Mice and rats are the most common rodents found in the home. The telltale signs that you are sharing your living quarters with a rodent, or litter of rodents, include nests, which are often located in warm areas; gnaw marks; tracks; holes and marks on food packages; and droppings — typically the most prolific sign. While you are unlikely to spot the culprits directly due to the fact that mice and rats are generally nocturnal, an easy way to discover the type of rodents in your home is by identifying their droppings.
Examine the rodent droppings you have discovered. Mice, as the smallest rodent, leave behind many tiny droppings that are rod-shaped and roughly the size of a grain of rice. The ends of mouse droppings are also pointed. The droppings are typically found in areas where food is stored, such as cabinets, drawers, cupboards and pantries.
Use plastic gloves to crush a piece of dropping. Mouse droppings are often confused with those left by bats. An easy way to tell the difference: Bat droppings can be crushed into small, dry pieces, but mouse droppings cannot.
Identify rat droppings in a similar fashion. Roof rats are larger than mice and leave larger droppings, which are roughly a quarter inch long and shaped like spindles. These droppings are also pointed at each end. Norway rats are larger than roof rats and leave droppings that are a quarter to a half inch long and that are shiny, black and crescent shaped.
Distinguish raccoon droppings by size and location. While not technically a rodent, raccoons have the tendency to invade the home similarly to the way that mice and rats do — in warm, secluded areas such as attics. Unlike mice and rats, raccoons choose one particular spot as their toilet. Raccoon droppings are roughly two or three inches long and look similar to those left by a dog.