Signs of an Infestation of Roof Rats Seeing a dead or alive roof rat is frequently the first sign of an infestation. Other signs can indicate the presence of roof rats. One thing to look for is the presence of rat droppings, in and around the premises. Droppings are 12 to 13 mm and have pointed ends. They may be soft and moist, if fresh, or hard and dried if older. Any sign of droppings indicates the presence of rodents, which warrants a visit from an exterminator even if it is a different type of rodent. Not sure if you have roof rats? Flick can conduct and inspection determine whether you have rodents present, and, treat your home for rats and other common household pests.