Rats are nocturnal (active at night) and try to avoid people, so it is rare to see a rat out during the day. Unless you are inspecting your property at night, you may need to look just for signs of rats. If you are seeing rats out during the day, then it is likely that there is a large infestation in the area.
Burrow holes that are 1.5 to 3 inches in diameter alongside foundations, sheds, fences, or wood and brush piles
Droppings that are about 3/4” long with blunt, rounded ends
Rat trails in grass or tunnels under fences
Gnaw marks on surfaces or garden vegetables
Chew holes through trash cans or trash bags
Grease marks. Rats usually travel alongside walls or fences as protection. Their greasy fur can leave a black streak along these surfaces. Corners may be especially dark and greasy, as rats will hug corners as they travel.
Watch the behavior of your pets. Dogs may try to dig under sheds to get to rats and cats may stare intensely at a woodpile to wait for a rat to come out. Pets suddenly obsessed with getting into a cabinet or closet may indicate a rodent is in there.