Quick facts
Common name(s): pill woodlouse, roly poly
Scientific name: Armadillidium vulgare
Family: Armadillidiidae
Habitat: woodland, grassland, urban areas
Predators: birds and small mammals
Origin: native
Pill woodlouse (Armadillidium vulgare)
Easily found and easily startled, the pill woodlouse is named after its habit of rolling tight into a ball when disturbed. They’re a common sight in woodland, parks and gardens alike.
What do pill woodlice look like?
Adults: can grow up to 18mm long and are usually slate grey. Their exoskeletons have several segments, or plates. The pill woodlouse is more rounded than the common woodlouse.
Young: look like a smaller, white versions of adults and are carried in a pouch under the mother’s abdomen.
What do pill woodlice eat?
Pill woodlice feed on dead plant matter, as well as lichen and algae. They find food using their senses of taste and smell.
Credit: Custom Life Science Images / Alamy Stock Photo
How do pill woodlice breed?
Females develop a brood pouch during the breeding season. When fertilised, the eggs pass into it and hatch, developing in the pouch until the young are ready to emerge.
Where to find pill woodlice
The pill woodlouse is common and widespread throughout the UK, but is more frequent in the south and east.
Signs and spotting tips
You can spot pill woodlice throughout the year, though they may be less active in cold weather. Look for them on the soggy ground under stumps of wood or plant pots.
Did you know?
In the US, children sometimes keep pill woodlice, or pill bugs as they are known there, as pets.
Threats and conservation
This species is common and not believed to be under threat.