Description: One of the garden slug group, but much smaller than the others and with points or prickles on the dorsal tubercles which earns it the popular name of hedgehog slug. Colour variable - may be banded or unbanded. 15-20 mm.

World Distribution: Found near coasts from southern Scandinavia to Portugal and the Azores. Distribution type: Oceanic Wide Temperate (61).

Irish Distribution: Common everywhere but particularly in the west.

Ecology:

• In grassland of all kinds and in a variety of woodland types
• Appears to avoid dry or excessively disturbed environments such as sand dunes and gardens (Boycott, 1934)
• Often found on peaty soils but not at high altitude

Key Identification Features:

• A small slug, easily the smallest and most compact (nearly bell-shaped at rest) of the garden slug group
• Very variable in colour, from unbanded pure white or orange to pale grey with thin lateral bands, or charcoal grey with black lateral bands (the latter is rare)
• Tubercles coming to points giving a 'prickly' appearance at rest (observe closely from the side when the tubercles appear to glisten around the minute points at their apexes)
• Sole yellow to orange
• Tentacles grey - compare the purplish tones in the tentacles of immature Arion owenii which can otherwise closely resemble mature A. intermedius in appearance

Red list status:

• Least concern (lc).

Distribution Map from NBN: Arion intermedius at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Arion intermedius at iNaturalist World Species Observations database.

GBIF data for Arion intermedius | Classification: Gastropoda, Stylommatophora, Arionidae, Arion

Thumbnails for genus Arion