Actual Size: 5/8″

Characteristics: Technically classified as crustaceans. Pillbugs curl up, sowbugs do not.


  • Confined to areas of high moisture due to their innate severe water loss.
  • Found in mulch, under rocks, etc.
  • Sowbugs do not survive long indoors.

Sowbugs and pillbugs are found throughout the United States and because they are similar in appearance, their names are sometimes used interchangeably. Often known as roly polies, pillbugs are able to roll up into a tight ball when disturbed or threatened. However, the sowbug has a pair of tail-like appendages which project out from the rear of its body, preventing them from rolling up to protect themselves. They are easily recognized by their back, which is made up of a number of hard individual plates. Since sowbugs require moisture, they do not survive indoors for more than a few days unless there are very moist or damp conditions.

Sowbug Habitat

Sowbugs thrive in moist environments and can be found outdoors under mulch, fallen leaves, and rocks. Sowbugs are nocturnal and require humid conditions during the day. Sowbugs are scavengers and feed mainly on organic matter. They may leave their natural habitats at night, and crawl about over sidewalks, patios, and foundations. Sowbugs can become a nuisance as they often invade crawl spaces, damp basements and first floors of structures at ground level.

Sowbug Behaviors, Threats or Dangers

Sowbugs do not bite or sting and cannot damage household furnishings. Sowbugs are mainly a nuisance pest, especially when they venture indoors. They are harmless to people, but can damage the roots of plants when they eat. Sowbugs typically enter buildings through door thresholds, especially homes with sliding-glass doors on the ground level. Seeing a sowbug in the home usually means that there is a large population outdoors.

Sowbug Prevention

To keep sowbugs from entering your home, reduce moisture by using a dehumidifier, repair water leaks and run exhaust fans in bathrooms and attics. Ensure that basements and crawl spaces are well ventilated and free of clutter. Inspect the exterior of your home, sealing all cracks and crevices around doors, windows, spigots, and vents with silicone-based caulk. Store firewood up off the ground and at least 20 feet from home. Additionally, clean up leaf litter, lawn clippings, and other debris that sowbugs might use as hiding places.