Rat or mouse: why the question is far from idle
The answer determines bait placement, the number of bait points, and the timing.
"We have rodents" is not a sufficiently specific problem statement. Rats and mice behave so differently that tactics effective against one work poorly against the other.
The mouse is curious and readily investigates new objects. It samples bait almost immediately, but eats small amounts in different places, so many bait points are needed, positioned at close intervals — every two to three meters along the walls. A mouse rarely ventures far from its nest: if signs are found in a particular corner, the source is almost certainly nearby.
The rat behaves in the opposite way. It is cautious and wary of anything new in familiar surroundings — a trait known as neophobia. A rat may avoid a new bait station for several days, and this is a normal course of events, not a failure. However, it travels tens of meters along established routes beside walls, so fewer bait points are needed, but they must be placed directly on those routes.
In practical terms, the difference is this. With mice, no bait uptake after two days is a reason to reconsider placement. With rats, two days mean nothing yet; the situation should be assessed after a week.
The easiest way to determine which rodent you are dealing with is by its droppings: mouse droppings are the size of a grain of rice, while rat droppings are noticeably larger, up to a centimeter and a half. The second clue is the size of gnawed holes and the pattern of damage to packaging.
