Bat Bug

What it does

Bat bugs are blood-feeders that live near their bat hosts in roosts. When a bat colony leaves or is excluded, the hungry bugs disperse downward through wall voids and ceilings into living areas, where they bite people as a substitute host. They hide in cracks by day and emerge to feed.

Where it lives

Their true habitat is bat roosts in attics, chimneys, wall voids, and behind fascia. From there they move into bedrooms and living spaces along pipes, wiring, and gaps. They are found across the US wherever bats roost in buildings, and are most often noticed after a bat problem is disturbed.

How it breeds

Like bed bugs, females lay eggs in cracks near the roost; nymphs pass through several molts, each requiring a blood meal, developing over weeks in warm conditions. Their reproduction is tied to the presence of a bat host, and populations decline once the host and harborage are removed.

What it eats

Bat bugs feed on the blood of bats by preference. In the absence of bats they will bite humans and pets to feed. They do not eat household food or fabric.

Identification

Bat bugs are flat, oval, reddish-brown, and about 4-5 mm, essentially indistinguishable from bed bugs to the naked eye. The reliable difference is microscopic: bat bugs have longer fringe hairs on the pronotum (the shield behind the head). Correct ID often requires an entomologist or pest professional.

Signs of an infestation

• Bed-bug-like bites appearing, often after bat activity
• Small flat reddish-brown bugs on walls and ceilings
• Bugs concentrated near attic hatches, light fixtures, or chimneys
• History of bats roosting in the attic or walls
• Bugs found upstairs and along ceiling lines rather than only in beds

Prevention tips

• Have bats professionally and legally excluded from the structure
• Seal attic gaps, chimney openings, and wall penetrations after exclusion
• Screen vents, soffits, and louvers to prevent bat re-entry
• Install door sweeps and seal cracks between rooms and voids
• Inspect for and address bat guano and roost sites promptly

Professional solutions

Bat bugs are a two-part problem, so a professional approach is strongly recommended. A wildlife specialist removes and excludes the bats legally (timing matters for protected maternity seasons), then a pest professional treats harborage and voids with EPA-registered products. Treating bugs without removing the bat roost only leads to recurring bites.