Roof Rat: Facts, Identification & Control
Black or brown, can be over 40 cm long, with a long tail, large ears and eyes, and a pointed nose. Body is smaller and sleeker than the Norway rat’s. Fur is smooth.
Behavior, Diet & Habits
Nests inside and under buildings, or in piles of rubbish or wood. Excellent climber that can often be found in the upper parts of structures.
Omnivorous, but shows a preference for grains, fruits, nuts and vegetables.
Becomes sexually mature between two and five months, producing four to six litters per year that consist of six to eight young each. Lives up to one year.
Roof rats are prodigious breeders. Females can breed year-round. Within a year, one female may be responsible for up to 40 new rodents.
Signs of Roof Rat Infestation
Visual sightings of live or dead rodents indicate rodent activity. If roof rats are seen exposed, it often indicates their hiding spaces are all filled by other rats or that they have been disturbed, such as by construction. Droppings are another good indicator of roof rat activity. Roof rat droppings are 12 to 13 mm with pointed ends, whereas Norway rat droppings are 18 to 20 mm and capsule shaped. Other indicators can include grease marks along surfaces as well as nests. Grease marks are produced as the rodent travels along an edge, and the oils in their fur are deposited. Indoor nests usually are constructed in insulation such as in attics.
Black rats have long been named as carriers of the fleas responsible for the Black Death in the Middle Ages. While this plague is no longer as serious a threat to humans, roof rats are still potential carriers of disease.
The first step in controlling a roof rat infestation is to properly identify the rodents. Roof rats have hairless, scaly tails that are longer than their heads and bodies. These rats are nocturnal and are excellent climbers.
To prevent a colony from nesting in your home, make sure that all the windows and vents are screened. Roof rats can also enter openings in walls, eaves and roof from the branches of trees. Trim all tree branches to further prevent entry.