What Noises Do Rats Make in Walls?

University of Missouri Extension names the specific noises associated with rat activity: gnawing, climbing in walls, squeaks, and fighting noises, concentrated during the periods rats are most active. Because rats are nocturnal, that activity — and the noise that comes with it — clusters after dusk and through the night, often from wall voids, the attic, or spaces behind cabinets.

The practical difference between a rat and a mouse in the wall largely comes down to size. Rats are considerably heavier than mice, so their gnawing tends to sound deeper and more forceful, and their movement can produce audible thumps as they climb or shift position — sounds a much lighter mouse simply can't generate. Mice, also nocturnal, tend to produce faster, lighter scratching and higher-pitched squeaks. This loudness comparison is a reasonable inference from the documented body-size difference; extension sources confirm the individual behaviors (gnawing, climbing, squeaking) and the nocturnal timing more directly than a formally measured volume study.

Because ears alone are an imperfect diagnostic, pair what you hear with visible evidence before deciding on a control approach: rat droppings are larger with blunt ends (roughly ½–¾ inch) versus a mouse's smaller, pointed pellets; gnaw marks and grease trails differ in scale; and rats generally need a larger entry gap (about ½ inch) than mice (about ¼ inch). Getting the species right matters because trap sizing, bait placement, and exclusion gap targets differ between the two.

Any repeated in-wall noise at night — regardless of species — points to active rodent presence and warrants the same sequence: identify which species you're likely dealing with using the signs above, set appropriately sized traps at wall lines and known travel routes, confirm the noise and any droppings have stopped for several days, and only then seal the entry point. Never seal while there's still activity, since a live rodent trapped inside a wall or attic will die there and decay for weeks.