Reviewed by William "Willy" Vizcarrondo, NYS DEC Certified Commercial Pesticide Applicator C1825832. Updated September 23, 2026.
Short answer
Usually mice. Light, quick scratching and skittering inside a wall or ceiling after dark, especially in fall, is house mice moving between the nest and food. Heavier, slower scratching or gnawing at night is rats; scampering at dawn and dusk is squirrels; and loud thumping and dragging at night in the attic is a raccoon.
The time of day and the weight of the sound sort it out. Mice are nocturnal, light and fast: a faint scratching or scurrying in the wall behind the bed or in the ceiling over the kitchen, starting an hour or two after the house goes quiet, and sometimes a soft gnawing. UC IPM lists sounds at night among the standard signs of house mice, along with droppings, fresh gnaw marks and a musky odor. Rats sound heavier and slower, with distinct gnawing, and Norway rats tend to be low in the house, in the basement or crawlspace walls. Squirrels are the opposite: active in daylight, loudest at dawn and just before dusk, running and rolling nuts in the attic. Raccoons are the heaviest thing you'll hear, thumping, dragging and sometimes chattering, at night, almost always in the attic or a roof corner.
Because the wall is the highway. House mice travel inside wall voids, along pipes and wires and through the gaps where they pass between floors, and they nest in insulation, behind cabinets and in the ceiling below a bathroom. UC IPM notes they seldom go more than 30 feet from the nest to food, so a wall you hear them in is within 30 feet of both. Older Long Island houses with balloon framing, chases for old pipes and gaps at the sill give them a full network; the scratching moves from room to room because the mouse is following it.
Confirm it, then trap and seal. Look for rice-sized droppings under the sink, along baseboards and in the cabinet under the wall you hear them in, and for gnaw marks on food boxes. UC IPM's trapping guidance is to set traps behind objects, in dark corners and where there's activity, no more than about 10 feet apart. Then find the entry point: the gap under the garage door, the hole where the gas line comes in, the dryer vent, and seal it with steel wool and caulk or hardware cloth. If the sounds are heavy, in the attic, or in daylight, it isn't mice, and the fix is wildlife exclusion, not traps.
The calls start the same week every year, when the first nights drop into the 40s in October and the scratching starts in the ceiling over the kitchen in a Levittown cape or the wall behind the headboard in a Valley Stream Tudor. In the wooded North Shore towns, Huntington, Dix Hills, Stony Brook, the sound in the ceiling in daylight is more often a squirrel that came in through a chewed fascia board, and in the fall a raccoon looking for a den in the attic.
Related
Mice, if it's light and fast; rats, if it's heavier, slower and includes distinct gnawing. Rat droppings are raisin-sized with blunt ends, mouse droppings are rice-sized with pointed ends, and rats leave greasy rub marks along walls and beams. Norway rats also stay low, in basements and crawlspaces, while mice go anywhere.
Because mice, rats and raccoons are nocturnal and the house is quiet. They move when it's dark and still, and you notice the sound because everything else has stopped. Daytime scratching or running, especially around dawn and dusk, points to squirrels, which sleep at night.
Yes, and they do. The wall is how they travel, not where they stay. Mice come out into kitchens, pantries, closets and bathrooms at night to feed and drink, then go back into the void. Droppings in a cabinet or along a baseboard are the proof they're coming out.
Still not sure? Call (516) 509-6001 and we'll tell you what you're dealing with.