The slug of the Baskervilles

Prowl the wilds of Dartmoor at night and you just might stumble upon our largest land slug

- Jack Watkins

SHORT of re-enacting a scene from The Hound of the Baskervilles, you might think there is little reason for prowling the wilds of Dartmoor at night. A naturalist wouldn’t find it so strange, however, given that some of the area’s most intriguing wildlife—including bats, owls and nightjars—is essentially nocturnal. Also among their number is the ash-black slug, as Dartmoor National Park is one of the strongholds of what is believed to be the world’s largest land slug. Africa may have its Big Five, which includes lions and rhinos, but the park’s website states that it is proud to include the ash-black as a member of ‘Dartmoor’s Little Five’, keeping company with the cuckoo, marsh fritillary, otter and blue ground beetle.

It’s possible that other giant slugs await discovery in the equatorial rainforests, but what is certain is that, among the 44 known species present in Britain, Limax cinereoniger is our largest—most measure between 4in–8in, but some clock in at a whopping 12in. A. E. Ellis’s British Snails, first published in 1926 and for 40 years the standard work on the subject, even described them as ‘being up to 10cm to 40cm [4in–15¾in] long’. By comparison, one of the most common slugs, the large black (Arion ater), reaches up to 5½in in maturity.