Ash-black slug

If you go down to the woods tonight you might come face to face with one of the world’s largest land slugs! Most Ash-black slugs (Limax cinereoniger) are between 10 and 20cm long, but larger ones have been recorded. This nocturnal slug is only found in ancient woodlands. On damp nights the slugs emerge to feed on fungi, lichens and algae and can be found on the woodland floor, on stumps or up trees. During the day they hide under large pieces of dead wood. Adult Ash-black slugs can be found all year round. Ash-black slugs are one of the keeled slugs – they have a ridge or keel running along their back. The keel is pale in comparison to the dark grey body colour. Some Ash-black slugs have thick black and grey stripes along their bodies. If you turn an adult Ash-black slug over you will see that the underside of the foot is dark grey with a white stripe down the middle.

Fast Facts

Latin name: Limax cinereoniger

Notable feature: the UK’s largest slug, Ash-black slugs can grow to 25cm long! They have a keel down their back, and a white stripe down the middle of their foot.

Where in the UK: widespread, but only found locally on ancient woodland sites, thought to be declining.


Ancient woodland.

Did you know?

Slugs and snails belong to a class of invertebrates call the gastropods – meaning belly-foot!

Did you know?

In the past, slugs were sometimes used as a cure for warts.  An artifact in the Pitt Rivers Museum in Oxford consists of a glass jar containing a slug impaled on a thorn, the label on the jar gives the following instructions: Charm for Warts, Oxfordshire. Go out alone & find a large black slug. Secretly rub the underside on the warts and impale the slug on the thorn. As the slug dies the warts will go.

If you’d like to know more about slugs and snails visit the Conchological Societywebsite.