This is one of the most common early complaints.
People hear movement after dark, usually in a wall, ceiling, loft, or under the floor, and immediately assume it must be rats. Sometimes they are right. Sometimes it is mice. Sometimes it is even squirrels.
BPCA says rats may be heard scratching, gnawing, and scuttling around, and it also says those sounds can sometimes be confused with squirrel activity. BPCA’s mouse guidance adds that mice are nocturnal and are often heard running about at night while searching for food.
Rodents are often more noticeable after dark because that is when they are active and the building is quieter.
BPCA specifically describes mice as nocturnal, and its rat guidance also frames sounds such as scratching, gnawing, and scuttling as typical clues people notice around hidden spaces.
So the timing is part of the clue.
Not proof by itself, but still part of the pattern.
If the noise is coming from walls, lofts, ceiling voids, or under floors, common possibilities include:
BPCA links rats with scratching, gnawing, scuttling, smear-marked routes, and nesting in roof spaces, wall cavities, and under floors. It links mice with nesting in roof spaces, under floors, wall cavities, and hidden indoor voids, and notes they are often heard at night.
This is the bit people do not always want to hear.
The sound tells you something may be there. It does not always tell you what it is. BPCA says correct identification is important because similar noises can come from different pests, including squirrels.
That is why it helps to look for other signs at the same time.
If you are hearing movement at night, also look for:
BPCA’s rat and mouse guidance, along with BPCA-hosted 2026 rodent advice, all point to these as the clues that make identification more reliable than sound alone.
Location gives useful context.
Noise in a loft or wall cavity could point to rats, mice, or squirrels. Noise under floors or behind kitchen units can lean more strongly toward rats or mice. BPCA says brown rats commonly live in roof spaces, wall cavities, or under floorboards, while mice commonly nest in roof spaces, wall cavities, under floors, basements, and storage areas.
So the location does not solve it by itself, but it helps narrow things down.
It becomes harder to ignore when:
BPCA-hosted 2026 advice specifically flags scratching noises at night, droppings, smear marks, odour, and shredded nesting materials as early signs of infestation.
That is the point where it stops sounding like a random one-off.
If you are hearing scratching noises in the walls at night, the smartest move is usually not to guess the species from the sound alone.
Listen to the pattern, check for the usual signs nearby, and treat the noise as part of a wider picture rather than the whole answer. If the signs keep adding up, Pest Gone can help you work out whether it looks more like mice, rats, or another pest altogether.
