While cleaning out our attic, we found several piles of what looks like mouse poop but I’m wondering if it’s bat poop instead. What does bat poop look like? E. G., Wellesley, MA

It’s true that bat poop (or droppings, or guano, or feces, or scat) looks very much like mouse poop. The droppings of both are black and about the same shape and size until you look more closely. And if you really want to tell them apart and are not squeamish, then crushing them will give you the answer.

The secret to the difference in the droppings lies in the diet of the animals. Bats feed almost exclusively on insects and shiny insect parts (wing and cuticle fragments) are seen in their droppings (see What Do Bats Feed On?). Because the droppings are undigested insect parts, they crumble easily into a powder, even when fresh.

You might find some insect parts in mouse droppings but insects are not the main part of their diet. Fresh mouse droppings are squishy and slimy when fresh and turn hard when old (see All About Mouse Poop!).

Another clue for you is that bat droppings are usually found in piles while mouse droppings are scattered but not generally in piles. The drawings and information here are for average, dry droppings from an average adult animal. Droppings will vary depending on the animal’s age, size, health, and diet. Examine groups of droppings, not just one or two, to get an idea of the average dropping.

House Bat Droppings Identification

• Length ¼ to ½ inch
• Blackish in color, even old droppings glisten
• Ends blunt, not pointed
• Fresh droppings break and crumble easily
• Shiny insect parts easily seen

House Mouse Droppings Identification

• 

  Mouse droppings, 1/8 to 1/4 inch long

  Length 1/8 to ¼ inch

• Blackish in color; old droppings dull, fresh droppings may glisten
• One or both ends pointed
• Fresh droppings are soft with putty-like texture
• Often contain rodent hairs

Attic Bat Removal Must Be Completed Soon!

You should give Colonial Pest a call for a professional inspection of your attic. Whether bats or mice, we offer control measures, including pest exclusion measures that will seal openings that the bats or mice are using to get inside. If you have bats, there is a narrow window of time to legally block them from your attic (see Signs That You Might Have Bats in Your Attic). In our area, bat removal generally must be done before the end of May (see Now is the Time to Block Bats From Your Home). We have nuisance wildlife specialists on staff who can handle the job for you. Give Colonial a call!

Credit: Techletter.