The second spring pupation takes place in old stubs, and the adults emerge a short while later. Fresh droppings are dark in color and soft intexture. After three days, they harden and lose their dark color. Rats urinate in areas they frequent. Since urine gives off a fluorescent glow under ultraviolet light, a blacklight can be a useful tool for locating areas of rat contamination.
Rats keep indoor runways, or well-used paths, free of cobwebs, debris, and dust.
Norway rats' runways are usually well-defined paths at floor level next to walls and other vertical surfaces. Roof rats' runways are above on rafters, pipes, etc. Outside, roof and Norway rats' runways appear as narrow paths through vegetation. Rats make sounds when climbing, gnawing, clawing and moving. Footprints and tail drags can be seen in dusty locations.