The Common Pill Bug, or roly-poly, is not an insect but a terrestrial crustacean — the only crustacean fully adapted to life on land. When threatened it rolls into a perfect sphere, protected by its overlapping armored plates. It breathes through gills that must remain moist, making it dependent on humid microhabitats. It is introduced from Europe and now cosmopolitan.
Best time to see a Common Pill Bug
The best time to see a Common Pill Bug is March–June, when about 64% of U.S. sightings happen, based on 90,521 research-grade iNaturalist observations.
Not certain it is a Common Pill Bug? What bug is this? walks through what to check first and the lookalikes that catch people out.
Recent Common Pill Bug sightings near you
Live, research-grade observations from iNaturalist. Allow location to center the map on you.
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