Rat or mouse droppings? How to tell

How big are rat and mouse droppings?

Size is the quickest test. A rat dropping is several times longer than a mouse dropping, and much thicker.

	Rat	Mouse
Length	About 20mm (3/4 inch)	3 to 6mm
Shape	Spindle-shaped, thick, like a raisin or baked bean	Thin and rod-shaped, like a grain of rice
Colour	Dark, though colour varies	Usually black
How many	Up to 40 in a night	About 80 a day
How they are spread	In groups, where rats travel again and again	Scattered, in large numbers
Where you find them	Along regular routes, by walls, under sheds and near food	Under kitchen sinks, around boilers, in roof spaces and near food

What else helps you tell them apart?

Look at how widely the droppings are spread. Mice stay within about 1.5 to 5 metres of home. Rats range over 50 to 100 metres, so their droppings follow longer routes.

Check whether they are fresh. Fresh droppings are soft and moist. Older ones dry out and harden. Clear an area, then look again over the next few days.

Look for other signs nearby. Rats leave greasy smear marks along their routes and dig burrows outdoors. Mice leave nests of shredded paper, cloth or wool in lofts, airing cupboards and under floors.

In a loft, droppings could also belong to squirrels or glis glis. Our guide to noises in the loft covers the differences.

What do droppings in different places tell you?

• Kitchen cupboards, under the sink or round the boiler. Small, scattered droppings here are classic signs of mice.
• Along skirting boards or behind appliances. Check the size. A line of large droppings along a wall suggests a rat route.
• Shed, garage or compost bin. Large droppings in groups point to rats, especially near burrows.
• Loft. Mice, rats, squirrels and glis glis all use lofts, so size and the time you hear noise both matter.

If you spot the animal, do not mistake a young rat for a mouse. At six weeks a young rat weighs about 100g, far more than an adult mouse at about 15g. Young rats also have large heads and feet.

Are rat and mouse droppings dangerous?

They can be. UKHSA says rodents can pass infections to people through urine, droppings and saliva. It names leptospirosis and hantavirus among them.

Its advice is that all rodents should be presumed to carry infection. Breathing in dust from dried droppings and urine is one of the routes it warns about. Read more in are rats dangerous?

How do you clean up droppings safely?

UKHSA’s cleaning advice is written for pet rodents. Because it says all rodents should be treated as carrying infection, the same steps make sense for wild droppings.

1. Open windows and let the space air before you start.
2. Wear rubber household gloves. For a large amount, such as in a loft, add an FFP1 or FFP2 dust mask.
3. Do not sweep or vacuum. Both put particles into the air.
4. Dampen the droppings well with water, then add disinfectant. Leave it for at least 5 minutes.
5. Pick them up with a wet wipe or damp paper towel. Seal everything in a plastic bag and put it in the bin.
6. Disinfect the surface again. Wipe food areas with an anti-bacterial cleaner.
7. Take off your gloves and wash your hands well with soap and water.

If you find a lot of droppings, or droppings in hard-to-reach places like under floors, the source is still there. Cleaning alone will not fix it.

When should you call someone?

Call if fresh droppings come back after you clean, or if you find rat droppings indoors. We treat rats from £149 and mice from £139, including VAT. Both cover 2 visits.

We call back within 30 minutes, Monday to Saturday, 8am to 6pm. We agree a fixed price on the phone, and visits are usually [same or next day].