Entity scope
This page uses the household common-name group ‘sowbugs,’ centered on terrestrial isopods that do not close into a tight ball. Species and family boundaries vary.
Quick identity
- Taxonomic context
- Terrestrial isopods, commonly including Oniscidae
- Entity scope
- A household common-name group
- Body
- Flattened oval body with overlapping plates
- Legs
- Seven pairs of walking legs
- Rear
- Uropods commonly project beyond the body
- Rolling
- Does not close into the tight ball typical of pillbugs
Key characteristics
- Sowbugs are terrestrial crustaceans rather than insects.
- The body is flatter than a typical pillbug and rear uropods are often visible.
- They may curve when disturbed but do not seal into a tight ball.
- Species-level identification usually requires more detail than a household image.
Where it is found
- Moist leaf litter, mulch, under logs, stones, pots, and decaying vegetation.
- Basements and ground-level rooms after movement through cracks or doors.
- Repeated live individuals indoors can point to excess moisture.
Behavior and activity
- Slow-moving decomposers that require damp conditions.
- May enter buildings after heavy rain or seasonal changes.
- Usually dies in ordinary dry indoor conditions.
Diet and resources
- Decaying plant material and associated organic matter.
- Moisture is essential for survival.
Common lookalikes
Why it matters
A moisture clue, not a structural pest
Sowbugs do not bite, sting, infest food, or damage structures. Their indoor presence is usually temporary and associated with damp entry conditions.
- Keep the distinction from pillbugs concise rather than duplicating a comparison Guide.
- Do not infer a hidden infestation from one outdoor wanderer.
Management direction
- Confirm the plated terrestrial-isopod form and projecting rear appendages.
- Reduce excess moisture and nearby decaying debris where practical.
- Seal ground-level gaps if repeated entry continues.
Have a pest photo to check?
Start a new photo identification. This Profile gives comparison context; it does not transfer certainty or diagnose your image.
Identify a photoReviewed guidance and sources
Last reviewed August 2026. Sources support the claims listed with them; their limits remain part of the review.
- University of Minnesota Extension — Sowbugs, millipedes and centipedes
Supports: Broad morphology, moisture associations, indoor entry, and proportionate risk context.
Does not support: Exact species identification or a universal indoor survival period.
Scope note: North American household and structural-pest context; local conditions vary.
- GBIF — Oniscidae
Supports: Taxonomic context for a major sowbug family.
Does not support: That every household sowbug belongs to one family or shares one appearance.
Scope note: North American household and structural-pest context; local conditions vary.