The roof rat is the smaller of the two most common types of rats; the common Norway rat is larger. Roof rats are also known as ship and black rats. The roof rat earned its name because it tends to live in the attics and rafters of buildings. Once roof rats become established, they damage the building's structure by gnawing through it. Likewise, they also contaminate food, causing the spread of dangerous diseases.
While Roof rats likely originated in Southeast Asia, they are now common all over the world, especially in tropical areas. In the U.S., roof rats are commonly found in the coastal states and the southern regions of the country.
These rodents have long, thin bodies and a long scaly tail. They also have a pointed nose with large eyes and ears. A roof rat's brown and black fur is soft and smooth, with a white, gray or back underside.
Adult roof rats have a body length of 6-8”. Their tails are longer, typically measuring 7-10”, for a total length of 16-17”. They typically weigh in at 5-9 ounces, but larger roof rats can weigh up to 12 ounces.
There are many indications there are roof rats in the home. First, seeing a rodent, either alive or dead, is proof of a rat infestation. A very common sign of rats is finding droppings, especially in the kitchen. Roof rat droppings are usually ½” in length with pointed ends. Norway rat droppings are larger, around ¾” with blunted ends. Other common signs are finding damaged items, gnaw marks, and nests, as well as greasy rub marks. You may also hear noises in the walls or the attic, and damaged electrical wiring.
To prevent roof rats from infesting your home, seal any cracks or holes larger than a nickel. This can be accomplished with silicone caulk. Likewise, assure that all the vents and windows are screened. Keep bushes trimmed back away from the buildings, and cut off any tree limbs that overhang the roof. Also, roof rats are attracted to any available food source, so pick up any fruit that has fallen from the trees. Keep garbage receptacles tightly closed, and store your pet's food, as well as other dry food, in sealed containers. Finally, eliminate any outdoor water source, such as birdbaths, your pet's water dish or even a leaky sprinkler head.
If you think you have a roof rat infestation, contact a licensed pest control professional for a thorough inspection. They can help you develop an effective roof rat prevention and treatment plan.
Roof rats are omnivorous and will eat practically anything. However, they especially like nuts, seeds, and fruits. They can also eat snails and slugs, as well as insects, including cockroaches. If the roof rats live near water, they will also eat fish and shellfish.
Roof rats typically come out to feed at dusk, and once again before dawn. However, they can forage for food at any time of the night or day. They prefer to take their food and eat in a hidden area. Roof rats are food hoarders and will stash a supply of food.
Roof rats are mostly nocturnal and prefer cool weather. They will forage for food in groups, returning to the same food source, following the same path from their nests. While their climbing ability allows them to easily climb up to the attic and roof of your home, they can adapt to living in nearly any environment.
Roof rats typically live in colonies and like to nest in attics and rafters. However, they can also nest under and around buildings, and in wood piles and leaf debris. They like sheltered habitats and are attracted to dense vegetation as well as fruit trees. This means a property with lush landscaping, fruit trees, woodpiles and storage sheds are more likely to have a roof rat infestation.
When roof rats seek indoor shelter, they will enter a building through any access point larger than a nickel. They often enter by following pipes. They can also gnaw through drywall, wood, or even aluminum siding.
Roof rats have a short life span, only living for around a year. However, a female can have up to 40 offspring during her lifetime.
Roof rats were responsible for spreading bubonic plague during the Dark Ages in Europe. While bubonic plague is rare today, there are a few cases in the U.S. every year. Roof rats have fleas and can spread diseases like as typhus, and their urine can spread infectious jaundice. Rat droppings can spread trichinosis. Finally, these rats can contaminate food and food preparation areas, spreading food poisoning.
Roof rats can get aggressive if threatened, and in self-defense, may try to chase you away, or even bite. If you are bitten or scratched by a rat, you could contract rat-bite fever. Rat-bite fever symptoms include a headache, vomiting, as well as muscle and joint pain.