Rat vs mouse droppings: how to tell and clean up safely

How can you tell rat droppings from mouse droppings?

Size is the main clue. Mouse droppings are small, thin and pointed at both ends, a bit like a grain of rice or smaller. A mouse leaves lots of them, scattered along the paths it travels. Rat droppings are chunkier, and a rat leaves fewer of them, often in a small pile or along a run.

In Brisbane the rat you're most likely to have in the ceiling is the black rat, also called the roof rat (Rattus rattus). Its droppings are spindle-shaped with pointed ends. Norway rats, more likely near drains and bins at ground level, leave larger, blunter capsules.

Droppings can also come from other animals. Possum droppings in a roof are larger and more pellet-like, and possums are protected in Queensland. If you're not sure what's up there, get it identified before anything is baited.

How old are the droppings?

Fresh droppings are dark, moist and soft-looking, sometimes a little shiny. Old ones turn grey, dry and crumbly. If you clear a spot and fresh droppings show up again in a day or two, the animal is still active.

That's a handy trick before you call anyone. Clean one small area and check it the next night. Fresh droppings, gnaw marks on packaging, greasy smears along walls and scratching at night all point to an active problem.

How to clean up droppings safely

Rodent droppings and urine can carry bacteria, so the aim is to avoid stirring up dust and to avoid touching them with bare hands. This is in line with general public health advice, and Queensland Health has information on rodent-borne illness if you want to read more.

1. Open doors and windows and let the area air out for a while before you start.
2. Put on disposable gloves. Keep pets and children out of the area.
3. Don't sweep them and don't vacuum them. Both can throw fine particles into the air.
4. Spray the droppings and the surface around them with a household disinfectant until they're wet through, and leave it for the time on the label.
5. Wipe up with paper towel, put it in a plastic bag, seal it and place it in the outside bin.
6. Wash the surface again with hot water and detergent, then disinfect food surfaces.
7. Take off the gloves, bag them, and wash your hands with soap and water.

For a lot of droppings, or anything in a roof void, don't go in yourself. Bruin's technicians don't enter roof voids, so ask a professional cleaner or an appropriate tradesperson to handle heavy contamination, and treat the rodent problem separately.

Are rat droppings dangerous?

They can be. Rodents can carry germs that make people sick, and they can contaminate food, benchtops and utensils with droppings, urine and saliva. One disease linked to rat urine is leptospirosis. It's spread when urine from an infected animal gets into cuts or into the eyes, nose or mouth.

We're pest controllers, not doctors, so keep it general. Handle droppings as you'd handle any contamination, wash your hands, and see your GP if you become unwell after clearing them out. Queensland Health has a leptospirosis fact sheet with the symptoms and who's most at risk.

Found droppings. What now?

Cleaning up is only half the job. Droppings mean rodents are getting in, and they'll be back unless the entry points are found and the animals are dealt with. Rats fit through a gap about the width of your thumb, and mice through something much smaller.

Look for gaps around pipes, under doors, at the edge of the roof and eaves, and around cabling. Store food in sealed containers and keep bins closed. If the signs persist, call. Our rodent control is quoted after an inspection, and the technician will confirm what you have, find the way in and place bait safely, away from children and pets. If you hear scratching overhead, read our guide on what to do if you hear rats in the roof.