Rats will leave a hind foot track of about 3/4-1 inch where a mouse’s track measure’s 3/8 of an inch or less. Rats will also drag their tails, leaving a mark between their feet tracks. Unscented baby powder or flour, lightly sprinkled can help you determine tracks and their runways as they cross suspected areas.
Gnawing holes from rats are about 2 inches or more in diameter. They have rough edges and they prefer to gnaw on wood, but can also damage electrical wiring. Rat burrows can be found along foundations, or beneath rubbish and shrubbery. If the burrow is active it usually clear of vegetation. Rat runways are smooth and well packed. Indoors, these runways are free of dust and dirt.