Old droppings are grey, dusty, and will crumble. Fresh droppings are black, shiny, and puttylike. Rodents urinate while running, and the streaks are characteristic. The urine glows under ultraviolet lights and glows blue-white when fresh. Gnawed Objects - Rodents gnaw every day in order to keep their teeth short and sharp.
Rats also gnaw to gain entrance or to obtain food.
Teeth marks on food, building materials, wire, and edges of beams are indications of gnawing. They will gnaw holes in wooden walls, pressed wood, and posts. Fresh gnawing in wood is usually light-coloured with sharp, splintery edges. Old gnawing is smooth and darker. Runways - Rats habitually use the same paths or runways between harbourage and food or water.