Roof Rat

Roof Rat Scientific Name: Rattus rattus

Roof Rat Facts

The roof rat, also known as the ‘black rat’ has quite the history, especially for being a rodent. Blamed for spreading the Black Death plague around Europe, the roof rat eventually made its way to North America—presumably on cargo ships—in the mid-17th century. Notorious for spreading disease to humans and livestock, the roof rat is an agile creature that will plague vegetation and attics. To the untrained eye, the roof rat can look similar to other rats native to North America and the non-native Norway rat; however, the roof rats are very distinguishable not only by their appearance, but by their abilities. Here are some of the Roof rat’s notable characteristics:

  • Although nicknamed the ‘black rat,’ this species is generally dark brown in color.
  • Remember one word: tail. While other rats in the United States. have shorter, hairy tails, the roof rat has a completely hairless tail that is longer than its entire body.
  • If there is one way to distinguish the roof rat’s ability from other species, it is their aptitude for climbing. Racing up walls, trees, and electrical wires, these rates are at home above the ground.
  • Very long and actually quite slender, these rats will range between 14 inches and 19 inches long. Other rats are generally shorter and broader.
  • Like other rats, this one is nocturnal and you will only see evidence of it during the day via droppings and partially eaten food.

Roof Rat Habitat

Scientists have concluded that roof rats prefer warmer, more humid climates, and have therefore stayed close to the Gulf of Mexico and Southern Atlantic and Pacific coastlines. However, in the past ten years, experts have seen rats spreading more inland in Texas and Arizona (most likely due to cargo trucks.) Although further from the ocean, the rats have acclimated well and pose a new problem to homeowners in these areas.

As previously mentioned, the roof rat is adept at climbing and will use this skill to get into attics and upper stories of office buildings and homes. The insulation in these buildings is often destroyed as the rats tear at it for nesting material. Unlike other rats, the roof rat species does not enjoy burrowing and will climb trees, garages, house plants woodpiles, garbage cans, etc. in order to find a nesting area off the ground. In order to gain access to buildings, a roof rat only needs a bottle-cap size hole to squeeze through. Once a roof rat establishes a nest they will return there during the day, but will most likely travel several miles at night to find fruit and vegetables to eat and store. For more information on the diet of rats visits What do rats eat?

Roof Rat Reproduction

Like other rodents, the roof rat can have up to five litters each year consisting of five to seven babies each. With this timeline, it is easy to imagine how the roof rat and others grow so fast in population and become difficult to eradicate. Once a baby is born it is dependent on its mother for three weeks before it can start to hunt for food completely on its own. Surprisingly, the roof rat only has to reach three months to grow into full sexual maturity and start reproducing.

Roof Rat Indications and Damages

The last thing one wants on their hands is an infestation of roof rats; they can do serious damage, not to mention they have the ability to spread diseases. Some things to look for if one suspects roof rats are:

  • Rat Droppings: These will generally only occur in high places (attics), so they may be less noticeable. Roof rat droppings will be dark in color and oval shaped.
  • Rat Holes: If there are holes in screen doors or the roof, this may be an indication that a roof rat has gained access. No matter how small the hole may seem, it is important that it be fixed immediately.
  • Food: The roof rat is extremely fond of fruit, particularly citrus fruit, and will generally leave the rinds or hollowed-out layers lying on the ground. Although this does not mean that they have already made a rat nest inside a house, it does mean that they procure food there and are more likely to climb into the house eventually.
  • Wiring: Since roof rats are prone to climbing up electrical wiring, they are also prone to gnaw at it and cause serious financial damage and make a house susceptible to fires.
  • Insulation: A favorite for nest building, the roof rat can tear out insulation and use it for its young. Again, this will generally take place in the attic and will be less noticeable at first.

Roof Rat Control

Although there are no completely foolproof methods to prevent roof rats coming into your home, there are a few ways to make your dwelling an undesirable place. Here are some tips:

  • Trees: Dissuade the roof rats from climbing onto your home by keeping your trees and plants well groomed and a good five feet away from the house. This is especially true with fruit or vegetable plants; keep a good distance between them and your dwelling – you may even consider setting traps around the trees.
  • Food: If you own pets or livestock, make sure that the food is securely inside for the night.
  • Cleanliness: In general you will need to upkeep your house and yard by not keeping piles of garbage, wood, soil, etc., close to the house. This also includes building maintenance; fix leaks, holes, and tears immediately to prevent them from getting bigger and being an attraction to the rats.
  • Traps: Preferable to poison, there are bait and snap traps that can help eliminate the number of roof rats you have. The traps should mirror the rats’ climbing ability by placing them vertical, near electrical wires, on roof beams, or in attics. Poisons should be a last resort as you don’t want the roof rat to wander and die in the attic or walls of your house.