Why Are There Pillbugs in My House?

What Is That Bug in the Corner That Rolls into a Ball?

That is a pillbug, also known as a roly-poly. Its most distinctive trick is curling up into a tight little ball when startled — that is its signature defense move.

What Do Pillbugs Look Like?

• Gray-brown or gray-black body, segmented like tiny armor plating
• Seven pairs of legs (14 total). They are crustaceans, not insects.
• About 1–2 cm long
• Flip one over and the underside is flat
• When curled up, it is round like a little pill (which is how they got the name "pillbug")

Pillbugs vs. Sowbugs

• Pillbugs (roly-polies): Can roll into a complete ball. Body is more rounded.
• Sowbugs: Cannot roll into a complete ball. Body is flatter. They run faster.
• Control methods are the same for both.

Where Do Pillbugs Show Up?

• Bathroom corners and around floor drains — plenty of water, high humidity
• Near kitchen drain pipes — damp with food debris
• Under flower pots and in saucers — constantly moist after watering
• Outdoors along foundation walls, in leaf litter, and under bricks — they hide in these spots during the day and come out at night
• Basements and semi-basements — perpetually damp, ideal habitat

Are Pillbugs Harmful to People?

Pillbugs are completely harmless to humans — they do not bite, do not feed on blood, do not spread disease, and do not damage furniture. Their only "harm" is being creepy to look at. Seeing pillbugs in your home means the environment is damp, but the bugs themselves are nothing to fear.

Why Are They Called Pillbugs?

They need high humidity to survive — their bodies are poor at retaining moisture, and a dry environment will cause them to dehydrate and die. Finding pillbugs in your home means some corner is too damp.