conditions.

Steve Downer / Yellow slug larva (Limax flavus) emerging from an egg case, controlled conditions.

Steve Downer / Banded snail (Cepaea nemoralis) on rear of a backlit rose leaf, controlled conditions.