Pest Poop 101

It may sound funny but your average bug man who’s been around for any length of time has probably taken a course on poop. Let’s face it, sometimes it may be the only evidence left behind (no pun intended) from which to identify your pest problem and thereby go about the business of solving it. I’ve had hundreds of clients over the years who purchased mouse bait, glue boards, traps and the like because they found small black fecal droppings on there counter tops. After about a week with no rodent but plenty more droppings they called me in and within minutes I let them know they need a roach job, not a mouse call.
For this article we’ll just handle just the most common id problems but if you need to verify something not listed please use the Ask the Bug Doctor page where you can also upload a picture and I’ll be happy to help.

Mouse verses roach

Mouse droppings are confused for roach droppings and vice versa quite a bit. Of course not all roaches produce big enough fecal matter to be compared and if it is hanging or smeared on a vertical wall you can pretty much rule out mice. Roaches such as the American, Australian or Oriental usually are the prime suspects if you have large roach droppings. Mice produce a lot of droppings, some say as many as 150 permouse poop vs. roach poop day while roaches do not so that is one of our first clues. However, roaches do tend to live in quasi nests and the pellets can add up giving you the illusion of having a mouse so don’t let this be your only rule. Mice poop just about where ever they run, on top of the refrigerator, in your strainer or drawers you name it. If they hang out in a place for a length of time or frequent a spot often the droppings may build up. Roaches tend to deposit their fecal matter near or in there nesting site. For a roach the odor is like a homing beacon so they can return to their favorable spot each evening when the nightly raid is done. Again this is a general tendency so keep that in mind. If you want to be 100% sure the best way is to take a close look at what your invader has left behind. Mouse droppings will almost always be somewhat tear dropped shaped. Round at one end and pointed at the other while a roaches dropping will be for the most part chunk like and almost square-ish. If you have a magnifying glass you may also see ridges in the roach dropping and you will never see that from a mouse. Any colored fecal matter such as green or red will most certainly be from a mouse and indicates they have eaten your green colored D-con where as a roaches poo is never anything but black regardless. Ok, if you’re still with me and not grossed out enough yet let’s look at the other most common misidentified pest poop.

Frog verses rat verses snake verses lizard

Norway vs roof rat pestcemetery.comRat fecal matter is very similar to mice. The exceptions are of course the size and the amount produced. Just as there are different kinds of mice there are also different rats. The 2 most common are the Norway and the Roof rat with the Norway excrement being the larger of the two. Rat droppings will often have a hair or two in them as well but look for all intensive purposes like a mouse’s only bigger. Frog poo is often mistaken for rats. It varies a bit as for some species as the texture is much softer and may take different shapes when it comes out or dries. Frog doo is usually much larger however and very delicate when set. If you poke the dropping it will usually flake or crumble apart quite easily. Also if you look closely you may see insect parts in the matter and sometimes small plant debris that may look something like a hair. I’m not exactly sure how often a frog goes and while it’s seldom inside a structure a lot of people will be fooled in to thinking they have a hoard of rats living just outside the door when it is really lizard or snake dropping pestcemetery.comjust some frogs living in their soffits. Now for the last dung example and none to soon, I’m running out of poop words. Snake & lizard doo doo is very often confused for both rat and frog but there is one quick way you can always tell the difference. These two critters dropping almost always have a white tip. The reason for the color is that they both incorporate urine with the bowel movement and that produces the white colored end. Now that’s about as far as my knowledge goes on the snake and lizard poop but if you’re in Iowa reading this I think you can rule out lizard if you see this. That is unless Hiawatha was somehow infested with them and they learned to survive the winters since I was a little boy.

Well, no certificate comes with the study but hopefully you’ve learned a little bit about the #2 world of a few common pests. I didn’t think I could write so much on this subject but apparently I paid attention to my poop class after all. I may just have to take back what I thought about the instructor as I sat through 2 hours of fecal matter training. “Man this guy is FULL of it.”

About The Bug Doctor

Jerry Schappert is a certified pest control operator and Associate Certified Entomologist with over two and a half decades of experience from birds to termites and everything in between. He started as a route technician and worked his way up to commercial/national accounts representative. Always learning in his craft he is familiar with rural pest services and big city control techniques. Jerry has owned and operated a successful pest control company since 1993 in Ocala,Florida. While his knowledge and practical application has benefitted his community Jerry wanted to impart his wisdom on a broader scale to help many more. was born from that idea in 2007 and has been well received. It is the goal of this site to inform you with his keen insights and safely guide you through your pest control treatment needs.

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  • Looks like classic roach poo…

  • Tear drop shape is almost always mice–chunky-squarish is most likely roaches.

  • Cool, glad to help

  • Curtis Williams

    I have what looks like bird droppings inside my garage on the wall. I keep my garage closed. What else could it be. It’s on both sides of the garage door. It’s a lot

  • Frogs often make a mess a the sides of walls. Perhaps it’s that.

  • Pretty small for a rat so I’d rule that out but also lacks tear drop shape to say mouse for sure. I’d place a sticky trap or two in the area (safely) and see what you get. My guess is a roach from the pics…

  • Hola

    I will put a sticky trap. Thank you!

  • Jennifer Gilbert Kempke

    I have been finding these droppings on my window ledge and in my garage. Can you help me identify them. I know I have a lizard and 2 frogs that hang out in my flower bed but am not sure whose leaving me these little “treats!”

  • Help

    Hello. My house have two bathooms but I use only one of them. The bathroom that I don’t use have this droppings under the faucet, no matter how many times I clean that bathroom, these droppings still appear.

  • I blew the pic up as much as I could–from what I see you may have a mouse.

  • With no size reference it’s tough to say. Lizard poo and rodent are quite similar. My guess is lizard because rats usually don’t defecate all in one area like this.

  • Let us know how it goes

  • Jennifer Gilbert Kempke

    I found this to be my problem. I have given him decon, a glue trap(he refused to go into) so tonight I have 2 traps set. One with peanut butter and one with cheese. The next thing I try will be a BB gun or perhaps a swing of the shovel! Super mouse just sits back and giggles at me!! Grr! Thank you for your reply!

  • CCM

    OK, so I find this in the middle of my basement carpet today. It’s long, dry and rather hard. It didn’t break when I pulled it off the rug. It was not there 2 days ago. Any educated guesses appreciated.

  • Gabriela Mascorro

    I keep finding these droppings on my garage walls, mainly by the garage door. I’m concerned that they might be rat droppings…eww
    Couldn’t post picture but they look like mouse poop…but bigger and has a white dot.

  • Gabriela Mascorro


  • The white indicates frog or lizard . It’s their urine.

  • Dried up worm I’d say

  • Nice pic!! To bad the camera didn’t come with a laser to shoot and kill the sucker. Cardboard boxes like a shoe box will often entice a mouse. Cut a hole on either end big enough for him and set your snap trap in there.

  • MI

    I found several of these on my garage floor recently. These are the size of a rice grain. These were not just on the corners but also under flat objects like card boards, heavy bags etc. So a mouse does no seem likely because it just can’t crawl under such tight spots. Could these be some kind of worm droppings or eggs. Not sure how clear the photo is but these are bright brown in color and have a circular rings through the length.

  • Hola

    I found a roach 🙁 at least isn’t a mouse. But I found rats outside my house. We have cats in the neighborhood and they don’t seem interested in the rats.

  • EJ

    I think I have a roach or mouse problem, blackly sticky substance all lining the inside corners of bathroom and kitchen cabinets but they are different shapes and sizes can you advise?

  • EJ

    Help what could this be?

  • I think I’d need a pic–sorry, your description could be one of a hundred things.

  • Most likely a pupal case of some insect. Really couldn’t say what until it hatched.. some sort of fly or gnat is my guess.

  • NM

    Any idea what could have left this behind? It’s located on top of fiberglass insulation that is behind the basement walls. I was inspecting for a ant nest by pushing down the insulation and found this pile. The pile is approximately 2″ across and there is another pile about half this size. It looks similar to raccoon feces but this space is too small for a raccoon to fit into. I’m located in Indiana and I cannot figure out what could have left this behind.

  • nm


  • It does look like coon to me as well. Or something of similar size–How it got there is a mystery but I’ve seen them in some pretty tight spots.

  • ruben

    I had these in my garage this evening. My question is, could their be mutiple of these in the garage in a matter of a few days. Meaning there were about 30 of these in about 3 different spots in about a quarter of the area of my 2 car garage.

  • Yes–but- mice, roaches, rats etc. all are pretty small, so that means their intestines are also small. This means a lot of little critters have to ‘go’ more often than larger things. So don’t always take the number of droppings as your sole clue.

  • ruben

    I thinkni mean more so that if they are pupal cases. They were more redish brown in shape versus the darker color that I have seen with mice.

  • Guest

    Found a few of these in a box in my storage unit. Having a tough time determining if this is roach or mouse. Any help is appreciated, thanks.

  • Guest

    Found a few of these in my storage unit. I can’t tell if it is mouse or roach.

  • From the pic I can’t really say 100% either..leaning toward a mouse as it almost looks like a hair on the end.. Try a sticky trap or two in the unit and hopefully you’ll know pretty quickly.

  • Rachael

    Any ideas on what these might have come from? I found them on my kitchen countertops and on the floor near the baseboards. Not too many, maybe about ten or fifteen scattered around in total, and so far as I can tell, only in the kitchen. There’re tiny. There was also a slimy brown spot on my counter, so at first I thought it was slug-related…but I have no clue.

  • Sorry but the pic gets blurry as I enlarge it and I could use a size reference… Is the brown spot near these droppings?

  • Rachael

    Sorry about the photo. Yes, the brown spot was on the counter. These are each about the size of a small peppercorn. After I posted this, I didn’t see anymore until after using my oven today. Two hours later I came back into the kitchen, turned the light on, and found two more on the stove. I have no food sitting out and am very clean.

  • I hesitate because it could be a roach but if it’s in the same place each time my mind thinks maybe something like drywood termites..The way to know for sure is to see 6 concave indentions around the pellet which the pic was not clear enough to determine.

  • Ratcats

    I used a Have-A-Heart trap. Catch them live and have my friend relocate them far far away. Extra crunchy peanut butter is good bait.

  • Andrew

    Found this on a kitchen cabinet door, and several more over the past week on our walls. From your description, it looks to be a roach “smear” – I always thought roach droppings were very small and round. Location: hot and humid Florida.

  • Andrew


  • Sorry- I don’t see the pic.. You can send one via my link;

  • Gini

    Hello, I just found something similar in the house today, did you discover the “beast” doing that? 🙂 Thank you!

  • Gini

    I forgot to mention that it left a yellow mark on the tiles, if that helps…

  • I’ve had worms on cellar floors that ‘semi’ dried similar to what you’re describing .

  • Jay

    Hi Jerry,

    I think I might have bed bugs. I did observe what resembled a bed bug quite a while ago. However, the only sign of fecal matter is a few dark specks on one mattress corner (below). Haven’t been able to see a bug since but have been finding these thin, dried, yellowish/white, broken strands on the box spring and around the bed (see below: encased in tape and a few were caught on double-sided tape I stuck to the bed in hopes of catching something). These don’t resemble bed bug feces according to what I’ve read. Do you have any idea what these might be? Thanks.

  • Jay

    Pictures didn’t go thru …. re-sending:

  • Jay


  • Jay

    re-send pic

  • Send the pics via my ask the bug doctor tab at the top of the page–I’ll re post it for you